Biology Final
Can a population exceed "K"?
"K" is only a mathematical concept so we can model populations with some predictability, and is something we'll never truly know. We can only estimate it from empirical observations, and then use those observations to predict K in other populations.
International cooperation and multiple strategies needed to address deforestation
(1) identifying and protecting the most diverse areas. (2) addressing the poverty that drives the need to destroy rain forests for human activities. -addressing Western consumption that drives the extraction of these resources (3) developing alternative sources of food and income. (4) reducing population growth. (5) making education about the value of biodiversity a central part of these solutions. -long term over short term gains
acid rain
In North America, precipitation has an average pH as low as 4.3 in some parts of the Northeast, nearly 1000 times more acidic than pure water, which has a pH of 7.0. High concentrations of sulfuric and nitric acids are to blame, and several factors play a role. The Northeast has more people per square mile than does the rest of the United States, and that means there are more houses, factories, and automobiles to burn the oil, coal, and gasoline that create acid precipitation. But not all of the pollution that causes acid precipitation is local. In the United States, the Midwest and Southeast have a large number of electric power plants that burn coal, and wind currents carry the sulfur dioxide and nitrogen dioxide from these power plants across the Northeast. Precipitation in the western states is nearly 100 times more acidic than pure water because sulfur dioxide and nitrogen dioxide from Asia are converted to acids as they blow eastward across the Pacific Ocean. Precipitation in Europe and Asia is also acidified by local and distant sources of pollution.
Colonization events.
In a rare event, one or a few birds or small insects will fly off from a mainland and end up on a distant island group, such as Hawaii or the Galápagos Islands. Once there, they tend to find a large number of opportunities for adaptation and diversification. In the Galápagos, as we learned in Section 10-7, 14 finch species evolved from a single species found on the nearest mainland, 600 miles away. In Hawaii, there are several hundred species of fruit flies, all believed to have evolved from one species that colonized the islands—perhaps blown there by a storm, or carried there stuck in the feathers of a bird—and experienced an adaptive radiation.
biodiversity extrinsic value
In describing the extrinsic or utilitarian value of biodiversity, scientists and economists use the concept of ecosystem services to highlight the benefits to humans that come from biodiversity and natural ecosystems. In a 2005 United Nations study that involved more than 1,300 scientists, the researchers identified four distinct categories of ecosystem services.
earth recyclers
In every ecosystem, as energy is transformed through the steps of a food chain, organic material accumulates in the form of animal waste and dead plant and animal matter. Decomposers, usually bacteria or fungi, and detritivores, including scavengers such as vultures, worms, and a variety of arthropods, break down the organic material, harvesting energy still stored in the chemical bonds (Figure 15-13). Because the decomposers are able to break down a much larger range of organic molecules, they are distinguished from the detritivores. Both groups, nonetheless, release many important chemical components from the organic material than can eventually be recycled and utilized by plants and other primary producers.
Antarctic Ozone Depletion detailed
In the 1970s, scientists noted that the amount of ozone in the stratosphere was decreasing by about 4% per decade. The cold temperatures and circular flows of air that develop over the Poles during the winter concentrate CFCs, forming ozone holes in those locations. The Antarctic ozone hole, which lasts for several months, covers the entire continent of Antarctica and extends northward to include the southern tips of South America and Australia (Figure 16-31). The Arctic ozone hole is smaller than the Antarctic hole and does not last as long, but it is large enough to extend southward into northern Europe, Asia, and North America.
Evolutionary innovations.
In the world of computers, software developers are always looking for the "killer app"—the new application so useful that it immediately leads to huge success, opening up a large new niche in the software market or greatly expanding an already-existing niche. The first spreadsheet, email program, and web browser were all killer apps. In nature, evolution sometimes produces killer apps, too. These are innovations such as the wings and rigid outer skeleton that appeared in insects and helped them diversify into the most successful group of animals, with more than 800,000 species today (more than a hundred times the number of mammalian species). The flower is another innovation that propelled an explosion of diversity and ensured the evolutionary success of flowering plants relative to the non-flowering plants, such as ferns and pine trees. Today, about 9 out of 10 plant species are flowering plants.
greenhouse cycle
Increasing Temp --> Melting of permafrost --> Release of CO2 cycle
what is a niche influenced by?
Influenced by the abiotic environment -Moisture, light, temperature, pH, salinity, pressure, etc. Influenced by the biotic environment -Interactions with other organisms
eutrophication detailed
Like nitrogen, phosphorus is often a limiting resource in soils, constraining plant growth. Consequently, fertilizers usually contain large amounts of phosphorus. This is beneficial in the short run, but it can have some disastrous unintended consequences. As more and more phosphorus (and nitrogen) is added to soil, some of it runs off with water and ends up in lakes, ponds, and rivers. In these habitats, also, it acts as a fertilizer, making spectacular growth possible for algae. But eventually, the algae die and sink, creating a huge source of food for bacteria. The bacteria population increases and can use up too much of the dissolved oxygen, causing fish, insects, and many other organisms to suffocate and die. This process of excess nutrients leading to rapid growth of algae and bacteria, followed by large-scale die-offs, is called eutrophication. It is increasingly a problem in both small and large bodies of water, affecting more than half of the lakes in Asia, Europe, and North America. Lake Erie, on the U.S.-Canadian border, for example, has experienced eutrophication as a result of all the phosphorus- and nitrogen-containing waste water that drains into it from the extensive surrounding farmlands. Given the lower use of fertilizers in South America and Africa, eutrophication is less common there.
Microbes Can
Live Almost Anywhere and Eat Almost Anything
The use of antibiotics in agriculture is another reason for the spread of antibiotic resistance.
Low concentrations of antibiotics are routinely added to the feed for cattle, hogs, chickens, and turkeys. This can be beneficial in the short term, promoting growth and minimizing disease in the crowded conditions of commercial meat and milk production. But in the long run it can have disastrous consequences, as the practice can lead to selection for bacteria resistant to the antibiotics. The antibiotics can also pass through the food chain to humans. Data gathered by the Union of Concerned Scientists indicate that agriculture in the United States uses about 25 million pounds of antibiotics each year—about eight times more than is used for all human medicine!
The dose is the poison...but the solution is not dilution
Low/balanced concentrations -Non-toxic -Beneficial/required High concentrations -Can be toxic -Creates unbalanced ecosystems -Some pollutants can bioaccumulate in the ecosystem, though found in the environment at low concentrations eventually accumulates in organisms (DDT, mercury, Al, other heavy metals, etc.) Everything in a large enough concentration can be harmful, balance is the key. In some cases even small amounts of some substances can accumulate eventually creating highly dangerous concentrations.
Plants and animals aren't the only species with great value to humans.
Microbes, too, have great utility. In the next section, for example, we see that hydrocarbon-consuming bacteria can play a significant role in cleaning up oil spills (Figure 16-2). Sure enough, as the researchers sampled the water and evaluated oxygen concentrations, they noted an unprecedented, significant drop in oxygen saturation—down from 67% to 59%. This suggested that bacterial populations were proliferating rapidly and "mopping up" the oil. Making some calculations, the researchers found that the amount of missing oxygen was almost exactly equal to the amount required by bacteria to consume the amount of methane that had leaked from the well. "The math worked out scary good," is how one researcher put it.
Overview of plants
Mosses (Bryophytes) -No vascular system or true roots, very short, reproduces via spores Ferns -Can grow to the size of trees, vascular system, reproduces via spores Gymnosperms -Can grow the size of trees, vascular system, no flowers but produces by seeds Angiosperms -Can grow the size of trees, vascular, produces flowers and produces seeds covered by fruity flesh
As industrialization continues, further changes occur.
Most importantly, a higher standard of living is attained. This results from higher levels of education and employment and, in conjunction with the improved health care, finally causes a reduction in the birth rate. The new, lower birth rate then slows the population's growth. The progression from: 1) high birth rates and high death rates to (slow population growth) 2) high birth rates and low death rates to (fast population growth) 3) low birth rates and low death rates (slow population growth) is called the demographic transition.
Colorado River supplies much of the west with water
Most of the river's water comes from melting snow pack which has been declining for decades The river no longer makes it to the ocean under normal conditions, though Mexico and the USA have been working to rehabilitate the ecosystem with planned dam releases to restore the coastal ecosystems
That is the situation that the first modern Homo sapiens encountered when they left Africa.
Neandertals (Homo neanderthalensis) had spread across Europe and the Middle East. Neandertals were about the same size as modern humans but they were more robust and muscular. Fossils of Neandertals often include bones that had been broken and healed. These injuries provide two types of information about Neandertals: Neandertals must have lived in organized groups that included a social support system, because these were serious injuries. The victims would have been incapacitated for days or even weeks until they healed, and family or clan members must have cared for them during this period. Ritual burials of Neandertals have also been found, and these provide additional support for the hypothesis that they lived in organized social groups. The pattern of injuries found in Neandertal skeletons is distinctive—the only modern counterpart is found in professional rodeo bull and bronco riders, people who come in very close contact with large, angry animals. Neandertals probably hunted large mammals (bison, mammoths, wooly rhinoceroses) with short spears that were used for close-up jabbing instead of being thrown from a safe distance.
After modern H. sapiens groups spread into the areas occupied by the three other human species, these three other species disappeared.
Neandertals became extinct about 30,000 years ago, H. erectus about 27,000 years ago, and H. floresiensis about 12,000 years ago.
What happened to the 3 other human species?
Neandertals became extinct ~30,000 years ago. -H. sapiens share between 1-4% DNA H. erectus: extinct ~27,000 years ago. H. floresiensis : extinct ~12,000 years ago. -H. sapiens already domesticating figs around this time.
The nitrogen cycle detailed
Nitrogen is necessary to build all amino acids, the components of every protein molecule, as well as the precursors of other nitrogen-containing molecules—all critical to life. Like carbon, the chief reservoir of nitrogen is the atmosphere. But even though more than 78% of the atmosphere is nitrogen gas (N2), for most organisms, this nitrogen is completely unusable. The problem is that atmospheric nitrogen consists of two nitrogen atoms bonded tightly together, and these bonds need to be broken to make the nitrogen usable for living organisms. Only through the metabolic magic (chemistry, actually) of some soil-dwelling bacteria, the nitrogen-fixers, can most nitrogen enter the food chain. These bacteria chemically convert or "fix" nitrogen by attaching it to other atoms, including hydrogen, producing ammonia and related compounds. These compounds are then further modified by other bacteria into a form that can be taken up by plants and used to build proteins. And once nitrogen is in plant tissues, animals acquire it in the same way they acquire carbon: by eating the plants. Nitrogen returns to the atmosphere when animal wastes and dead animals are broken down by soil bacteria that convert the nitrogen compounds in tissue back to nitrogen gas.
ohio temp trends
Not every area in Ohio has warmed over 115 yrs, also in the past 20 yrs over all it has cooled. Unfortunately for the U.S. and the world as a whole it has warmed. Be wary of claims based on short term data or local areas
How effective are they at absorbing nutrients and growing? Here's a question: What is the largest living organism in the world?
Not surprisingly (considering where we are asking this question), it is a fungus—specifically a yellow honey mushroom fungus that covers an area of nearly 10 square kilometers (about four square miles) in eastern Oregon. This fungus is estimated to be at least 2400 years old and it may be more than 8000 years old, which would place it in the category of the oldest living organisms. Moreover, by area, it is the largest.
Baby boomers and retirement
Notice the "bulge" in the U.S. age pyramid. The shape of the age pyramid in the United States has economists worried that the social security system (including Social Security and Medicare) will not be able to offer older citizens sufficient benefits in the next 10-30 years. Because of the unusually large number of babies born about 50-65 years ago, an unusually large number of people are now reaching retirement age. Since the baby boomers were born, there haven't been any years with such a large cohort. This means that the current numbers of working individuals who contribute to the social security system are not sufficient to cover the payouts promised to the large number of retirees, and the baby boomers will be expensive to support as they reach retirement.
What We Often Do Not Know...
Number of individuals alive Population carrying capacity Stability of carrying capacity from year to year -"K" changes Which individuals to harvest
1) Solar energy available.
Perhaps the simplest predictor of species diversity is climatic favorability, the amount of solar energy available in an area. In a variety of species of plants and animals, researchers have documented strong relationships between energy availability and species richness.
2) Increasing greenhouse gases.
Photosynthesis in tropical rain forests removes an estimated 610 billion tons (550 trillion kilograms) of carbon dioxide from the atmosphere each year. Accumulation of carbon dioxide is the major cause of global warming, and the photosynthetic activity of tropical rain forests is slowing the rate of warming. The huge quantity of carbon stored in rain forests has a downside, however, because that carbon is released into the atmosphere when forests are cleared and burned. And tropical forests are being cleared at a frightening rate—nearly 12 square miles (30 square kilometers) per day, which means a total of 200,000 square miles (more than 500,000 square kilometers) just from 2000 to 2005!
Aral Sea (was 4th largest lake)
Poor crop (cotton) choice and irrigation techniques. Barely any regulation of water use to farmers weren't paying or conserving water. Increasing temperatures exasperated problem.
Take-home message 14.3 population growth
Populations tend to grow exponentially if "r" remains fairly constant, but this growth is eventually limited.
2) All animals with defined tissues develop in a shape that has some sort of symmetry: radial or bilateral.
Radial symmetry describes animals with a body structured like a pie, such as jellyfishes, corals, and sea anemones. Slow-moving or free-floating, radially symmetrical animals have no front or back ends, and it is possible to make multiple slices, all going through the center, that divide the organism into identical pieces. In contrast, organisms with bilateral symmetry (such as humans, cows, and scorpions) have left and right sides that are mirror images. These animals can move adeptly, searching for food and avoiding predators.
Many of the most biological diverse areas of the planet are under intense deforestation pressure
Reduces biodiversity Increases greenhouse gases
1) Flagship species.
Some species, because they are particularly charismatic, distinctive, vulnerable, or otherwise appealing, can engender significant public support. Examples include the giant panda of China, the golden lion tamarin of Brazil's coastal forest, the mountain gorilla of Central Africa, the orangutan of Southeast Asia, the leatherback sea turtle, the Indian tiger, and the African elephant. Preservation of these species, given their habitat needs, can serve to preserve many other species as well.
Warning Coloration
Species protected from predation by toxic chemicals frequently have evolved bright color patterns to warn potential predators. They are essentially carrying a sign that says: "Warning, I'm poisonous, so keep away." To make it as easy as possible for predators to learn, different poisonous species often have the same color patterns. In a clever twist on this, some species that are perfectly edible to their predators also have evolved the same bright colors, in a phenomenon known as mimicry. Their coloration mimics the same warning sign but without the toxins. As long as they are relatively rare compared with the toxic individuals they mimic—reducing the chance that predators might catch on to their trickery—the evolutionary ruse is quite successful. Monarchs eat toxic milkweed to build the chemical defense, they don't produce it Animals learn that the pattern is associated with food that tastes bad or makes them sick
Microbes are abundant!
Surface sea water contains more than 100,000 bacterial cells per milliliter, and diatoms (a protist in the eukarya domain) are as abundant as bacteria. Those densities translate to about 8000 million billion trillion (8 x 1030) individuals of just these two kinds of microbes in the world's oceans. Your own body is a testament to the abundance of microbes: it contains about 100 trillion cells, but only one-tenth of those cells are actually human cells—the remaining 90 trillion cells are the microbes that live in and on you. You're a minority in your own body.
