chap 40, 41, 42, 43 for part 2 final exam

from book pg. 886: Bottom-Up and Top-Down Controls

The ways in which adjacent trophic levels affect one another can be useful for describing community organization. Let's consider the three possible relationships between plants (V for vegetation) and herbivores (H): V→HV←HV↔H The arrows indicate that a change in the biomass of one trophic level causes a change in the other trophic level. V→H means that an increase in vegetation will increase the numbers or biomass of herbivores, but not vice versa. In this situation, herbivores are limited by vegetation, but vegetation is not limited by herbivory. In contrast, V←H means that an increase in herbivore biomass will decrease the abundance of vegetation, but not vice versa. A double-headed arrow indicates that each trophic level is affected by changes in the biomass of the other. Two models of community organization are common: the bottom-up model and the top-down model. The V→H linkage suggests a bottom-up model, which postulates a unidirectional influence from lower to higher trophic levels. In this case, the presence or absence of mineral nutrients (N) controls plant (V) numbers, which control herbivore (H) numbers, which in turn control predator (P) numbers. The simplified bottom-up model is thus N→V→H→P. To change the community structure of a bottom-up community, you need to alter biomass at the lower trophic levels, allowing those changes to propagate up through the food web. If you add mineral nutrients to stimulate plant growth, then the higher trophic levels should also increase in biomass. If you change predator abundance, however, the effect should not extend down to the lower trophic levels. In contrast, the top-down model postulates the opposite: Predation mainly controls community organization because predators limit herbivores, herbivores limit plants, and plants limit nutrient levels through nutrient uptake. The simplified top-down model, N←V←H←P, is also called the trophic cascade model. In a lake community with four trophic levels, the model predicts that removing the top carnivores will increase the abundance of primary carnivores, in turn decreasing the number of herbivores, increasing phytoplankton abundance, and decreasing concentrations of mineral nutrients. The effects thus move down the trophic structure as alternating +/−effects. Ecologists have applied the top-down model to improve water quality in lakes with high abundances of algae. This approach, called biomanipulation, attempts to prevent algal blooms by altering the density of higher-level consumers. In lakes with three trophic levels, removing fish should improve water quality by increasing zooplankton density, thereby decreasing algal populations (Figure 41.18). In lakes with four trophic levels, adding top predators should have the same effect. from book but discussed in lecture: Ecologists in Finland used biomanipulation to help purify Lake Vesijärvi, a large lake that was polluted with city sewage and industrial wastewater until 1976. After pollution controls reduced these inputs, the water quality of the lake began to improve. By 1986, however, massive blooms of cyanobacteria started to occur in the lake. These blooms coincided with an increase in the population of roach, a fish species that eats zooplankton, which otherwise keep the cyanobacteria and algae in check. To reverse these changes, ecologists removed nearly 1,000,000 kg of fish from the lake between 1989 and 1993, reducing roach abundance by about 80%. At the same time, they added a fourth trophic level by stocking the lake with pike perch, a predatory fish that eats roach. The water became clear, and the last cyanobacterial bloom was in 1989. Ecologists continue to monitor the lake for evidence of cyanobacterial blooms and low oxygen availability, but the lake has remained clear, even though roach removal ended in 1993. pic description: Decreasing the abundance of fish that ate zooplankton results in a decrease in the biomass of algae, improving water quality. Arrow thickness indicates the relative strength of each top-down control.

Global Warming Mechanism

(don't need to memorize, just undnerstand that fossil fuels cause global warming? lol)

community ecology (definition from quizlet)

The study of how interactions between species affect community structure and organization

Geological Time Scale of Temperatures and CO2 Levels

just read pic i guess?

Global Warming

we are trying to cap the annual rise in temperature to 1.5 degrees celsius

why does winter and summer happen

we aren't any closer to the sun during summer, the angle in which the sun rays come into earth affect the heat we feel

Population Growth Predicted by the Exponential Model

• A population growing exponentially increases at a constant rate (r) • This results in a J-shaped growth curve • A population with a higher intrinsic rate of increase will have a steeper growth curve (from dr. sata: slower j-shape, takes much longer generation to reach the same population size) pic description: This graph compares growth in a population with r = 1.0 (blue curve) to growth in a population with r = 0.5 (red curve).