There's more to a tree than its trunk, however, and trunks can be replaced.
That is what a Norway spruce in Sweden has been doing—the current trunk is about 600 years old, but the roots are 9550 years old. This tree has persisted by sending up a new trunk each time the old one dies. But conifers aren't all big; there also are miniature species of conifers like the shore pine, which can be only 20 centimeters tall.
10% rule
The 10% rule: only about 10% of the biomass from each trophic level is converted into biomass in the next trophic level. The rest of the available energy is lost to the env, a consequence of several factors, including non-predatory deaths, incomplete digestion of pre/food, and respiration
preserving species vs preserving habitats
The ESA has had the effect of focusing most conservation efforts on the preservation of individual species (and populations), sometimes at the expense of other elements of biodiversity and sometimes at the expense of efforts to reduce the loss of ecologically important habitats (Figure 16-34). Other difficulties also are associated with the ESA. Consider the task of determining the critical population size below which a population is endangered—is it 500 individuals, 5,000, or 50,000? With its emphasis on preservation of single species, the ESA does not effectively address ecosystem decline, which is an equally urgent and serious problem.
Water is Life
The affect of a warming planet is also changing weather patterns and subsequently planetary water distribution Some areas will see increased rainfall while many others will see reduced rainfall Poor water management also exasperates water issues -Large populations living in water scarce areas -Growing crops not fit for the environment --Poor irrigation techniques
deforestation
The chief reason for the loss and impending loss of so many species is habitat loss and habitat degradation. Particularly harmful is habitat loss in earth's tropical rain forests, where biodiversity is greatest. In the past 25 years, half of the world's tropical rain forests have been destroyed, usually by burning to make way for agricultural use of the land or by logging. Urban development, too, is responsible for destruction of rain forests, as the growing human populations continue to expand. Intensive agriculture, livestock grazing, and the development of urban centers has led to the destruction and fragmentation of habitats worldwide.
Preserved Fern Forest, Eastern Illinois
The fossil fuels we use today, mainly coal, was able to form because the ability to breakdown cellulose had yet to evolve.
But the question remains: how high can the population go?
The most difficult problem in determining the earth's carrying capacity for humans may be assessing just how many resources each person needs. It is possible to estimate the ecological footprint of an individual or an entire country by evaluating how much land, food, water, and fuel, among other things, are used. This method reveals that although some countries (e.g., New Zealand, Canada, and Sweden) have more resources available than are required to support the needs of their population, resource use in the world as a whole is significantly greater than the resources available, implying that we are already at our planet's carrying capacity. The populations of many countries—including the United States, Japan, Germany, and England—currently consume an unsustainable level of resources.
greenhouse effect detailed
The term "greenhouse effect" describes the process by which energy from the sun warms the earth's atmosphere. The light we see lies in the visible portion of the light spectrum, and visible wavelengths of light pass easily through the atmosphere to warm the earth's surface. Some energy in the infrared part of the spectrum flows from earth back toward space, and several gases in the atmosphere absorb this energy, heating the air. These gases act like the glass panels that make up the roof of a greenhouse: they allow light energy to pass through, but they keep heat from escaping—hence the name "greenhouse gases." Carbon dioxide and methane are among the most important of the greenhouse gases.
toxic algae
The toxic algae was always there, but just in low numbers since it isn't very efficient at utilizing nutrients. By having an excess of nutrients the toxic algae is now able to grow almost as well as the other algae, but since it has the toxin the advantage goes to it.
Interacting species evolve together.
There is a moth in Madagascar with a tongue that is 11 inches long! This might seem absurd—until the moth approaches a similarly odd-looking orchid. The orchid's flower has a very long tube, also about 11 inches long, that has a bit of nectar at the very bottom. The moth's tongue, although usually rolled up, straightens out as fluid is pumped into it and can be inserted into the long nectar tube. As its tongue reaches the bottom, the moth slurps up the nectar, gaining nourishment and energy. The moth also gets a bit of pollen stuck to it in the process, pollen that gets brushed onto the reproductive parts of the next orchid flower it visits. But how did such a system ever originate? Which came first, the long-tongued moths or the long-tubed flowers? Each trait only seems to make sense in a world in which the other already exists. The answer is that neither came first. They both evolved—coevolved—together.
3) Indicator species.
These are species whose presence within an ecosystem indicates the presence of a large range of other species. For example, the presence or absence of lichens is an indicator of air quality because they are sensitive to sulfur dioxide, a component of industrial fumes. When lichens disappear from trees, it is usually an indicator of increased pollution, which endangers the entire ecosystem. Conversely, when the lichens are present and healthy, they indicate that the ecosystem is healthy.
4) Umbrella species.
These include wide-ranging species with such large needs for habitat and other resources that their preservation ends up protecting the numerous other species within that same habitat, without having to identify these other species as conservation targets. Umbrella species tend to be large, wide-ranging vertebrates.
disruptive impacts: deforestation detailed
Towering trees, colorful birds and butterflies, maybe a glimpse of Tarzan swinging past on a hanging vine—that is the popular image of a tropical rain forest. And it is a reasonably accurate picture (minus the Tarzan part). But it is also a picture that is rapidly fading, as agriculture, logging, gold mines, and oil wells destroy tropical forests.
Biological systems are also showing the effects of climate change.
Trees and flowers: bloom earlier Migratory birds: travel earlier Birds and butterflies: moving their range northward
1) Reducing biodiversity. 2) Increasing greenhouse gases.
Tropical rain forests grow in a region extending just a bit north and south of the equator, in South America, Africa, Asia, and Australia. As recently as a few centuries ago, that belt of rain forest covered about 6 million square miles (15.5 million square kilometers). More than half of that forest already has been destroyed, most of it in just the past 200 years. Destruction of tropical rain forests has two serious environmental impacts: reducing the earth's biodiversity and increasing the concentration of greenhouse gases in the atmosphere.
What do ecologists do?
Try to determine populations -usually estimates, spatially and temporally dependent How one population interacts with another -Same or different species Predict patterns of population growth Examine interactions between organisms and the environment Help manage natural resources -Extraction and preservation
Figuring Out How a Population Grows (or Shrinks)
Two pieces of information are needed: Growth rate, abbreviated as "r" Is the culmination of the births and deaths Number of individuals in the population (N) r x N
Producers:
Uses an energy source to create chemical energy (most cases it is light used to make glucose)
Natural selection in nature
Variation for a trait: running speed in rabbits can vary from one individual to the next Heritability: the trait of running speed is passed on from parents to their offpsring Differential reproductive success: in a population, rabbits with slower running speeds are eaten by the fox, and their traits are not passed on to the next generation
How high can it go?!
Very difficult to assess just how many resources each person needs. Ecological footprints -Evaluating how much land, how much food and water, and how much fuel, among other things, are necessary. -Essentially how much of Earth's resources do you consume
energy pyramids
We can illustrate the path of energy through the organisms of an ecosystem with an energy pyramid in which each layer of the pyramid represents the biomass of a trophic level. In Figure 15-14 (Inefficiencies in the transfer of biomass), we can see that, for terrestrial ecosystems, the biomass (in kilograms per square meter) found in the photosynthetic organisms, at the base of the pyramid, is reduced significantly at each step, given the incomplete utilization by organisms higher up the food chain.
More than just a place for living, a niche is a complete way of living.
We can think of an organism's niche as its place in the community. More than just a place for living, however, a niche is a complete way of living. In other words, an organism's niche encompasses 1) the space it requires, 2) the type and amount of food it consumes, 3) the timing of its reproduction (its life history), 4) its temperature and moisture requirements, and virtually every other aspect that describes the way the organism uses its environment . Although a niche describes the role a species can play within a community, the species doesn't always get to have that exact role. Consider the rats of Boston. Until the 1990s, they lived in relative peace in the sewers beneath the city's streets. But when the city embarked on the largest underground highway construction project in U.S. history, engineers displaced and forcibly drove out thousands of rats from much of their habitat. In essence, there was suddenly an overlap between the rat niche and the human niche, and the rats were now restricted to just some portions of the sewer. As a result, the rats' realized niche, where and how they are actually living, is now just a subset of their fundamental niche, the full range of environmental conditions under which they can live.
Figuring Out How a Population Grows (or Shrinks) detailed
We start by figuring out how a population grows if each individual does more than just "replace" itself. Two pieces of information will tell us how much a population is growing (or shrinking). The first is the growth rate, abbreviated as "r." This is simply the rate of births minus the rate of deaths. If the rate of births is greater than the rate of deaths, the population gets bigger. If the death rate is bigger, "r" becomes a negative number and the population gets smaller. For example, if there are 500 individuals in a population and over the course of the year 125 offspring are born, the birth rate is 125/500 or .25 births per person. And if 25 out of the 500 individuals die during the course of the same year, the death rate is 25/500 or .05 deaths per person. In this population, then, the growth rate is .25 .05 or .20 individuals per person. But how many individuals is that?
Why did these three species vanish?
We're not sure. Previously, researchers thought that modern H. sapiens must have exterminated the other species, either by monopolizing access to food and living space or by killing them in battles for food and space. But recent results from DNA sequencing suggest that H. sapiens actually encountered and interbred with Neandertals, just as they emerged from Africa. This conclusion is based on the finding that at least 1% to 4% of the genetic makeup of most modern humans includes Neandertal DNA.
Factors that strike populations without regard for the size of the population
Weather-based Natural disasters
Population Ecology
What is a life history? Introduce survivorship curves. -How life history affects survivorship and vice versa Human populations -Age pyramids -Demographic transitions
ecosystems detailed
What is important is that the two essential elements of an ecosystem are present: the biotic environment and the physical (abiotic) environment. Biologists view communities of organisms and their habitats as "systems" in much the same way that engineers might, hence the term ecosystem. Biologists monitor the inputs and outputs of the system, tracing the flow of energy and various molecules as they are captured, transformed, and utilized by organisms and later exit the system or are recycled. They also study how the activities of one species affect the other species in the community—whether the species have a conflicting relationship, such as predator and prey, or a complementary relationship, such as flowering plants and their pollinators. Regardless of size, the same principles of ecosystem study apply: observe and analyze organisms and their environments, while monitoring everything that goes into and comes out of the system: salinity (salt level), moisture, humidity, and energy sources.
Biomes: large ecosystems that occur around the world
What is the average temperature? -As well as is it constant or does it vary seasonally? What is the average precipitation? -As well as is it constant or does it vary seasonally?
Specifically, when defining terrestrial biomes, we ask four questions about the weather:
What is the average temperature? What is the average rainfall (or other precipitation)? Is the temperature relatively constant, or does it vary seasonally? Is the rainfall relatively constant, or does it vary seasonally? These abiotic factors greatly influence the biology that is present in those areas.
Natural Resource Management
What to do when organisms with great value appear to be threatened by the predatory behavior of another species? Not all plants have ant defenders so creating a defense for susceptible plants is a strategy. -Such as a barrier to large herbivores
Adaptive radiations are times of extreme diversification of species.
When a small number of species diversifies into a much larger number of species In a brief period of time, a small number of species diversified into a much larger number of species, able to live in a wide diversity of habitats. Called an adaptive radiation, such a large and rapid diversification has occurred many times throughout history.
Why is it essential to take every dose of an antibiotic prescribed by a doctor?
When an antibiotic is taken as prescribed—that is, at the times specified on the label and until all the pills have been consumed—the population of target bacteria is greatly reduced. All of the bacteria that remain are resistant to the antibiotic, but there are not very many of them. The growth of these resistant bacteria will be held in check by competition with other types of bacteria. If you stop taking the antibiotics before you have finished all of the prescription, however, there are many bacterial cells still alive, and these include the ones that were most resistant to the antibiotic. These resistant cells will be the founders of the new population of bacteria in your body, so the next time you take that drug it will be ineffective. Even worse, taking antibiotics when they are not needed—to treat a viral infection, for example—selects for resistant bacteria without providing any benefit because antibiotics have no effect on viruses.
1. Reduced predation → reduced investment in defense against predators.
When protected from elephants and giraffes, the acacias somehow detected the reduced herbivory and reduced their investment in supporting the symbiotic ants: they decreased by one-third the number of nectar-producing sites, and they produced fewer swollen thorns in which the ants could live.
2. Reduced support of ants → reduced defense behavior by ants.
When the nectar reward dwindled, the ants played a lesser role in plant defense: there was a 30% reduction in the number of ants remaining on the plants, and among the remaining ants, 50% fewer individuals responded to disturbances of the plant—and those that did were significantly less aggressive in their response.
3. Reduced number of ants → opportunity for competitors to get in.
When the number of mutualistic ants dwindled, this created an opportunity for competing (non-mutualistic) species of ants to take up residence in the acacias. The proportion of trees occupied by these competing, non-mutualistic ants doubled.
Mass extinction events.
With the near-total disappearance of the dinosaurs, a world of "opportunities" opened up for the mammals. Where previously the dinosaurs had prevented mammals from utilizing resources, mammals suddenly had few competitors. Not surprisingly, the number of mammalian species increased from perhaps just a few hundred to more than 4,000 species in about 130 genera. This happened over about 10 million years, barely the blink of an eye by geological standards. Following other large-scale extinctions, numerous other groups that suddenly lost most of their competitors experienced similar adaptive radiations.
Keystone Species
Within a community, the presence of some species, called keystone species, greatly influences which other species are present and which are not. That is, if a keystone species is removed, the species mix in the community changes dramatically. The removal of other species, conversely, causes relatively little change. Bison are a keystone species. Sea stars, too, are a keystone species. Keystone species make it possible to get more "bang for your buck" when your aim is to conserve biodiversity. Consequently, identifying keystone species is an important part of conservation biology. Some other keystone species include dam-building beavers, elephants of the African savanna, and lichens in the desert.
what are the closest living relatives of humans?
Within the apes, genetic and anatomical characteristics show that chimpanzees are the closest living relatives of humans. Human and chimpanzee genes are very similar—their base sequences differ by about 1%, and one-third of human and chimpanzee genes are identical.
The habitat conservation approach is not new. The very first attempts at conservation were the creation of
Yellowstone Park in 1872 and Yosemite in 1890, both large-scale efforts geared not simply toward the preservation of one or a few species but rather at preserving wilderness. In the time since then, significant efforts have been made to establish national parks, wilderness areas, and recreation areas.
Population Growth Rate Calculation 500 individuals in a population. One year 125 offspring are born. Birth rate is 125/500 or 0.25 births per person. One year 500 individuals the death rate is 50/500 or 0.10 deaths per person. The growth rate is 0.25 0.10 or 0.15 individuals per person. (r = 0.15)
You can also think of it as 125 born minus the 50 that die so; 125 - 50 = 75 born. That's 75 born per 500 individuals which is ; 75/500 = 0.15.
Chitin:
a carbohydrate polymer that is very tough, and is found in the exoskeletons of bugs
Plants and mycorrhizal fungi have
a close and mutually beneficial association
More than just a place for living, a niche is
a complete way of living.
The Endangered Species Act
a law that defines endangered species as those in danger of extinction throughout all or a significant portion of their range. -Only addresses species, not ecosystems
Biodiversity:
a measure of the community diversity, amount and ratio of different species, in a given area. It is a general measurement of ecosystem health.
About every 50 years
a new variety of influenza causes a pandemic. The 20th century has seen three major influenza pandemics, and all of them originated in the same peculiar way. In each of these pandemics, a bird virus gained the ability to infect human cells by passing through pigs, and then spread rapidly through the human population of the world. The most famous of these pandemics occurred in 19181919. The influenza pandemic of 19181919 killed millions). It was called the Spanish Influenza because it appears to have entered Europe through Spain, but it originated in Asia. The Asian flu and Hong Kong flu pandemics also originated in Asia, as have smaller viral outbreaks, such as Korean flu (1947), swine fever (1976), and the SARS virus (20022003), which did not become pandemics.
These difficult questions are all part of ecology,
a sub-discipline of biology defined as the study of the interactions between organisms and their environments. But don't be fooled by the simple definition. Ecology encompasses a very large range of interactions and units of observation and is studied at different levels. These include: Individuals: How do individual organisms respond biochemically, physiologically, and behaviorally to their environment? Populations: How do groups of interbreeding individuals change over time in terms of their growth rates, distributions, and genetic makeup? Communities: How do the populations of different species within a locale interact with each other? Ecosystems: At the highest level of organization within ecology, how do the living and non-living elements interact in a particular area, such as a forest, desert, or wetland?
Most viruses have
a very small amount of genetic material (7.8 x 10-6 of a percent compare to plants and animals) (*my calculation using these numbers*)
The appearance of flowering plants (angiosperms)
about 135 million years ago set the stage for the botanical world we know today, with flowering trees, flowering bushes, and all the grasses and herbaceous (non-woody) plants we see around us.
human migration out of africa
about 60,000 years ago, a small group of modern humans left africa and they ultimately spread across the earth. mitochondrial DNA shows that this migration followed 3 major pathways
Microbes are
abundant.
Mass extinction events. Colonization events. Evolutionary innovations. All result in
access to plentiful new resources.
Heterotroph: Autotroph:
acquires food makes food
problem: desiccation
adaptation: plants developed an outer waxy layer called a cuticle that covers their entire surface
problem: gravity
adaptation: the earliest plants grew very close to the ground, as mosses do today, in order to resist the pull of gravity
As countries industrialize there is
also a baby boom
big bang reproduction
antechinus reaches sexual maturity in one year mates intensively over 3 week period males die shortly after mating period females usually die after weaning their first litter
Humans are part of the
anthropoid lineage of primates, which includes the New World and Old World monkeys (both of which have tails) and the apes (which lack tails). Among the apes, gibbons and orangutans live in pairs or alone, while gorillas and chimpanzees live in social groups that consist of one or more adult males and several females, the ancestral social structure for human societies.
Fossil fuels
are created when large numbers of organisms die and are buried in sediment lacking oxygen. In the absence of oxygen, at high pressures, and after very long periods of time, the organic remains are ultimately transformed into coal, oil, and natural gas. Trapped underground or in rock, these sources of carbon played little role in the global carbon cycle until humans in industrialized countries began using fossil fuels to power various technologies. Burning coal, oil, and natural gas releases large amounts of carbon dioxide, thus increasing the average CO2 concentration in the atmosphere—the current level of CO2 in the atmosphere is the highest it has been in almost half a million years. This has potentially disastrous implications, as we will see in Chapter 16.
Taxonomic families
are large groups of similar organisms. This graph shows over time that the earth has had a steady rise of different species though there were some dips. Another thing that confounds our knowledge is as we try to search deeper in time it becomes harder and harder to find evidence of past organisms.
Some "mega-viruses" have been discovered that
are larger and have more genetic material than some bacteria
One important feature that makes bacterial diversity possible is that
bacteria can metabolize almost anything. Some of them can even use energy from light to make their own food. Microbiologists place bacteria into trophic (feeding) categories that reflect their metabolic specialization.
why aren't viruses considered living?
because they are dependent on their hosts' metabolic machinery for replication
Primary succession
begins after a disturbance leaves an area barren of soil and with no life
parasitism
benefit to one species while undesirable effect to the other. (predator/prey relationships)
The variety of flower structures is tremendous. They differ in shape, color, smell, time of day during which they are open, whether they produce nectar, and whether their pollen is edible. And just as the variety of flower types is wide, so too is the variety of pollinators great:
birds (mostly hummingbirds), bees, flies, beetles, butterflies, moths, and even some mammals (mostly bats).
3) Habitat tolerance:
broad versus narrow. "Habitat tolerance" describes the breadth of habitats in which a species can survive. Some plant species, for example, can tolerate large swings in water availability or soil pH or temperature. Others are limited to very narrow habitat ranges. The now-extinct passenger pigeons could only build nests in a specific type of forest and needed large numbers of individuals, breeding communally, in order to breed successfully. As forests were cut down and as the birds were hunted, the size of their flocks diminished. Their narrow habitat tolerance made them extremely vulnerable to extinction. In general, because species with narrow habitat tolerance cannot adapt in the face of habitat degradation and loss, they are at greater risk than species with broader habitat tolerance.
Unlikely as it seems, non-vascular plants
can grow in deserts, and mosses (along with lichens and cyanobacteria) are important components of the biological crust that holds desert soils in place. The crust cements the soil particles together and allows the soil to resist wind erosion, but it is extremely fragile and very slow to regenerate. When people or cattle walk over the crust, they break it into small pieces that cannot resist wind, and erosion can then strip a meter or more of soil in a few decades, leaving tree trunks supported in mid-air by their roots.
Primary succession
can take thousands or even tens of thousands of years, but it generally occurs in a consistent sequence. It always begins with a disturbance that leaves an area barren of soil and with no life. Frequently, the disturbance is catastrophic. The huge volcanic eruption on Krakatoa, Indonesia, in 1883, for example, completely destroyed several islands and wiped out all life and soil on others. Primary succession has also begun, in a less dramatic fashion, in regions where glaciers have retreated, such as Glacier Bay, Alaska. Although succession does not occur in a single, definitive order, several steps are relatively common.
metabolic diversity among bacteria
chemoorganotrophs (feed on organic molecules) chemolithotrophs (feed on inorganic molecules) photoautotrophs (use energy from sunlight to produce glucose via photosynthesis)
Age pyramids: developing countries
developing countries, like kenya, have age pyramids that appear triangular in shape, due to high birth rates and the high death rates in older indvs
While bacteria are responsible for many diseases (i.e., strep throat, cholera, syphilis, pneumonia, botulism, anthrax, leprosy, and tuberculosis),
disease-causing bacteria are only a small fraction of the domain, and bacteria seem to get less credit for their many positive effects on our lives. Consider that bacteria (E. coli) that live in your gut help your body digest the food you eat and, in the process, make certain vitamins your body needs. Other bacteria (actinomycetes) produce antibiotics such as streptomycin.
microbes in the tree of life
domain bacteria domain archaea domain eukarya
-Fungus release
enzymes to decompose biomass, so nutrients can be absorbed across a membrane, like an animal's digestive tract
Of the 1.5 million named species, the majority are
eukarya, with about half being insects. This is more a result of the interests and biases of biologists than a reflection of the relative numbers of actual species in the world.
punctured equilibrium
evolution by jerks: long periods of relatively little evolutionary change are punctured by bursts of rapid change
Interacting species
evolve together.
Because of this strong coevolution between the plant and animal species, we can now discern much about the pollinator of a particular species of plant simply by
examining the flowers. In most cases, you can determine with certainty the type of animal that will pollinate a flower just by examining its features.
1) Geographic range:
extensive versus restricted. Species restricted in their range—including those limited to small bodies of water and those confined to islands—are more vulnerable than those with extensive ranges. The Tasmanian devil is a marsupial carnivore about the size of a dog. Although these animals once thrived in Australia, they now are confined to the island of Tasmania, smaller than the state of Maine. Unable to expand their range, Tasmanian devils are more vulnerable to extinction than if their range was not limited.
Adaptive radiations are times of
extreme diversification of species.
13.5 Metabolic diversity among the bacteria is
extreme.
Bioengineers and biotechnologists believe that
extremophile archaea and bacteria that thrive at high temperatures and pressures and metabolize toxic substances have enormous potential for industries that carry out activities under such conditions. Recent experiments have demonstrated the ability of some archaea to efficiently degrade hydrocarbons, making it possible for them to be used in the removal of sludge that accumulates in oil refinery tanks and, potentially, in the cleanup of contaminated environments such as oil slicks. Naturally occurring archaea are helping to break down some of the more than 200 million gallons of oil released into the Gulf of Mexico following an oil rig explosion and subsequent massive leak in 2010. Other archaea show promise in clearing mineral deposits from pipes in the cooling systems of power plants.
The fact that a species exists means it can do the things all organisms must do:
find food escape predators reproduce
The evolutionary tree of plants shows these stages clearly:
first the development of vessels to conduct water from the soil through the plant, then seeds that provide nutrients to get new plants off to a good start (Gymnosperms), and finally flowers that allow plants to entice or trick insects and birds to spread the plants' male gametes (Angiosperms).
Providing a food source:
fleshy fruit is a form of bait that lures an animal to eat the seed and carry it far from the parent plant before eliminating it.
The vast majority of plants on earth are
flowering plants in the angiosperm group, and almost exclusively all our agricultural crops are angiosperms.
The eukarya domain consists of
four kingdoms. Plants, Animals, Fungi, and Protists
Fungi are decomposers of symbionts:
fungi acquire energy by breaking down the tissues of dead organisms or by absorbing nutrient from living organisms
Fungi are sessile:
fungi are anchored to the organix material on which they feed.
Fungi have cell walls made of chitin:
fungi have cell walls containing chitin, a chemical that is also important in producing the exoskeleton of insects.
conifers
have grown taller and reached older ages than any other plant
The demographic transition illustrates how
health, wealth, and education can lead to a reduction in the birth rate without direct government interventions.
-Fungus are________ they can/can't produce their own food
heterotrophs, they cannot produce their own food (decomposer)
type 3 survivorship curve
high mortality early in life, but those that survive the early years live long lives
type 1 survivorship curve
high survivorship until old age, then rapidly decreasing survivorship
fast intensive reproductive investment
house mouse reaches sexual maturity at one month produces litters of six to ten offspring every month
Biomes cover
huge geographic areas of land or water—the deserts that stretch almost all the way across the northern part of Africa, for example. Terrestrial (land) biomes are defined and usually described by the predominant types of plant life in the area. But looking at a map of the world's terrestrial biomes, it is clear that they are mostly determined by the weather.
All animals share a common ancestor, the ancestral protist, but these four key distinctions help us
identify and organize all of the approximately 36 phyla of living animals into monophyletic groups. Additional evolutionary transitions have occurred within the groups created by these four distinctions, allowing further categorization of animals into monophyletic groups.
mosses
important components of many soils. w/o them wind erosion can strip away unprotected soil, leaving tree trunks supported in mid-air by their roots.
for phosphorous, the most important reservoir is
in the soil
age pyramids: industrialized countries
industrialized countries, such as norway, have age pyramids that appear more rectangular in shape, due to low birth rates and the low death rates in older indvs
2) Resource partitioning
is an alternative outcome of niche overlap. Individual organisms and species can adapt to changing environmental conditions, and resource partitioning can result from an organism's behavioral change or a change in its structure. When this occurs, one or both species become restricted in some aspect of their niche, dividing the resource. In other experiments with Paramecium, for example, one of the two species was replaced with a different species. As in the initial experiment, either species thrived when grown alone. But when the two species were grown together in the same test tube, they ended up dividing the test tube "habitat." One species fed exclusively at the bottom of the test tube, and the other fed only at the top. Simple behavioral change made coexistence possible.
In both background and mass extinctions,
it's the same outcome for the species involved, but the causes tend to differ. In mass extinctions, the particular features of a species' biology don't really play a role in the extinction; rather, it's more like really bad luck. Background extinctions, by contrast, tend to be a consequence of one or more features of that particular species' biology.
variations in primary productivity
large based pyramid small based pyramid inverted pyramid
Large changes occur in response to
large changes in the environment, or new adaptation that allow for organism to thrive in new ways
Biomes:
large ecosystems that occur around the world
2) Local population size:
large versus small. Tigers and peregrine falcons, along with Welwitschia, a slow-growing, long-lived plant in southwest Africa, are examples of species that—as a consequence of their small population sizes—are at increased risk of extinction. With a small population size, a species is more susceptible to extinction due to a variety of factors that can kill individuals, including fire, disease, habitat destruction, and predation. Put simply, the more individuals that are alive, the more likely it is that some of them survive these events. With small population size, inbreeding is also increased, which generally reduces the fertility and longevity of individuals.
When a population grows exponentially at first but its growth slows as the population size approaches the environment's carrying capacity, the population growth is called
logistic growth and creates an S-shaped curve. Logistic growth is a much better approximation of how populations grow in the real world than exponential growth.
gymnosperms have successfully used wind pollination for
more than 200 million years
The evolutionary development of vascular tissue allowed
plants to grow larger.
There are three kingdoms of eukarya that can be seen with the naked eye:
plants, animals, and fungi. All are made up from eukaryotic cells—they have a membrane-enclosed nucleus—and each kingdom is almost entirely multicellular.
communities
populations of different species that interact with each other within a locale
Mimicry :
pretending to be another (more dangerous) organism
disruptive impacts: deforestation
problem: Tropical rain forests are being cleared at unprecendentedly high rates, endangering countless species and increasing the concentration of greenhouse gases in the atmosphere. Cause: the land is cleared for agriculture, logging, gold mines, and oil wells. Strategies for solution: reduced destruction of high-biodiversity habitats, particularly tropical rain forests
reducing CFCs
products made from ozone depleting CFCs, such as styrofoam hamburger boxes and hair sprays with damaging propellants, have been phased out in the hope of spurring a recovery of the ozone layer
The advent of molecular evidence (DNA in particular) suggests the most diversity was between
prokaryotes
We can get an idea of the appearance of the ancestral primate from the modern species of tree-living mammals called
prosimians—a group that includes lemurs.
Additional branching episodes in human evolution gave rise to
several species of advanced humans including Neandertals (Homo neanderthalensis) and our own species (Homo sapiens). This radiation coincided with an increase in body size to approximately the height and weight of modern humans, and an increase in brain volume to nearly twice that of earlier ancestors. In addition, the body form of the species that evolved during this episode looked like modern humans, with shorter arms and longer legs.
A small number of angiosperm species achieve pollination by
simply releasing their pollen to the wind, like the gymnosperms, or into water on the slim chance that through random luck, some of the pollen will land on the female reproductive organs of another plant. Given the astronomically low probability of any one pollen grain actually doing that, such wind and water pollinated plants respond in the only reasonable way: they produce tremendous amounts, in the tens of millions, of pollen grains per plant. Most angiosperms have a different way of moving pollen from the anthers of one flower to the stigma of another: they use animals to carry it.
Numerous factors that influence species richness are responsible for producing the tropical-to-temperate-to-polar gradient in biodiversity. Three, in particular, play strong roles:
solar energy available evolutionary history of an area rate of disturbance
factors that influence biodiversity
solar energy available evolutionary history of an area rate of disturbance
Bribery:
some plants offer something of value to an animal, bribing the animal to carry pollen from one plant to another. Here, a bee, covered in pollen, flies from flower to flower in search of nectar.