Gross and Net Primary Productivity

• Total primary production is known as the ecosystem's gross primary production (GPP) • GPP is measured as the conversion of solar energy into chemical energy through photosynthesis per unit time • Net primary production (NPP) is GPP minus energy used by primary producers for respiration (autotrophic respiration) NPP = GPP - Ra • Only NPP is available for the next trophic level • Units can be in energy or mass - e.g. [kcal/ m^2yr] or [g C /m^2yr]

Effects of Caring for Offspring on Parental Survival in Kestrels

• Selective pressures influence the trade-off between the number and size of offspring • Plants and animals whose young are likely to die often produce large numbers of small offspring • For example, plants that colonize disturbed environments produce many small seeds from book pg. 871: EVOLUTION Natural selection favors traits that improve an organism's chances of survival and reproductive success. The traits that affect an organism's schedule of reproduction and survival make up its life history. Examples of such life history traits include when reproduction begins, how often the organism reproduces, and the number and size of offspring produced per reproductive episode. "Trade-offs" and Life Histories No organism could produce thousands of offspring and provision each of them as well as do horses and other large mammals that give birth to one or a few offspring. There is a trade-off between the number of offspring and the amount of resources a parent can devote to each offspring. Such trade-offs occur because organisms do not have access to unlimited amounts of resources. As a result, the use of resources for one function (such as reproduction) can reduce the resources available for supporting another function (such as survival). In kestrels, for example, caring for a larger number of young lowered the survival rates of the parents (Figure 40.22). In another study, researchers in Scotland found that female red deer that reproduced in a given summer were more likely to die the next winter than were females that did not reproduce. Selective pressures also influence trade-offs between the number and size of offspring. Plants and animals whose young have a low chance of survival often produce many small offspring. For example, plants that colonize disturbed environments usually produce many small seeds, only a few of which may reach a suitable habitat. Small size may also increase the chance of seedling establishment by enabling the seeds to be carried longer distances to a broader range of habitats (Figure 40.23a). Animals that suffer high predation rates, such as quail, sardines, and mice, also tend to produce many offspring. pic description: Researchers transferred chicks among nests to produce reduced broods (three or four chicks), normal broods (five or six), and enlarged broods (seven or eight). They then measured the percentage of male and female parent birds that survived the following winter.

Water Usage in the USA (he said for the graphs only learn how to interpret and apply them)

• 80% water consumed for agriculture • Some states use up to 90% water for agriculture

Energy Flow in Marine Ecosystem (Eddy et al, 2021) (not in the book, on slides only)

(A) A trophic pyramid depicts the classic view of production flowing from primary producers to secondary consumers. Roman numerals indicate trophic level. A 10% transfer efficiency of production is indicated by lighter grey in the pyramid, highlighting how little primary production gets transferred to the top of the food web. (B) At the individual scale, metabolic processes determine growth efficiency. (C) At the species population scale, maturation, reproduction, and survival of individual life cycles influence transfer efficiency. (D) At the ecosystem scale, complex energy pathways, including the microbial loop [depicted middle left, which includes dissolved organic carbon (DOC)] and differing paths through benthic and pelagic communities influence transfer efficiency.

Mutualism Between Acacia Trees and Ants

(a) Certain species of acacia trees (genus Acacia) in Central and South America have hollow thorns (not shown) that are home to stinging ants of the genus Pseudomyrmex. The ants feed on nectar produced by the tree and on protein-rich swellings (yellow in the photograph) at the tips of leaflets. (b) The acacia benefits because the pugnacious ants, which attack anything that touches the tree, remove fungal spores, small herbivores, and debris. They also clip vegetation that grows close to the acacia. (from evelyn - the acacia trees secrete a nectar ants love and have thorns that ants can burrow in to stay safe so the ants are protective of the trees. ants will get rid of any fungal or bacterial pathogen as well as attack any other animal that tries to colonize the tree)

Accelerated Human Disease Spread (don't need to memrize, just understand and see pic)

(don't need to memrize, just understand and see pic)

Distribution of Major Terrestrial Biomes 1) define biome 2) ____ types of biomes are?

1) A biome is a large community of vegetation and wildlife adapted to a specific climate. 2) The five major types of biomes are aquatic, grassland, forest, desert, and tundra. aquatic biomes - where most oceans are grasslands - forests and tundra savannas - more in subtropical region deserts - right above and below the equator

1) interspecific interactions - define 2) 3 ways they're grouped ^^ 3) _____ examples are _____