Hitching a ride
some seed pods have spines or projection that attach them to passing animals
the pace of evolution varies for different species.
some species have evolved gradually over time, while others spend vast amounts of time with little change
What is a seed?
structure: Fertilization produces a diploid seed, which contains a multicellular embryo and a store of carbs (endosperm) to fuel its initial growth Growth: a seedling draws energy from this endosperm while it extends its leaves upward to begin photosynthesis and its roots downward into the soil to reach water and nutrients
type 2 survivorship curve
survivorship decreases at a steady, regular pace
Other bacteria live
symbiotically with plants as small fertilizer factories, converting nitrogen into a form that is useable to the plant. Bacteria also give taste to many foods, from sour cream to cheese, yogurt, and sourdough bread. Increasingly, bacteria are used in biotechnology from those that can metabolize crude oil and help in the cleanup of spills to transgenic bacteria used in the production of insulin and other medical products.
For any given time in earth's history, it is possible to estimate the rate of extinctions at that time, and the evidence reveals
that these rates are far from constant (Figure 10-25 Extinction never sleeps). Although the particular details differ in most cases, extinctions generally fall into one of two categories: 1) "background" extinctions, or 2) mass extinctions.
Where once it was assumed that life could not survive,
the archeans not only exist, but thrive and diversify (Figure 10-31 Archaea can thrive in the most inhospitable-seeming places).
The trees Woese's genetic sequence data generated had some big surprises. First and foremost, the sequences revealed that
the biggest division in the diversity of life on earth was not between plants and animals. It wasn't even between prokaryotes and eukaryotes. The new trees revealed instead that the diversity among the microbes was dramatically greater than ever imagined—particularly because of the discovery of a completely new group of prokaryotes called archaea, which thrive in some of earth's most extreme environments and differ greatly from bacteria. The tree of life was revised to show three primary branches called domains: the bacteria, the archaea, and the eukarya (Figure 10-27 All living organisms are classified into one of three groups).
This ceiling on growth is
the carrying capacity, K, of the environment.
Viruses identify
the cells that they can infect by recognizing the structure of glycoprotein molecules on the surfaces of cells. Every cell in your body has these molecules. They are embedded in the plasma membrane and extend outward from the cell. Your immune system uses these proteins to identify the cells as part of you—as self rather than non-self—and it does not react to proteins that it recognizes as self.
succession
the change in species composition in a community over time
Angiosperms are
the dominant plants today.
female cone
the female cone has ovules on the protruding scales. they produce seeds when fertilized by pollen
eutrophication
the increase in nutrients in an ecosystem, particularly nitrogen and phosphorous, that often lead to the rapid growth of algae and bacteria in aquatic ecosystems. these large organisms then consume much of the O2, leading to large die-offs of animals.
Influenza Structure
the influenza virus has surface glycoproteins that allow it to bind to and exit a host cell
the values of biodiversity: intrinsic value
the inherent value of biodiversity, independent of its value to humans
male cone
the male cone releases pollen grains that require wind to reach a female cone
provisioning services
the many useful products that humans obtain from nature including food, pharmaceutical, and industrial products
Flowering plants (angiosperms) are
the most diverse and successful plants.
The advent of the seed was
the most important structure new to gymnosperms as it allowed for greater reproductive success
population oscillations
the snowshoe hare and lynx populations rise and crash in a 10 year cycle
Species interactions influence
the structure of communities.
Flying and floating:
the structure of some seeds allows them to be carried away from the parent plant by wind or water
Chemical Defenses
toxins, such as those found in strawberry poison dot frog, can make an organism poisonous or unpalatable to a predator Further prey defenses can include chemical toxins that make the prey poisonous or unpalatable. Plants can't run from their predators, so chemical defenses are especially important to them. Virtually all plants produce some chemicals to deter organisms that might eat them. The toxins can be severe, such as strychnine from plants in the genus Strychnos, which kills most vertebrates, including humans, by stimulating non-stop convulsions and other extreme and painful symptoms leading to death. At the other end of the spectrum are chemicals toxic to some insects but relatively mild to humans, such as those found in cinnamon, peppermint, and jalapeno peppers. Ironically, many plants that evolved to produce such chemicals to deter predators are now cultivated and eaten specifically for the chemicals they produce. One organism's toxic poison is another's spicy flavor. Some animals can also synthesize toxic compounds. The poison dart frog has poison glands all over its body, making it toxic to the touch. The fire salamander, too, is toxic, with the capacity to squirt a strong nerve toxin from poison glands on its back. Some animals, including milkweed bugs and monarch butterflies, are able to safely consume toxic chemicals from plants and sequester them in their tissues, becoming toxic to predators who try to eat them.
strategies for attracting pollinators
trickery bribery
1) In competitive exclusion,
two species battle for resources in the same niche until the more efficient of the two wins and the other species is driven to extinction in that location ("local extinction"). In the 1930s, this was demonstrated in simple laboratory experiments using Paramecium, a single-celled organism. Populations of two similar Paramecium species were grown either separately or together in test tubes containing water and their bacterial food source. When grown separately, each species thrived. When grown together, though, one species always drove the other to extinction.
With the same calculations,
we could determine the population size for the next 10 or even 50 years. When a population grows at a rate that is proportional to its current size—in other words, the bigger the population, the faster it grows—the growth is called exponential growth. The graph reveals that very quickly the size of a population growing exponentially becomes astronomical. In 10 years, our population would have grown from 500 individuals to 2580. In 50 years, it would reach almost 4 million. In fact, after 80 years, the population would pass one billion individuals. It's clear that exponential population growth ends badly.
invasive species: accidental introductions
-no natural predators, diseases, or parasites -other organisms in community don't have defenses for introduced species -introduced species may have life histories that can exploit new environment We don't have to look beyond the borders of the continental United States, though, to find examples of exotic species that are responsible for massive ecological shifts and economic costs. Purple loosestrife is an attractive flowering plant that is native to Eurasia. It was imported to the United States in the 1800s as a garden plant and rapidly escaped from cultivation and invaded wetlands in every state except Florida. It produces thousands of seeds a year and also spreads by sending out underground stems. This aggressive growth overwhelms native grasses, sedges, and flowering plants, replacing diverse wetland communities with monocultures of loosestrife that provide poor-quality habitats for bog-dwelling insects, birds, reptiles, amphibians, and mammals. The title of Most Destructive Invaders in North America may belong to the zebra mussels and quagga mussels. These thumbnail-size freshwater mussels are native to Eastern Europe and Western Asia. In the early 1800s, the mussels spread to Western Europe, and they came to North America in the 1950s, after completion of the Saint Lawrence Seaway allowed ocean-going ships to enter the Great Lakes. Female mussels produce up to 5 million eggs per year, and the larvae settle on any solid surface, even clogging the intake pipes of water-treatment plants and factories and the cooling systems of power plants.
Niche Features
-the space an organism requires -the type and amount of food an organism utlilizes -the timing of an organism's reproduction -an organism's temperature and moisture requirements and other necessary living conditions -the organisms for which it is a food source -its influence on competitors
Greenhouse effect
1. energy from the sun passes easily through the atmosphere to warm the earths surface 2. some energy is reflected back toward space and escapes the atmosphere 3. some energy is absorbed by greenhouse gases and remains trapped in the atmosphere, heating the air.
The nitrogen cycle
1. nitrogen gas, which has a chemical structure completely unusable by most organisms, is fixed by soil dwelling bacteria, producing ammonia and other compounds contacting nitrogen. 2. the nitrogen compounds are further modified by other bacteria into a form that can be taken up by plants and used to build new proteins along the way 3.nitrogen moves through the food chain as organisms eat plants and are themselves eaten. nitrogen is used by each organism to build new proteins along the way 4. animal wastes and dead animals and plants are broken down by soil bacteria that convert the nitrogen in tissue back to nitrogen gas. nitrogen gas returns to the atmosphere
the phosphorous cycle
1. plants absorb phosphorous through their roots int eh form of phosphate 2. phosphate moves through the food chain as organisms eat plants and are themselves eaten. phosphate is used by each organism to produce ATP and build DNA 3. phosphate returns to the soil when dead animals are broken down by bacteria and other decomposers 4. additional phosphorus is gradually released into the soil as rock is slowly weathered
the carbon cycle
1. plants use carbon molecules from atmospheric carbon dioxide and light energy from the sun to build sugars through photosynthesis 2. carbon moves through the food chain as organisms eat plants and are themselves eaten. organisms extract energy from carbon bonds and exhale co2 back into the atmosphere as a by-product 3. when large numbers of organisms die, carbon accumulates in the ground. over time, the organic remains can be transformed into coal, oil, and natural gas 4. burning coal, oil, and natural gas releases large amounts of carbon dioxide into the atmosphere
Demographic transition
1. slow growth: -birth rate: high -death rate: high -population growth: low 2. fast growth: -birth rate: high -death rate: low -population growth: high 3. slow growth -birth rate: low -death rate: low -population growth: low
On average, species persist for about
10 million years, although some last for hundreds of millions of years. In either case, when extinction occurs—the complete loss of all individuals in a species population—it is the end. And almost any way you look at biodiversity, from a utilitarian, aesthetic, or symbolic perspective, extinction is a tragic loss.
International cooperation and multiple strategies needed to address deforestation detailed
A large scale ecological problems will take international cooperation since ecosystems and their interactions with other ecosystems don't know borders, as well as one country many times influences the behavior of another country due to economic interdependence.
Developing countries
A more triangular shape is seen in the age pyramids of developing countries. Kenya, for example, has very high birth rates, reflected as a large base in its age pyramid. But high mortality rates, usually due to poor health care, cause a large and continuous reduction in the proportion of individuals in older age groups. In these countries, most of the population is in the younger age groups.
Viruses are not exactly living organisms.
A virus is not a cell, and that is why viruses do not fit into one of the three domains of life. A virus particle (called a virion) consists of genetic material inside a container made of protein. Some viruses also contain a few enzymes. That's all there is to a virus. They don't have a metabolism, reproduce on their own, maintain homeostasis within their body, don't respond to outside stimuli, and don't have the components that make up a cell proper. The protein container is called the capsid, and the genetic material can be either DNA (double sided) or RNA (single sided).
Energy and chemicals flow within ecosystems.
All life on earth is made possible because energy flows perpetually from the sun to the earth.
Evolution of the digestive tract
Allowed organisms to acquire more food while digesting previously acquired food Technically the digestive cavity is outside of our living body -A membrane is not crossed, "food" doesn't actually go inside a cell -Enzymes excreted, break down "food" to molecular components, absorbed through membranes into bloodstream
Why don't predators become so efficient at capturing prey that they drive the prey to extinction?
Although natural selection leads to predators with effective adaptations for capturing prey, the adaptations are rarely so efficient that the prey are driven to extinction. The explanation for this is referred to as the "life-dinner hypothesis." It generally holds true because selection for "escape ability" in the prey is stronger than selection for "capture ability" in the predator. When a prey, such as a rabbit, for example, can't escape from a fox, the cost is its life—and it will never reproduce again. On the other hand, when a fox can't keep up with a rabbit, all it loses is a meal; it can still go on to capture prey and reproduce in the future. In other words, the cost of losing in the interaction is much higher for the rabbit. If the predator is really good at catching the prey, eventually the prey will go extinct. With some species once populations become so low reproduction can crash because individuals can't find each other, or other important social interactions can't occur (passenger pigeon)
The fungi what are they most related to? What components?
Although they were originally thought to be plants lacking chlorophyll, it turns out that they have little in common with plants and, in fact, DNA sequence comparisons reveal that the fungi are more closely related to animals than they are to plants (Figure 12-29 Phylogeny of the fungi). As eukaryotes, fungi have all the basic cellular components you would expect to find: nuclei, mitochondria, an endomembrane system, and a cytoskeleton. They also have wall walls, but the cell walls, instead of including cellulose as plants do, are made of a protein called chitin, a chemical important in producing the exoskeleton of insects.
Global CO2 levels are rising overall, but they also exhibit a sharp rise and fall over the course of each year.
Although, on average, the level of CO2 in the environment is increasing, there is a yearly cycle of ups and downs in the CO2 levels in the northern hemisphere. This cycling is due to fluctuations in the ability of plants to absorb CO2. Many trees lose their leaves each fall and, during the winter months, relatively low rates of photosynthesis lead to low rates of CO2 consumption, causing an annual peak in atmospheric CO2 levels. During the summer, leaves are present, sunlight is strong, and photosynthesis (consuming CO2) occurs at much higher levels, causing a drop in the atmospheric CO2 level.
little brown bat
And some animals could not be farther from big bang reproduction, residing at the other end of the extreme. The little brown bat is also mouse-sized, yet does not reach maturity until one year of age and typically produces only a single offspring per year. It can, however, live more than 33 years its natural habitat.
aquatic biomes
Aquatic biomes are defined a bit differently, usually based on physical features such as salinity, water movement, and depth. Chief among these environments are 1) lakes and ponds, with non-flowing fresh water; 2) rivers and streams, with flowing fresh water; 3) estuaries and wetlands, where salt water and fresh water mix in a shallow region characterized by exceptionally high productivity; 4) open oceans, with deep salt water; and 5) coral reefs, highly diverse and productive regions in shallow oceans (Figure 15-4 Aquatic ecosystem diversity).
Ogallala Aquifer
Aquifers are areas underground that hold water due to the geology or the area. The Ogallala supplies much of the high plains with needed water for crops and ranching. Due to the economic and social consequence the USA has been monitoring it for about 30 yrs. Due to unsustainable practices it has been declining and threatens agriculture in the Midwest as well as the aquatic ecosystems that rely on springs from the Ogallala to survive. http://ne.water.usgs.gov/ogw/hpwlms/
Modern Preserve Design
As conservation biologists have started to better understand population dynamics and biogeography, the design of natural preserves has evolved. Using insights gained from the theory of island biogeography, modern preserve design focuses not simply on maximizing the variety of habitats and biodiversity preserved but on using several design features that maximize the efficiency of the preserves. Larger Circular Corridors Buffer zones
There is more than one way for populations to deviate from the standard population growth pattern. The explosive locust population growth just described occurs at unpredictable intervals. Another unusual pattern is the population oscillations of the lynx and snowshoe hare populations of Canada.
As seen in Figure 14-10 (Predator and prey), rather than smooth logistic growth, the populations of both the snowshoe hare and their predators, the lynx, have regular cycles between very large numbers and crashes to much smaller numbers. Thanks to the Hudson's Bay Company, which kept detailed records on the number of pelts it purchased from fur trappers, this population cycling is very well-documented. Although its cause is not fully certain, to some extent this predator and prey cause their own cycling: The hare population size grows, providing more food for the lynx, which then reproduce at a higher rate, causing them to eat too many of the hares, thereby reducing their food source, and causing the lynx population to crash, enabling the hare population to grow and the cycle to begin anew.
2) Keystone species.
As we saw in Chapter 15, keystone species have a disproportionate effect on the biodiversity of a community. Their removal can lead to massive changes in the composition of species in an ecosystem, often causing huge loss of biodiversity. Examples include kelp, California mussels, grizzly bears, beavers, and sea stars.
Microbes can live almost anywhere and eat almost anything.
As you read these lines, more than 400 species of microbes are thriving in your intestinal tract, 500 more species call your mouth home, and nearly 200 species live on your skin. The microbes that live in you and on you eat mostly what you eat—some of the bacteria in your mouth and intestine compete with you, trying to digest your food before you can, and the others use the waste products you release after you have broken down the food. Others feed on the leftovers released by the breakdown of your cells during the normal process of cell renewal. Living conditions in the human body are relatively moderate. Other microbes inhabit some of the toughest environments on earth—in the almost boiling water of hot springs, a mile below the earth's surface, and more than a mile deep in the oceans where hydrothermal vents emit water at 400°C (750°F).
Inside triangle:
Autotrophs are eaten by consumers, those consumers then die or produce waste that detrivores consume, that then produce their own waste which can be absorbed by autotrophs
Outside loop:
Autotrophs dies and is consumed by detrivores, some of those like beetles are eaten by consumers, additionally consumer waste such as CO2 respiration and nutrients in urine is absorbed by autotrophs
For any given time in earth's history, it is possible to estimate the rate of extinctions at that time, and the evidence reveals that these rates are far from constant (Figure 10-25 Extinction never sleeps). Although the particular details differ in most cases, extinctions generally fall into one of two categories: 1) "background" extinctions, or 2) mass extinctions.
Background extinctions are the extinctions that occur at lower rates during periods other than periods of mass extinctions. Background extinctions occur mostly as the result of natural selection. Competition with other species, for example, may reduce a species' size or the range over which it can grow. Or, a species might be too slow to adapt to gradually changing environmental conditions and become extinct as its individuals die off.
In the Pacific Northwest of the United States, a medium-size tree grows. This conifer, the Pacific yew tree (Taxus brevifolia), isn't the biggest tree in the forest, nor is it the most common.
But within the bark of the Pacific yew there is a chemical, called taxol, that has some important properties—it acts as an anti-mitotic agent, interfering with the division of cells that come into contact with it. The role taxol plays for the Pacific yew is not clear; it may reduce the rate at which other organisms feed on the plant. But in humans, taxol is effective in the treatment of ovarian cancer, breast cancer, and lung cancer (generating more than $1 billion a year in pharmaceutical sales).
the carbon cycle detailed
Carbon is found largely in four compartments on earth: the oceans, the atmosphere, terrestrial organisms, and fossil deposits. Plants and other photosynthetic organisms obtain most of their carbon from the atmosphere, where carbon is in the form of carbon dioxide (CO2). As we saw in Chapter 4, plants and some microorganisms utilize carbon dioxide in photosynthesis, separating the carbon molecules from CO2 and using them to build sugars. Carbon then moves through the food chain as organisms eat plants and are themselves eaten (Figure 15-16 Element cycling: carbon). The oceans contain most of the earth's carbon. Here, many organisms use dissolved carbon to build shells (which later dissolve back into the water after the organism dies). Most carbon returns to its reservoir as a consequence of organisms' metabolic processes. Organisms extract energy from food by breaking carbon-carbon bonds, releasing the energy stored in the bonds, and combining the released carbon atoms with oxygen. They then exhale the end product as CO2.
Why is competition hard to see in nature?
Competition between species has one very odd feature: it is very hard to actually see it occurring because it causes itself to disappear. That is, after only a short period of competition, either one of the species becomes locally extinct or leaves the area where the niches overlap, or character displacement occurs, largely reducing the competition. In either case, the net result is that the level of competition is significantly reduced or wiped out altogether. For this reason, biologists often have to look for character displacement—the "ghost of competition past"—to identify areas where competition has occurred in the past. Moreover, even while it is occurring, competition tends to be indirect, rather than head-to-head battles, therefore making it hard to identify.
biodiversity hotspots
Conservation biologists are increasingly interested in biodiversity hotspots, those regions of the world having significant reservoirs of biodiversity that are under threat of destruction. Twenty-five biodiversity hotspots have been identified around the globe that, while covering less than 1% of the world's area, have 20% or more of the world's species. Habitats included among the biodiversity hotspots are tropical rain forests, coral reefs, islands, and deep oceans.
Take-home message 16.14 conservation
Conservation biology has focused, in the past, on preserving individual species. Increasingly, there has been a shift toward the preservation of important habitats, focusing on conserving communities and ecosystems. Taken together, the strategies used by conservation biologists represent an important step toward reducing the adverse effects of one hugely successful (from a growth perspective) species—humans—on other species. Although we are far from living with minimal perturbation of the environment in which we live, continued conservation efforts offer our best hope for a sustainable future.
Natural Resource Management detailed
Consider a situation that many natural resource managers encounter. Suppose that a population of organisms with great value appears to be threatened by the predatory behavior of another species. To protect the valuable population, the natural resource manager might be tempted to intervene, blocking the predator from harming the valuable population. This seems like a reasonable plan. But how can we be sure? In fact, our plan, with all its good intentions, may not work. Worse, it may have exactly the opposite effect of what we intend. Example: a biologist visiting Africa observed an intervention that was in place to help a plant species— acacia trees. The intervention: large groups of these trees were fenced off to protect them from the destructive herbivory of elephants and giraffes.
Three key distinctions divide the animals that we'll look at
Does the animal have specialized cells that form defined tissues? 2) Does the animal develop with radial symmetry or bilateral symmetry? 3) During gut development, does the mouth or anus form first? 4) Exclude molting v. non-molting
3) During gut development, does the mouth or anus form first?
Early in the evolution of animals—about 630 million years ago—a major split occurred that allows us to separate the bilaterally symmetrical animals with defined tissues into two distinct lineages: the protostomes (which can be translated as "mouth first") and the deuterostomes ("mouth second"). These names refer to the way the gut develops—from front to back or from back to front. In protostomes, the gut develops from front to back, so the first opening that forms becomes the mouth of the adult animal, and the last opening becomes the anus. In deuterostomes, the gut develops from back to front. The anus is the first opening to form, and the second is the mouth.
Take-home message 15.7 pyramids
Energy pyramids reveal that the biomass of producers in an ecosystem tends to be far greater than the biomass of herbivores. Subsequently the biomass of the herbivores is greater than the carnivores
mass extinctions
Extreme changes to the environment a large number of species become extinct over a short period of time due to extraordinary and sudden environmental change
Nutrients are like a bottleneck limiting plant growth.
Fertilizers: Nitrogen (N) and Phosphorus (P) Because it is necessary for the production of every plant protein, and because all nitrogen must first be made usable by bacteria, plant growth is often limited by nitrogen levels in the soil. For this reason, most fertilizers contain nitrogen in a form usable by plants.
Almost all natural resource managers working for the U.S. government fail to do their job exactly as mandated. Why? What's the better solution?
For long-term management, it is better to harvest some but leave others still growing and reproducing for harvest at a later time. With such a strategy, the population can persist indefinitely. The special case, in which as many individuals as possible are removed from the population without impairing its growth rate, is called the Maximum Sustainable Yield. The value in such a harvest comes from the fact that it can be carried out forever, clearly yielding more than the short-sighted strategy of a complete harvest. Your first step as the manager is to determine the maximum sustainable yield for the resource, calculated as the point at which the population is growing at its fastest rate. If we examine the logistic growth curve, we can see that the population is getting larger at the fastest rate when it is equal to half of the carrying capacity. At this midpoint, scarcity of mates is not a problem as it can be at low population levels, and competition is not a factor as it can be near the carrying capacity—one of the reasons why the population doesn't grow at all when it is at its carrying capacity. Maximum sustainable yield is a useful concept, applicable not just to wood harvesting but also to livestock, agriculture, and nearly every other useful natural resource. And, in fact, there are 31 official U.S. agencies that, in their charters, are mandated to utilize the maximum sustainable yield concept in determining their harvest levels. But here's the rub: This is nearly always an impossible task.
Captive breeding programs and habitat restoration detailed
For more critically endangered species and degraded habitats, all hope is not necessarily lost. Captive breeding programs and habitat restoration have had some success in bringing back biodiversity from the brink of extinction. Zoos and botanical gardens have taken the lead in many of these efforts. In the 1980s, for example, when the population size of the California condor had dropped to 22 individuals, due to poaching, lead poisoning, and habitat loss, all of the birds were caught and taken to zoos, where a captive breeding program began. With the success of these breeding programs, by 2009, more than 100 birds have been released back into the wild, and more than 150 more are in zoos. Breeding programs are not a complete conservation solution on their own, however. It is essential that the species' habitats are not destroyed or altered if the species are to flourish again under natural conditions.
And the problem gets worse.
For one thing, with many species, not only do we not know carrying capacity, we don't even know the number of individuals alive. It is even difficult to accurately count humans, so imagine how hard it is for a species in which the individuals are underwater or fly or are microscopic. And if we were to solve the mysteries of counting individuals and knowing carrying capacity, we would still have to figure out whether carrying capacity is stable from year to year. If carrying capacity depends on levels of resources, it may be cyclic, for instance. And even with knowledge of carrying capacity and population size, we would not be certain which individuals ought to be harvested. Often the individuals in a population are not contributing equally to population growth. The post-reproductive individuals mentioned above, for example, do not contribute to population growth. As a natural resource manager you do your best, knowing that the theory behind the concept of maximum sustainable yield can almost never be put into practice perfectly.
reducing CFCs detailed
Fortunately, the worldwide response to the dangers accompanying creation of the ozone holes is an encouraging example of effective integration of science and policymaking. When CFCs were first invented, they were considered harmless, and so their use as coolants, as aerosol propellants, and in the production of materials such as Styrofoam became widespread. But the recognition that CFCs eventually reach the highest levels of the atmosphere and catalyze the destruction of the protective ozone layer prompted relatively quick reaction and efforts to find solutions. With the adoption by most countries, in the 1980s, of an agreement to discontinue the use of CFCs, ozone depletion was slowed. And in 2010, scientists found that the atmospheric levels of ozone had stabilized. A full recovery could occur by 2050.
The Endangered Species Act
From locale to locale the particulars of these questions may change, but the underlying issue remains: in a world where species are being driven to extinction faster than we can save them, which should be singled out for preservation and which should we leave to almost certain extinction (Figure 16-33)? This is a question that biologists, policymakers, and, ultimately, citizens must address. In the United States, much conservation policy involves response to the Endangered Species Act (ESA). The law is designed to protect these species from extinction. Species that are dwindling are listed as endangered or threatened, according to an assessment of their risk of extinction. Once a species is listed, legal tools are available to help rebuild the population and protect the habitat critical to its survival.
what recycles detritus?
Fungus, bacteria, and many different animals all recycle detritus. This releases nutrients (N,P)
How do we measure biodiversity?
Go out a count organisms (almost that simple) Species Richness: Species Diversity:
Q: How did the pronghorn become so fast?
H: There is/was a predator in N.A. that could out maneuver pronghorns long enough to influence their evolution. P: If (H), then there will be fossil evidence of predators with physical characteristics allowing them to catch pronghorns.
The Homo sapiens who migrated through the Indo-Australian Archipelago encountered two species of humans, Homo erectus and Homo floresiensis.
Homo erectus had migrated to Asia at least a million years earlier, and was still present on the island of Java when modern humans arrived about 50,000 years ago. Although H. erectus was the same size as modern humans, it had a smaller brain (an average brain volume of just over a quart [about 1000 cubic centimeters] for H. erectus compared to a quart-and-a-half [about 1400 cubic centimeters] for H. sapiens). Nonetheless, Homo erectus had technological skills. They may have been the first humans to use fire (the evidence is not definitive about this), and they almost certainly built boats that allowed them to move along coasts and from island to island. In 2003 stone tools and fossils of a species of human only 3 feet (about 1 meter) tall and with a brain volume of just over a pint (about 350 cubic centimeters) were discovered on Flores Island, which lies east of Java. The paleontologists who discovered this species gave it the scientific name Homo floresiensis ("Flores man"), but the world press promptly called it the Hobbit because of its tiny size. At the time that the dwarf human Homo floresiensis lived, Flores Island was also home to a dwarf elephant—which Homo floresiensis probably ate—and a giant monitor lizard that probably ate Homo floresiensis.
The Indo-Australian Archipelago
Homo erectus: roughly the same size, smaller brain, used technology, boats to move from island to island Homo floresiensis: discovered in 2003, 3 ft. tall (hobbit people) -Flores Island -Lived until 12,000 years ago
Biogeochemistry
How different organisms, including you, are linked over time and across geographic space by chemical interactions (Nitrogen and Phosphorous) Changing the chemical balance of an ecosystem changes the biological balance Damaged ecosystems can be repaired to some extent
Species Richness:
How many different species present in a community. Simply the more species you have the higher the Species Richness
Carboniferous Period
Huge fern forests dominated the earth Gymnosperms, non-flowering seed bearing plants, were just starting to dominate No fungus or bacteria yet evolved to eat/decompose cellulose If nothing could break down the plant matter 300 mya then what happened to all those dead plants?
mycorrhizae
If you examine the roots of a plant with a microscope, you will find round structures and fibers closely associated with the fine rootlets and root hairs. These are root fungi, or mycorrhizae. Some mycorrhizae have hyphae that press closely against the walls of root hair cells. Others send hyphae through the root cell walls and into the space between the cell wall and the plasma membrane (Figure 12-34). Beneficial associations between roots and fungi are ancient—they have been found in 400-million-year-old fossils of early land plants—and nearly all species of modern plants have them.
Captive breeding programs and habitat restoration
Bringing back biodiversity from the brink of extinction Zoos and botanical gardens Restoration Ecology -Natural habitat is essential
Microbes
Can Live Almost Anywhere and Eat Almost Anything
The Three Most Important Element (Chemical) Cycles
Carbon Nitrogen Phosphorus
N.A. had populations of
Cheetahs and long legged Hyenas until ~12,000 ya
International cooperation and multiple strategies
...are needed to address the problem of tropical deforestation.
• Buffer zones
(which permit limited amounts of human activity) around core areas (which contain the habitat to be conserved)
Take-home message 13.16 viruses
A virus takes over the protein-making machinery of the host cell to produce more viral genetic material (RNA or DNA) and protein. The viral proteins and genetic material are assembled into new virus particles and released from the cell.
four kingdoms. Plants, Animals, Fungi, and Protists
All are made up from eukaryotic cells—they have a membrane-enclosed nucleus—and each kingdom is almost entirely multicellular.
Dissolved Oxygen
All gases can be dissolved in a liquid -Think of soda pop All aquatic heterotrophs need high enough dissolved oxygen levels to breathe -Some bacteria can live with little to no oxygen levels, while many larger organisms can't live below 5 mg DO/L
4. Increased number of competitor ants → increase in stem-boring beetles and plant damage.
The competitor, non-mutualistic ants encouraged beetles to infect the plants: the beetles bored cavities in the acacia stems, where the competing ants could lay eggs. And when beetles bore cavities, plants suffer. The researchers documented that acacia growth was much slower, and mortality was doubled.
The evolution of plants
The earliest land plants were the first multicellular organism to live on land; these simple non-vascular plants had no vessels to transport water and nutrients. They did produce a cuticle, a waxy substance, to prevent the loss of water though. The subsequent evolution of land plants was a series of radiations of forms with characteristics that made them increasingly independent of water. Although fungi are not plants, they are very closely associated with plants.
2) Evolutionary history of an area.
Communities diversify over time. Consequently, the more time that passes, generally speaking, the greater the diversity in an area. A high level of biodiversity in an area, however, can be knocked back down by climatic disasters such as glaciations. This biodiversity decline may occur in temperate and polar regions.
common characteristics of the angiosperms
Distribute water and nutrients throughout the plant with a circulatory system of vascular tissue Produce flowers which produce gametes Seeds are enclosed within an ovary
Native invasive:
Disturbance gave a local species an reproductive advantage (algae and nutrient pollution)
Anthropocene: The period of humans
Earth history periods (Jurassic, Triassic, Cambrian, etc) are all defined by dramatic biological and/or abiotic changes. -Humans have created large abiotic changes (green house gases and subsequent warming, changes in acidity of water and soils, altered nutrient balances, huge landscape changes, foreign chemicals poisoning large areas, etc. ) -Biological changes influenced by over harvesting/ hunting, introduction of exotic invasive species. Biologic changes are influence by abiotic changes as well.
Energy Flow
Energy from the sun passes through an ecosystem in several steps known as trophic levels. Losses at every "step" in a food chain -Inefficiency of energy transfers -Organisms don't fully digest everything -Most energy is used in respiration, not building the organism (biomass)
Efforts Focusing on Individual Species
Flagship species: Iconic, beautiful Keystone species: Ecological Importance Indicator species: Sensitive to disturbance Umbrella species: By protecting this specie other species are indirectly protected
terrestrial biomes
For example, where it is always moist and the temperature does not vary across the seasons, tropical rainforests develop. And where it is hot but with strong seasonality that brings a "wet" season and a "dry" season, savannas or tropical seasonal forests tend to develop. At the other end of the spectrum, in dry areas with a hot season and a cold season, temperate grasslands or deserts develop. Figure 15-3 (Terrestrial ecosystem diversity) shows examples of the nine chief terrestrial biomes; all are determined, in large part, by the precipitation and temperature levels.
seed dispersal
Hitching a ride Flying and floating: Providing a food source:
Opened in 2015, first time since it was established in 2008
Lebanese company based in Syria lost its seed bank in 2012 The company donated 325 boxes of seeds, requested 125 returned Will be used to reestablish crops in areas affect by war within the Fertile Crescent They were not sent back to Syria, and it is a secret as to where they were sent
We can get an idea of the appearance of the ancestral primate from the modern species of tree-living mammals called prosimians—a group that includes lemurs.
Many of the anatomical characteristics of humans and the other primates can be traced to our arboreal origin. Our forward-directed eyes and binocular vision that allows us to judge distances accurately, our shoulder and elbow joints that allow our arms to rotate, and the retention of ten fingers and ten toes that allow us to grasp objects are traits we inherited from arboreal ancestors.
Feedback loops
Many times positive feedback loops throw ecological systems out of balance, though not always. One exception is primary succession. The establishment of organism start the creation of soil, which helps the establishment of other organisms which in turn contribute to the establishment of soil and new organisms.
Invasive:
Means that the species has the potential to take over a niche
Exotic:
Means the species is foreign
Take-home message 13.1 microbes
Microbes are grouped together only because they are small, not because of evolutionary relatedness. They occur in all three domains of life and also include the viruses, which are not included in any of the domains. 500,000 determined. Millions more expected to be discovered with the advancement of genetic analysis
Mitochondrial DNA shows that the initial human migration out of Africa followed three major pathways.
One path turned west after leaving Africa and spread into Europe. A second path turned southeast and spread into southern Asia and through the Indo-Australia Archipelago to Australia. The third migration moved northeast, populating northern Asia. This is the group that crossed the Bering Straits bridge about 15,000 years ago and spread southward through the Americas.
Heterotrophs breakdown organic molecules
Organic (Living tissue, detritus, soil) -Nutrients (N or P) are locked in many different large organic molecules (protein, membranes, DNA, ATP, etc) -Low water solubility, therefore reduced mobility in the landscape -Inaccessible to primary producers for uptake, must be released (converted to inorganic) by heterotrophs Inorganic -Very small in size (ex. NH4, NO3, NO2, PO4) -High water solubility. Therefore high mobility -Accessible to primary producers for uptake
Take-home message 15.7 biomass
Similarly, the biomass transferred at each successive step in the food chain tends to be only about 10% of the biomass of the organisms consumed. Due to this inefficiency, food chains rarely exceed four levels. (in terrestrial systems)
Example of bacteria doing work for free.
Since oil has a lot of potential energy some bacteria were able to utilize this energy source and was able to breakdown much of the oil.
Why would the male dying soon after copulation, and then the female dying after reproduction increase fitness of the species
Some animals reproduce with a "big bang." Antechinus is an Australian mouse-sized marsupial, and the males are classic big-bang reproducers. At one year of age, they enter a two- to three-week period of intense mating activity, copulating for as much as 12 hours at a time. Shortly after this mating period, the males undergo rapid physical deterioration—they lose weight, much of their fur falls out, their resistance to parasites falls—and then die.
disruptive impacts: increased greenhouse gas emissions detailed
Some of the evidence that the earth's atmosphere is warming comes from weather records that extend back into the 1700s. Those records show that the average temperature has increased rapidly during the past 50 years and that 18 of the 20 hottest years on record have occurred since 1990. Data from a report on Antarctic ice cores, published in the journal Science in 2007, extend the temperature records back to more than 800,000 years ago.
1. Does the animal have specialized cells that form defined tissues?
Sponges do not, all other animals form a monophyletic group of animals with clearly defined tissues. Humans, for example, have highly specialized cells such as skin cells, muscle cells, and sensory cells.
The traditional model of how evolutionary change occurred was that used in the previous section to describe microevolution. Populations changed slowly but surely, gradually accumulating sufficient genetic differences for speciation—hence the phrase "evolution by creeps."
Spurred on by findings from the fossil record that do not always support this view, however, researchers have come to believe that evolution may commonly occur in brief periods of rapid evolutionary change right after speciation, followed by long periods with relatively little change—hence "evolution by jerks."
Fungi make up their own
monophyletic kingdom within the Eukarya domain. Most fungi are multicellular, sessile decomposers.
Fungi and plants are
partners but not relatives
Mechanical Defenses
physical structures can help protect an organism from predation Predation plays a large role in producing adaptations such as the sharp quills of a porcupine, the prickly spines of a cactus, the wings of a bird or bat, or the tough armor protecting an armadillo or sow bug. These features, as well as claws, fangs, stingers, and other physical structures, can reduce predation risk.
Niche:
place or role in the environment for a species
In an environment in which these "bad luck" events repeatedly occur, a
population might never have time to grow as high as the carrying capacity. Instead, it might perpetually be in a state of exponential growth, with periodic massive mortality events. The population's growth would appear as a series of jagged curves.
disruptive impacts: acid rain
problem: acid precipitation kills plants and aquatic animals directly, and also acts indirectly via changes in soil and water chemistry cause: burning fossil fuels releases sulfur dioxide and nitrogen dioxide. the compounds form sulfuric and nitric acids when combined with water vapor. strategies for solution: tighter regulation and reduction of SO2 and NO2
Moving onto land presents challenges
problem: gravity problem: desiccation
disruptive impacts: increased greenhouse gas emissions
problem: the avg temp has increased rapidly in the past 50 years, affecting both the physical env and the biological world cause: burning fossil fuels and clearing land to cultivate crops have significantly increased levels of greenhouse gases in the atmosphere strategies for solution: reduced emissions of greenhouse gases (particularly from the burning of fossil fuels)
A fourth kingdom contains the
protists, which are often too small to be seen by the naked eye, and is a sort of grab bag that includes a wide range of mostly single-celled eukaryotic organisms, including amoebas, paramecia, and algae. As we noted earlier, biologists now know that the protists are not a monophyletic (single) group and are increasingly splitting them into multiple kingdoms within the eukarya.
14.3 Populations can grow
quickly for a while, but not forever.
• Circular,
rather than linear, preserves
• Larger,
rather than smaller, preserves (including a preference for a single, undivided preserve over several smaller preserves)
Lichens are
really two organisms living together. A fungus and either an algae or bacteria which are both photosynthetic. Because the two species are always found together we can name the lichens as singular organisms.
small-based pyramid
reduced ability to support consumers common in deserts, tundras, and open oceans
Biota:
refers to the living components of the ecosystem
Variation for a trait:
running speed in rabbits can vary from one individual to the next
Gymnosperms are
seed bearing plants
two types of pollination
self pollination cross pollination
inverted pyramids
small biomass of producers supports a relatively large biomass of consumers occurs in some aquatic ecosystems where plankton are producers
large based pyramid
supports a relatively large biomass of consumer common in rain forests, marshes, and algal beds
Roughly 30-40 years ago a culture of gut bacteria was
taken from just one portion of the digestive tract, and then they used that to extrapolate a number for the whole digestive tract. Unfortunately that one part was much higher in bacteria and not representative of the whole digestive tract. Therefore it was thought for decades that many more bacteria live in our gut, and a perfect example of the pitfalls when experiments are not retested and scrutinized.
The traditional model of how evolutionary change occurred was
that used in the previous section to describe microevolution. Populations changed slowly but surely, gradually accumulating sufficient genetic differences for speciation—hence the phrase "evolution by creeps."
The most commonly encountered types of fungi are
the 1) yeasts (the only single-celled fungi), truffles, and morels of the phylum Ascomycota; 2) mushrooms, of the phylum Basidiomycota; and 3) molds (which are not a phylogenetic grouping), such as Penicillium—the source of the antibiotic penicillin—of the phylum Ascomycota, and black bread mold, of the monophyletic phylum Zygomycota (FIGURE 12-30).
cultural services
the aesthetic, symbolic, and spiritual values of biodiversity, as well as scientific and educational value
In each case there has been strong coevolution between the plants and their pollinators:
the plants get more and more effective at attracting the pollinators and deterring other species from visiting the flower, whereas the pollinators get more and more effective at exploiting the resources offered by the plants.
16.12 Reversing ozone layer depletion illustrates
the power of good science, effective policymaking, and international cooperation.
Throughout his writings, for the many species he described, Darwin emphasized
the process of adaptation and the relationship between populations of organisms and the environments in which they lived. One species was never better or worse than another. Rather, each species was differentiated from the others, with specializations that adapted individuals of that species to the particular niche in which they lived. Different environments posed different challenges. All extant species, as evidenced by their existence and persistence, are able to overcome those challenges.
The next big innovation in plant evolution was
the seed, an embryonic plant with its own supply of water and nutrients encased within a protective coating.
Population ecology:
the study of how populations (of a species) interact with their environments.
Heritability:
the trait of running speed is passed on from parents to the their offsring
habitat services
the value to humans from soil formation, photosynthesis, and nutrient cycling
regulating services
the values that come from the regulation of our environment, including climate regulation, waste decomposition, protection from natural disasters, and pest and disease control
Microbes occur in all three domains of life—bacteria, archaea, and eukarya—and so
the various types of microbes could not be more widely separated.
background extinctions
these extinctions occur at lower rates during times other than mass extinctions occur mostly as the result of natural selection
Global CO2 levels are rising overall, but
they also exhibit a sharp rise and fall over the course of each year.
As land plants emerged,
they faced the same two challenges that were to confront the first terrestrial animals, some 25 million years later: supporting themselves against the pull of gravity and reducing evaporation so they didn't dry out. The second of these problems was the more urgent. The earliest plants did not have to grow upward—they could creep along the ground—but they did have to avoid drying out (Figure 12-6). The material that protects all land plants from drying is a shiny, waxy layer on the stem and leaves called the cuticle.
Around the world, countries vary tremendously in the age pyramids describing their populations. If two populations are the same size but have different age distributions,
they will have some very different features.
The glycoproteins on the surface of a virus determine
what host species the virus can infect and which tissues of the host the virus can enter. Influenza A viruses (the ones that cause outbreaks of flu every year), for example, have two types of glycoprotein that have different functions. One glycoprotein matches that of a host cell, and allows the virus to enter the cell. The other glycoprotein allows the virus to get back out of the cell, releasing new virus particles that can infect other cells.
Restoration ecology,
which uses the principles of ecology to restore degraded habitats to their natural state, has also been an important tool of conservation biologists. Wetlands that have been degraded by dredging and development, in particular, have benefited. Reintroduction of the native plant species and restoration of water and stream flow patterns can be instrumental in restoring these habitats.
Evolutionary innovations.
with the evolution of an innovative feature that increases fitness, a species can rapid diversify
Mass extinction events.
with their competition suddenly eliminated, remaining specieis can rapidly diversify
The disappointing but unavoidable implication is that,
within an ecosystem, seemingly helpful, straightforward manipulations may have significant, negative consequences. Large herbivores serve a very important regulatory role in the ecosystem, similar in some ways to a large predator but through different means. Ecosystems are extremely complex and we are just beginning to understand the complexity in which the parts are interconnected. Understanding the parts is the first step to maintaining it.
Many of the early flowering plants
would look familiar to us, and angiosperms dominate the plant world now, with some 250,000 species compared to the approximately 800 species of gymnosperms.
How many people can earth support? Why does the answer keep increasing?
The growth of populations doesn't always appear as a smooth S-shaped logistic growth curve. For some populations, particularly humans, the carrying capacity of an environment is not set in stone.
Why is that so?
There are numerous reasons. For starters, if maximum sustainable yield occurs when a population is half its carrying capacity, do we first have to wait until the population stabilizes at its carrying capacity to determine what half of the carrying capacity was? But isn't it inefficient to sit around waiting for the population to reach its carrying capacity when you want to maintain it at half that size? Or can you just estimate carrying capacity in order to calculate half of it? But that can be difficult since lobsters live underwater? Put simply, we rarely know the value of K.
16.12 Reversing ozone layer depletion illustrates the power of good science, effective policymaking, and international cooperation.
There are two types of "ozone depletion": the general reduction in the amount of ozone in the stratosphere and the formation of areas with very low ozone concentration (called "ozone holes") over the North and South Poles every winter. Synthetic chemicals known as chlorofluorocarbons (CFCs) are the villains in both forms of ozone depletion. CFCs, which were developed in the 1930s, have a wide range of applications, including use as coolants in refrigeration systems.
There is a fundamental difference between background and mass extinctions that goes beyond differences in rates.
They have different causes. Mass extinctions are due to extraordinary and sudden changes to the environment (such as the asteroid that brought about the dinosaurs' extinction). As a consequence, nothing more than bad luck is responsible for the extinction of species during mass extinctions; fit and unfit individuals alike perish.
what were these plants like?
They weren't impressive looking—just some patches of low-growing green stems at the water's edge. They did not have any of the structures we associate with plants today—no roots, leaves, flowers. But from an evolutionary perspective, those early plants were enormously important because until terrestrial plants evolved there was nothing on land to eat. Thus, the first land plants not only set the stage for the tremendous diversity of plants we know today, but also paved the way for the evolution and diversification of land animals.
Biological systems are also showing the effects of climate change. detailed
Trees and flowers in northern latitudes are blooming earlier in the spring than they used to; migratory birds are arriving at their summer ranges earlier than they did even a decade ago; and birds and butterflies are extending their geographic ranges northward. The changes to the physical environment caused by global warming, such as thinning of the Arctic Ocean ice or the flooding of coastal estuaries, can have profound effects on biodiversity at the species and ecosystem levels. Other consequences of global warming reveal the tremendous interconnectedness of so many elements of ecosystems.
1) Reducing biodiversity.
Tropical rain forests of Africa, Asia, the Pacific, and Central and South America contain an unusually large number of species of plants and animals (and probably other taxa).
Fungi have an unusual and effective method of getting nutrition.
Unlike humans, they digest their food outside of their "body." While growing underground, hyphae secrete strong enzymes that break down the organic molecules around them. They then absorb those nutrients.
Positive feedback loop:
When "A" causes "B", and "B" promotes or increases "A" Warmer temps melting ice caps which reduces reflectivity and increases water temp, which melts more ice which reduces reflectivity...etc.
Negative feedback loop:
When "A" causes "B", but "B" reduces or limits "A". When my body gets too hot I sweat, sweating reduces heat within my body to where I don't sweat
The archaea are still grouped
all in one kingdom within the domain archaea, but we have no idea how many species exist. Given that archaea are the dominant microbe in the deep seas, it may very well be that these organisms of which we were completely ignorant are the most common organisms on earth. It is still too early to tell. Because they thrive in many habitats that humans have not yet studied well, including the deepest seas and oceans, they may turn out to be much more common than currently believed.
ecosystems
all living organisms, as well as non-living elements, that interact in a particular area
In many situations, resource partitioning is accompanied by character displacement,
an evolutionary divergence in one or both of the species that leads to a partitioning of the niche. A clear example occurs among two species of seed-eating finches on the Galápagos Islands. On islands where both species live, their beak sizes differ significantly. One species has a deeper beak, better for large seeds, while the other has a shallower beak, better for smaller seeds, and they do not compete. On islands where either species occurs alone, beak size is intermediate between the two sizes.
Fungi are closer to
animals than they are to plants.
all ecosystems share two essential features
biotic environment physical (abiotic) environment
In nature, there are examples of
both gradual change and the irregular pattern of punctuated equilibrium. It's not a situation in which one version is right and one is wrong. Punctuated equilibrium may be more influential to adaptive radiation after major changes to the situation the organism finds itself in.
mutualism
both species benefited
competition
both species have an undesirable effect
Nutrients are like a
bottleneck limiting plant growth.
12.11 Fleshy fruits are
bribes that flowering plants pay animals to disperse seeds.
physical defenses for reducing predation
camouflage chemical defenses warning coloration
Inorganic: Organic:
can fertilize 3 times can only fertilize once
-Fungus have chitin
cell-walls, which is the same material in the shells of insects
Communities can
change or remain stable over time.
Vascular plants could
colonize areas where the soil at the surface of the ground was not always wet, because their roots could penetrate the soil to reach water and nutrients.
This competition doesn't last forever, though. Inevitably, one of two outcomes occurs:
competitive exclusion or resource partitioning.
The four tallest trees in the world are The oldest tree trunk belongs to
conifers a Great Basin bristlecone pine. The current record holder, the Methuselah tree, has lived for more than 4800 years and a slightly older tree was cut down in 1964.
The biotic environment
consists of all the living organisms within an area and is often referred to as a community.
Many angiosperms make a fleshy fruit that
consists of the ovary plus some additional parts of the flower. For example, the core of an apple is the ovary and the flesh of the apple is derived from adjacent parts of the flower. Blueberries, watermelons, oranges, tomatoes, and peaches are other examples of fleshy fruits.
Bacteria that can
convert nitrogen gas (N2) to fertilizer (NO3) live in the root nodules. What kind of relationship is this and why? Alfalfa is used during crop rotation to replenish the N in the soil of crop fields.
logistic growth equation
dN/dt = rN((K-N)/K)) As "K" approaches "N" then the (K-N) term approaches zero dN/dt = new individuals over time As (K-N) gets closer to 0, the whole right side approaches 0
Detritus:
dead material and waste from other organisms, junk that many organisms can't digest
Antarctic Ozone Depletion
depletion of the ozone layer and the formation of an ozone hole over earths polar regions have occurred as a result of human activities
Element cycling (C,N,P)
detrivores --> autotrophs --> consumers --> detrivores cycle
A virus particle
does not carry out any metabolic processes, and it does not control the inward or outward movement of molecules to make conditions inside the virus particle different from conditions outside. Viruses just wait for a chance to insert their genetic material into a living cell.
Pea pods, sunflower seeds, corn kernels, and hazelnuts are fruits. These fruits are called
dry fruits, and the seeds they contain are transported by wind or water or by sticking to an animal.
Analyses of DNA and RNA sequences have helped biologists to
identify four key distinctions into which we can group all of the animals. Each of these distinctions hinges on a particular adaptation, and the question of whether an animal descends from an ancestor with the adaptation.
Differntial reproductive success:
in a population, rabbits with slower running speeds are eaten by the fox, and their traits are not passed on to the next generation
This newer view of the pace of evolution,
in which rapid periods of evolutionary change are punctuated by longer periods with little change, is called punctuated equilibrium.
In addition to being abundant, diverse, and widespread, the cone-bearing trees, specifically the conifers,
include both the tallest and the oldest living organisms on earth.
individuals
individual organisms
Soil
is considered a living component of ecosystems, as long as it hasn't been paved over or has been severely disturbed
Climate:
is most influence by precipitation and temperature
Biodiversity
is the variety of genes, species, and ecosystems on earth. There is tremendous value that can come from earth's biodiversity, and the loss of biodiversity can be hugely detrimental to humans. Additionally, the United Nations has asserted that biodiversity has an intrinsic value—that is, an inherent value independent of its value to humans. Many religions highlight that humans have the responsibility of stewardship of the earth, so this idea isn't new.
A flower is nothing without
its pollinator;
Most viruses
kill their host cells upon release of newly made viruses
Consequences of the loss of biodiversity, beyond the values of biodiversity discussed earlier, are
largely unknown, but most likely include a serious reduction in the capacity of the environment to recover from environmental and human-induced disasters.
The fleshy part of a fruit is often
larger than the ovary, and a plant invests a lot of energy in producing fleshy fruit. The payback comes when an animal eats the fruit and then defecates the seeds at a location that is removed from the parent plant. In other words, fleshy fruit is the bait that some flowering plants use to get animals to disperse their seeds.
secondary succession
like primary succession with a head start. begins with a disturbance opens up part of the community to the development and growth of species previously outcompeted by other species in the area
density independent factors
limit population size
Density-dependent Factors:
limitations on a population's growth that are a consequence of population density reduced food supplies due to competition diminished accessibility to places to live and breed due to competition increased incidence of parasites and disease increased predation risk
slow, gradual reproductive investment
little brown bat reaches sexual maturity at one year produces about one offspring per year
Viruses are at the border between
living and non-living.
logistic growth
logistic growth describes population growth that is gradually reduced as the population nears the environment's carrying capacity
Excessive use of antibiotics in medicine and agriculture has
made several of the most important pathogenic bacteria resistant to every known antibiotic, and infections caused by these bacteria are nearly impossible to treat.
Fungus are a
major recycler of nutrients -breakdown old organic matter so living organisms can utilize the nutrients locked in the old organic matter
Heterotrophs,
many of them decomposers, breakdown organic material to release nutrients back into the environment for autotrophs to use again. The autotrophs convert inorganic molecules back into complex organic molecules (glucose, amino acids, nucleic acids, etc.) that will eventually be eaten by heterotrophs again.
The archaea domain includes
many species living in extreme environments.
Two categories of extinction
mass extinctions background extinctitons
Extinctions can be divided into two general categories:
mass extinctions and background extinctions. They're distinguished by the numbers of species affected. When a large proportion of species on earth are lost in a short period of time—such as when an asteroid struck earth 65 million years ago and about 75% of all species were wiped out—it's considered a mass extinction. These extinctions are above and beyond the normal rate of extinctions that occur in any given period of time, referred to as background extinctions.
The First Land Plants Appeared About
475 Million Years Ago
Exotic invasive: .
A foreign species that is invasive, no natural predators, other species haven't evolved defenses
This deforestation is devastating for two main reasons.
-Biodiversity -Rainforests absorb the most carbon per hectare than any terrestrial ecosystem
Is there an ecosystem that could have too many primary producers? If so how would it affect the environment?
-Can throw the ecosystem balance off resulting in the community crashing after a series of events -sometimes they can be toxic which will harm an ecosystem in one step.
There is huge variation from one biologist's estimate to the next. Why is it so hard to figure this out? After all, it's important that we know so that we can work to avoid a global catastrophe. The problem, it seems, goes back to the reasons behind the tremendous human success in the first place. We are so clever that we appear to keep increasing the carrying capacity before we ever bump into it. We do this in a variety of ways, all made possible by various technologies that we invent. In particular, we:
1) Expand into new habitats With fire, tools, shelter, and efficient food distribution, we can survive almost anywhere on earth. 2) Increase the agricultural productivity of the land With fertilizers and modern, mechanized agricultural methods, and selection for plants and animals with higher yields, fewer people can now produce much more food than was previously thought possible. 3) Circumvent the problems that usually accompany life at higher densities Public health and civil engineering advances make it possible for higher and higher densities of people to live together with minimal problems from waste and infectious diseases.
For any species, there is always a risk of extinction. This risk can be larger or smaller, depending on certain features. Here we look at three important aspects of species' biology that can influence their extinction risk:
1) Geographic range: 2) Local population size: 3) Habitat tolerance:
The archaea exhibit tremendous diversity and are often divided into five groups based on their physiological features: 1. Thermophiles ___ 2. Halophiles ____ 3. High- and low-pH-tolerant archaea 4. High-pressure-tolerant archaea, ___ 5. Methanogens, ___
1. ("heat lovers"), which live in very hot places 2. ("salt lovers"), which live in very salty places 4. found as deep as 4,000 meters (about 2.5 miles) below the ocean surface, where the pressure is almost 6,000 pounds per square inch (compared with an air pressure of less than 15 pounds per square inch at sea level) 5. which are anaerobic and produce methane
Viral Replication:
1. After the virus binds to the host cell's membrane, the viral DNA enters the cell. 2. Viral DNA is replicated into dozens of new copies, using the host's metabolic machinery and energy 3. Viral mRNA is transcribed from the viral DNA 4. New viral proteins are synthesized, again using the host's protein - production molecules 5. The new viral DNA and proteins assemble, forming many new virus particles
Overview:
1. Big herbivores eat acacia plants. 2. Restricting herbivores causes acacia plants to invest less in mutualistic ants. 3. Reduced support of the ants helps competing ants and stem-boring beetles to invade. 4. Formation of bore holes by the beetles slows plant growth and increases plant mortality.
three key distinctions into which we can group all of the animals.
1. Does the animal have specialized cells that form defined tissues? 2) All animals with defined tissues develop in a shape that has some sort of symmetry: radial or bilateral. 3) During gut development, does the mouth or anus form first?
Intervention has unintended consequences:
1. Reduced predation → reduced energy investment in defense against predators. 2. Reduced investment (sugary bribe for ants) → reduced number of acacia ants 3. Reduced number of acacia ants → opportunity for ant competitors to get in. 4. Increased number of competitor ants → increase in stem-boring beetles and plant damage.
The Frozen Ark: Zoological Society of London and Natural History Museum of the University of Nottingham
1: Scientists take whole insects, or small tissue samples from animals so life is not endangered 2: Tissue may then be frozen for safe-keeping 3: DNA extracted from tissue sample, either straight after it was obtained or after freezing 4: DNA can be used for research, which may one day lead to resurrection of extinct species 5: Some DNA samples are sent to other labs as an insurance against damage or loss 6: Unused DNA can be frozen, potentially for thousands of years The collection and preservation of species before they are lost forever is occurring with intention to either reintroduce the species or at least study the unique molecules they produce for medical use.
These two changes, on their own, should not have been bad for the enclosed plants. The following is what happened though:
3. Reduced number of acacia ants → opportunity for ant competitors to get in. 4. Increased number of competitor ants → increase in stem-boring beetles and plant damage.
If K = 100,000 r = 0.1 How many new individuals when; N = 1000 N = 50,000 N = 990,000
A.) (100,000-90,000)/100,000 = 0.1 B.) (100,000-50,000)/100,000 = 0.5 C.) (100,000-1000)/100,000 = 0.9
Neandertals, Homo neanderthalensis
About the same size as modern humans More robust and muscular Lived in organized groups Probably hunted large mammals Interbred with Homo sapiens -Eurasian H. sapiens have 3-4% H. neanderthalensis DNA -Sub-Saharan African H. sapiens ~1%
Take-home message 16.7 ecosystem disturbance
An ecosystem disturbance is almost reversible as long as the disturbance does not include the complete extinction of any species, so they can re-establish their populations. An ecosystem disturbance that involves the complete loss of a species to extinction is irreversible because a species, once lost, may never exist again. Each species is the result of a long and uninterrupted evolutionary history, involving an interplay of random and selective forces and producing a unique genome. Once lost, a species can never exist again (Figure 16-15). For this reason, ecosystem disturbances that involve the loss of species can have more devastating consequences than those that do not lead to extinctions, no matter how great the changes to the abiotic environment might be.
Some disturbances are almost reversible
An ecosystem disturbance is reversible when the disturbance alters the biotic (living organisms) and abiotic (decaying organisms, soil, rocks) nature of the habitat but does not result in the complete extinction of any species, making it possible for species to re-establish their populations. The example of the New England forests is based on a disturbance that was caused by humans—clearing land for agriculture in the 1700s—but wind storms, forest fires, floods, and volcanic eruptions have been clearing forests throughout the history of life. If an ecosystem disturbance involves the complete loss of a species to extinction, however, the disturbance is irreversible.
Take-home message 15.1 ecosystems
An ecosystem is a community of biological organisms plus the non-living components in the environment with which the organisms interact. Ecosystems are not just obvious places such as ponds, deserts, and tropical rainforests, but also digestive tracts of organisms and even a shell of a beetle.
Invasive species:
An organism that is able to proliferate and take over an ecosystem -Introduction of non-native species --No natural predators or diseases (pythons in FL) --Life histories that outcompete the life histories of species natural to the area (honeysuckle, OH) -Change in environment --Nutrient influx to waterways (toxic algae, Toledo)
Surface Glycoproteins:
Bind to receptors on the surface of the host cell and allow the virus to enter Allow the virus to break free from the host cell
Ice cap melting
Both environmental and biological evidence already reveal the effects of global warming. The Arctic Ocean ice cap is melting, and the glaciers that cover Antarctica and Greenland also have been melting at unprecedented rates—and those rates are increasing.
Populations with completely overlapping niches cannot coexist forever. Competition for resources occurs until;
Competitive exclusion: one species outcompetes the other and drives them to local extinction Resource partitioning:, through character displacement, or until one becomes extinct in that location. Character displacement: one or both species evolve in ways that reduce the competition
Anthropocene: The period of humans detailed
Data on current rates of extinction in every well-studied group of plants and animals support the hypothesis that a mass extinction is underway. Among the mammals, 11% of all species are currently endangered, under imminent threat of extinction, and 14% are threatened, characterized as vulnerable to extinction. Among birds, 4% of all species are endangered and 50% are in decline. Almost a third of all amphibian species are threatened. Among fish, mollusks, insects, fungi, and plants, the story is the same. Historically, background extinctions rates are about one extinction per million species per year. The numbers above suggest that current extinction rates are 1000 times (or more) greater than usual. It is difficult to know the exact magnitude of the problem because, as we saw in Chapter 10, biologists don't have much of an idea about how many species there are on earth—the estimates range from 5 million to 100 million. Unlike the last mass extinction event, in which the dinosaurs and most other species were wiped out in the wake of an asteroid hitting earth, the cause of this current mass extinction seems to be the result of the activity of one species—humans. Ironically, it is the unprecedented success of humans that is responsible for this situation. The resource needs of so many people have inevitably interfered with the ability of other species to coexist with us.
effects of acid rain precipitation
Dramatic evidence of the direct effects of acid precipitation on vegetation can be found in mountain forests that are often blanketed by fog. When trees are exposed to acid fog, year after year, their leaves are damaged, their rates of photosynthesis decrease, and, eventually, many of the trees die. The indirect effects of acid precipitation on forests are not as conspicuous as the direct effects, but they are more far-reaching. As acid falls on the soil, it carries away calcium, potassium, magnesium, and sodium ions. These ions are essential nutrients for plants, and when they are leached out of the soil, the rate of plant growth is reduced. Some forest animals also feel the impact of this change in soil chemistry—when calcium is depleted, the shells of snails are thinner than usual. As a result of the thinning of snail shells, birds that eat snails receive less calcium than normal, and these birds lay eggs with shells so fragile that they can crack while the parents are incubating them. Lakes and streams are also affected directly and indirectly by acid precipitation, and some lakes in the northeastern United State and in Northern Europe have pH values as low as 4.0 to 4.3—which is 1000 times more acidic than pure water.
the phosphorous cycle detailed
Every molecule of ATP and DNA requires phosphorus. Virtually no phosphorus is available in the atmosphere, though. Instead, soil serves as the chief reservoir. Like nitrogen, phosphorus is chemically converted—"fixed"—into a form usable by plants (phosphate) and then absorbed by their roots. It cycles through the food chain as herbivores consume plants and carnivores consume herbivores. As organisms die, their remains are broken down by bacteria and other organisms, returning the phosphorus to the soil. The pool of phosphorus in the soil is also influenced by the much slower process of rock formation on the sea floor, its uplifting into mountains, and the eventual weathering of the rock, releasing its phosphorus.
Eco-"systems"
Every system has defined parameters. You can go from very small to very large systems.
KNOWN Fertilizers, mainly P, from residential and agricultural sources caused a spike in microcystin producing cyanobacteria
Experiment Developed a method for rapidly screening waters for photosynthetic pigments associated with microcystin producing species
Niche: Where a species fits into the environment two types
Fundamental Niche: The extent of a species without competition, or external factors. Where it could grow. Realized Niche: Where a species is actually found as a result of competition and external factors. Where it does grow.
What is a fungus?
Fungi are decomposers of symbionts: Fungi are sessile: Fungi have cell walls made of chitin:
Landscape conservation:
Geared toward conserving not just species, but habitats and ecological processes
The Homo sapiens who migrated through the Indo-Australian Archipelago encountered two species of humans,
Homo erectus and Homo floresiensis.
How many people can earth support?
Humans are a phenomenally successful species. The numbers don't lie. There are more than 7 billion people alive today. And current birth rates exceed death rates by so much that we add 80 million more people to the total each year. But for all of our success, the laws of physics and chemistry still apply. We all need food to eat for energy, and we need space to live. We need a variety of other resources, too, and we also need the capability of processing and storing all of the waste products we generate. Because of these limits to perpetual population growth, we may in fact become victims of our own success. This we know for certain: human population growth cannot continue forever at the current rate. Like every other species, our environment has a carrying capacity beyond which the population cannot be maintained. The question is: How high can it go? What is our carrying capacity? This, unfortunately, is a difficult question to answer—although not for a lack of trying. For more than 300 years biologists have been making estimates, starting when Anton von Leeuwenhoek (the inventor of the microscope) made an estimate of just over 13 billion people. The median of all the old as well as the new estimates is just over 10 billion, and the United Nations conservatively suggests that it is somewhere between 7 and 11 billion. I've seen estimates up to 15 billion, but most top out around 12 billion.
What would happen if more than two eggs survived?
If the number were more than one offspring per individual, the population would grow and grow and grow until the earth was covered with cod and every other species. But that hasn't happened, and it can't.
house mouse
Other animals are a bit—but only a bit—more restrained in their reproduction. The house mouse reaches maturity in about one month and produces litters of six to ten offspring nearly every month, sometimes generating more than one hundred offspring in its first year of life.
3) Rate of disturbance.
Over time, the best competitor for a resource is expected to outcompete other species, excluding them from the community and thus reducing species richness. Communities may be kept from reaching this state, though—in a number of ways. Factors such as predation, or environmental perturbations such as fires, can prevent any one species from excluding others. For this reason, a habitat with an intermediate amount of disturbance is expected to have the greatest species richness.
Protein fragment (organic) v. inorganic fertilizer
Plants can't absorb the nitrogen in that protein fragment since it is so large. Therefore detrivores need to first eat/breakdown organic matter to release the nutrients in a small inorganic form
In recovery: Ozone Layer Depletion
Problem: increased levels of ultraviolet light reach the earths surface, leading to a greater incidence of health problems in animals and decreased rates of photosynthesis in plants Cause: synthetics chemicals known as chlorofluorocarbons (CFCs) leak into the atmosphere, where they cause the breakdown of ozone. Strategies for solution: reduced production and emission of CFCs When CFC molecules leak into the atmosphere, they rise to the stratosphere, where sunlight knocks a chlorine atom off the CFC molecule. These free chlorine atoms then catalyze the breakdown of ozone to oxygen.
Take-home message 15.15 acacia
Study of acacia-ant mutualisms and attempts to manipulate them reveals that community interactions are very complex. Within an ecosystem, seemingly helpful, straightforward manipulations may have significant negative consequences.
Take-home message 15.16 succession
Succession is the usually predictable change in the species composition of a community over time. In primary succession, the process begins in an area with no life and no soil. In secondary succession, the process occurs in an area where life is already present.
Picture a lush nature scene: some greenery, a bit of rotting wood, and abundant wildlife. Grazing animals abound, while predators feed on other animals and their eggs. Parasites are poised, looking for hosts, and, just below the surface, scavengers find meals among the organic detritus. But now, imagine that the entire scene gets up and walks away! The "camera" in your mind pulls back to reveal that the entire scene is playing out on the back of a beetle no more than two inches long.
The host of this mini-ecosystem is a beetle from New Guinea called the large weevil. The weevil is camouflaged from its predators by lichens—fungi and photosynthetic algae living together—while the lichens are given a safe surface on which to live. And the garden of lichens supports a wide range of other organisms, from tiny mites to a variety of other microscopic invertebrates, some free-living and some parasitic.
Density-dependent Factors
The limitations on a population's growth that are a consequence of population density This ceiling on growth is the carrying capacity, K, of the environment.
Density-dependent Factors detailed
The limitations on a population's growth that are a consequence of population density—the number of individuals within a given area—are called density-dependent factors, and they cause more than discomfort. With increased density, a population's growth is reduced as limited resources slow it down. This ceiling on growth is the carrying capacity, K, of the environment. And as a population size approaches the carrying capacity of the environment, death rate increases; migration rates increase (as individuals seek more hospitable places to live); and a reduction in birth rates usually occurs, too, as low food supplies give rise to poor nutrition which, in turn, reduces fertility.
fern forests
The major evolutionary advancement was vascular tissue (and therefore roots), which allowed the transport of water and nutrients throughout the body of the plant. This allowed for ferns to grow much taller, thereby utilizing a new niche and outcompeting smaller plants for light.
Energy flows from producers to consumers.
The sun is where our pathway of energy flow begins. Most of the energy is absorbed or reflected by the earth's atmosphere or surface, but about 1% of it is intercepted and converted to chemical energy through photosynthesis. That intercepted energy is then transformed again and again by living organisms, making about four stops as it passes through an ecosystem. Let's examine what happens at each stop, known as trophic levels.
Anthropocene:
The period of humans
Species Diversity:
The relative quantity of different species within the community. Communities that are more evenly distributed will have higher calculated diversity.
The archaea exhibit tremendous diversity and are often divided into five groups based on their physiological features
Thermophiles Halophiles High- and low-pH tolerant High-pressure tolerant Methanogens* (produce methane, powerful green house gas)
Three Phenomena May Trigger Adaptive Radiations
Three different phenomena tend to trigger adaptive radiations. After one of these phenomena occurs, surviving species find themselves in locations where they suddenly have access to plentiful new resources. Mass extinction events. Colonization events. Evolutionary innovations.
The "Life-Dinner Hypothesis"
What's more important, getting your dinner tonight or living tonight?
disruptive impacts: acid rain detailed
When fossil fuels are burned, the gases sulfur dioxide (SO2) and nitrogen dioxide (NO2) are produced. These gases react with water vapor in the atmosphere to produce sulfuric acid (H2SO4) and nitric acid (HNO3), and these acids fall to earth as acid precipitation.
basic carbon cycle of living systems
air(atmosphere) --> plants --> animals --> air air --> plants = CO2 (photosynthesis) plants --> animals = carbohydrates (eating) animals --> air = CO2 (respiration) Plants also go to CO2 (respiration)
Adaptive radiation occurs when
a small number of species diversify into a larger number of species. three phenomena tend to trigger adaptive radiation Mass extinction events. Colonization events. Evolutionary innovations.
Fungi most likely arose from
a unicellular, flagellated, aquatic protist more than 500 million years ago (and possibly as long as 1.3 billion years ago). Close to 100,000 species have been described, but the total number of species is estimated to be about 1.5 million.
Most industrialized countries
are growing slowly or not at all; most of the population is middle-aged or old. In these countries, such as Norway, the age pyramid is more rectangular than pyramid-shaped. Because birth rates are low, the bottom of the pyramid is not very wide. And because death rates are low, too, the higher age classes in the pyramid don't get significantly narrower. Instead, the cohorts remain about the same size all the way into the late sixties and seventies, at which point high mortality rates finally cause them to narrow. This gives the pyramid a more or less rectangular shape.
the three domains of life
bacteria archaea eukarya
Exponential growth occurs when
each individual produces more thant he single offspring necessary to replace itself. Accoridng to realistic (and moderate) estimates of brith and death rates, a population of just 500 elk would grow to mare than abillion individuals within 80 years and eventually would cover the earth.
ecology
ecology is the study of interactions between organisms and their environments. it can be studied at many different levels including: individuals populations communities ecosystems
As conservation plans aimed at preserving habitats increase,
efforts focusing on individual species still continue to be effective. Several strategies targeting individual species for conservation have been particularly successful at preserving large amounts of biodiversity beyond that single species.
enveloped virus
enveloped viruses wrap themselves in a bit of the plasma membrane of the host cell as they are released
gradual change
evolution by creeps: the pace of evolution occurs gradually in incremental steps
The values of biodiversity
extrinsic (utilitarian) value the value of biodiversity to humans, often described as ecosystem services, can be grouped in four categories of services: provisioning services cultural services regulating services habitat services These all benefit human quality of life
Members of the angiosperms include:
flowering trees, bushes, herbs, and grasses
Viruses have cracked the
glycoprotein code, and when they find a cell with the appropriate glycoprotein on its surface, they bind to that cell's plasma membrane and insert their genetic material into the cell. Inside the host cell, the viral DNA or RNA takes over the cellular machinery and uses it to produce more viruses. Viruses carry out nearly all of their activities by hijacking materials and organelles in the host cell. Viral proteins are synthesized in exactly the same way as host cell proteins—mRNA binds to ribosomes and tRNA matches the correct amino acid to each mRNA codon. The mRNA comes from the virus, but the protein-building machinery all comes from the host cell, as does the ATP required to synthesize the new viral protein.
populations
groups of individual organisms that interbreed with each other
Colonization events.
moving to a new location with new resources (and possibly fewer competitors) colonizers can rapidly diversify
A species evolutionary history is shaped by
natural selection due to the symbiotic interactions they encounter -Not just regulated to predator/prey (parasitism) relationships -Both species are affected by natural selection, except for commensalism relationships.
If the past is a guide to the future, we know this:
no species lasts forever. Speciation is always producing new species, but extinction, the complete loss of all individuals in a species population, takes them away. Extinction, which is always occurring, is a risk faced by all species.
non-enveloped virus
non-enveloped viruses are enclosed only by a capsid
At the moment consensus agrees bacteria are
not living
Most ecosystems that are inverted are limited by
nutrients (N, P)
Plants receive ____ and fungus receive ___
nutrients (N,P,K) glucose
The physical/abiotic environment,
often referred to as the organisms' habitat, consists of: -the chemical resources of the soil, water, and air, such as carbon, nitrogen, and phosphorus, and -the physical conditions, such as the temperature
commensalism
one species benefit while the other has no effect
Energy flows from
one stop to the next in a food chain, but not in the way that runners pass a baton in a relay race. The difference is that, at every step in the food chain, much of the usable energy is lost as heat. An animal that eats five pounds of plant material doesn't convert that into five new pounds of body weight. Not by a long shot. In the next section, we'll see how this inefficiency of energy transfers ensures that most food chains are very short.
In particular, as population size increases,
organisms experience all of these factors to some degree reduced food supplies due to competition diminished accessibility to places to live and breed due to competition increased incidence of parasites and disease which can spread more easily when their hosts live at higher density increased predation risk as predator populations grow in response to the increased availability of their prey and also as the more densely packed prey become more visible.
Beyond habitat loss, other factors reducing biodiversity include
overexploitation of species, including those killed for food, furs, and medicinal products. Bonobos (Pan paniscus), for example, a type of chimpanzee and our closest living relative, are no longer seen in the wild because they have been driven to extinction, hunted for food. And, as we'll see later in this chapter, the introduction of exotic species, too, is having a significantly adverse effect on biodiversity.
Trickery:
this orchid flower deceives the male bee into carrying its pollen. When the bee attempts to mate with the flower it picks up pollen which it delivers to other orchids.
Analyses of genetic sequences indicate that the archaeans and the bacteria diverged about Although it is likely that some genetic exchanges continued to occur between them, Approximately 2.5 billion years ago the eukarya
three billion years ago. they have evolved in largely independent paths ever since. split off from the archaea
Angiosperms have developed a way to
transfer pollen efficiently from the anthers of one flower to the stigma of another: get an animal to carry it!
• Corridors
—even just relatively narrow strips of land—that connect larger natural preserves, allow gene flow, and reduce inbreeding among distinct populations in the different preserves
succession of communities
• The first arrivals—called colonizers or pioneer species—in a lifeless, soil-less area are usually bacteria or fungi or other photosynthetic microorganisms, floating in on the air. • Lichens—symbiotic associations between a fungus and a photosynthetic alga or bacterium—are also common first colonizers. They can grow on rocks and can generate energy through photosynthesis. As they grow, lichens change their environment, secreting acids that break down the rocks and release useful minerals, making the terrain more hospitable for other organisms. • Mosses also tend to arrive in the early stages, using many of the nutrients freed up by lichens. They trap moisture and can provide a hospitable site for germination of the seeds of other plants. • Following mosses, small herbs often arrive. Later, some shrubs may begin to thrive, shading out the mosses and herbs. • Shrubs, in turn, are eventually outcompeted and shaded out by small trees. • And the first trees generally are outcompeted by taller, faster-growing trees.
Highlights
•Global ecosystem services estimated between $US 125 - 141 trillion/yr. •Global loss of ecosystem services due to land use change is $US 4.3-20.2 trillion/yr. *•Eco-services contribute more than twice as much to human well-being as global GDP. •Estimates in monetary units are useful to show the relative magnitude of eco-services.* •Valuation of ecosystem services is not the same as commodification or privatization. •Ecosystem services are best considered public goods requiring new institutions.