1) Ecologists call relationships between species in a community interspecific interactions (can remember by thinking interstate means between multiple states as interspecific means between multiple species) 2) Interspecific interactions are grouped according to whether they have positive (+), negative (−), or no effect (0) on the survival and reproduction of the interacting individuals of each species 3) 6 examples are (descriptions are from the book): 1. competition (-/-) - interaction that occurs when individuals of different species compete for a resource that limits the survival and reproduction of both individuals. 2. predation (+/-) - a positive effect on the survival and reproduction of members of the predator population and a negative effect on members of the prey population 3. herbivory - (+/-) exploitative interaction in which an organism—an herbivore—eats parts of a plant or alga, thereby harming it but usually not killing it. While large mammalian herbivores such as cattle, sheep, and water buffalo may be most familiar, most herbivores are actually invertebrates, such as grasshoppers, caterpillars, and beetles. In the ocean, herbivores include sea urchins, some tropical fishes, and certain mammals, including the manatee 4. parasitism - (+/-) exploitative interaction in which one organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the process. Parasites that live within the body of their host, such as tapeworms, are called endoparasites; parasites that feed on the external surface of a host, such as ticks and lice, are called ectoparasites 5. mutualism - (+/+) The survival and reproduction of individuals of each species increase in the presence of the other species. 6. commensalism - (+/0) An interaction that benefits the individuals of one species but neither harms nor helps the individuals of the other species Like mutualism, commensalisms are common in nature. For instance, many wildflowers that grow best in low light levels are found only in shaded, forest floor environments. Such shade-tolerant "specialists" depend entirely on the trees that tower above them—the trees provide their dim habitat. Yet the survival and reproduction of the trees are not affected by these wildflowers. Thus, these species are involved in a +/0 interaction in which the wildflowers benefit and the trees are not affected.

Three Levels of Biodiversity

1) Genetic diversity comprises genetic variation within a population and between populations. Population extinctions reduce genetic diversity, which in turn reduces the adaptive potential of the entire species 2) Species diversity is the number of species in an ecosystem or across the biosphere • An endangered species is in danger of becoming extinct throughout all or much of its range • A threatened species is likely to become endangered in the near future 3) Community and ecosystem diversity, the variety of ecosystems in the biosphere • For example, more than 50% of wetlands in the contiguous United States have been drained and converted to agricultural or other use

Biotic Factors 1) define 2) ______ types of biotic factors + describe each 3) example (pic description)

1) Interactions with other species can limit species distributions 2) Such biotic factors can include • Predation (carnivores) • Herbivory • Mutualism (helping each other) • Parasitism (one organism survives as a parasite on another organism) • Competition 3) pic description: Seaweed abundance in areas from which the long-spined sea urchin (Centrostephanus rodgersii ) had been removed was much higher than seaweed abundance in adjacent control sites from which the urchin was not removed. (aka urchins kept the amount of seaweed in control)

Circulation of Surface Water in the Oceans Around North America (see pic) 1) Ocean ______ influence what by doing what? 2) Example 3) Another example

1) Ocean currents influence coastal climates by heating or cooling overlying air masses that pass across the land 2) The California Current carries cold water southward along western North America 3) The Gulf Stream carries warm water from the equator to the North Atlantic pic description: The California Current carries cold water southward along the western coast of North America. Along the eastern coast, the Labrador Current carries cold water southward, and the Gulf Stream moves warm water toward northern Europe.

Scope of Ecological Research 1) Organismal ecology 2) Population ecology 3) Community ecology 4) Ecosystem ecology 5) Landscape ecology

1) Organismal ecology considers how an organism's structure, physiology, and behavior meet environmental challenges 2) Population ecology considers factors affecting population size over time 3) Community ecology considers how interactions between species affect community structure and organization (Dr. sata's def - how various populationns together will interact and affect each other) 4) Ecosystem ecology emphasizes energy flow and chemical cycling between organisms and the environment (Dr. sata's def - several communinties and the environnment) 5) Landscape ecology focuses on the factors controlling exchanges of energy, materials, and organisms across multiple ecosystems (Dr. sata's def - including the surroundings ex. energy, materials)

Seasonal Variation in Sunlight Intensity 1) Seasonal variations of (2) ______ with _____ _____ 2) This seasonality is caused by (2) 3) what causes wet and dry seasons 4) upwelliing - what causes it + define 5) what upwelling causes 6) equinoxes and soltices - read all + see pic

1) Seasonal variations of light and temperature increase with increasing latitude 2) This seasonality is caused by the tilt of Earth's axis of rotation and its annual passage around the sun 3) Belts of wet and dry air straddling the equator shift with the changing angle of the sun causing wet and dry seasons at 20° north and south latitude 4) Changing wind patterns alter ocean currents, causing upwelling, the movement of cold, nutrient-rich water from the ocean floor to the surface 5) This process stimulates phytoplankton growth supporting productive aquatic ecosystems 6) March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. December solstice: Northern Hemisphere tilts away from sun and has shortest day and longest night; Southern Hemisphere tilts toward sun and has longest day and shortest night. September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. June solstice: Northern Hemisphere tilts toward sun and has longest day and shortest night; Southern Hemisphere tilts away from sun and has shortest day and longest night.

Abiotic Factors 1) define 2) ______ types of biotic factors + describe each 3) example (pic description)

1) Species are not found in areas where physical conditions prevent their survival or reproduction 2) Abiotic factors limiting species distributions include (6): • Temperature • Water - availability of water • Oxygen - availability of oxygen • Salinity • Sunlight • Rocks and soil 3) pic description: Since the 1950s, water temperatures along the coast of Tasmania have increased, allowing the sea urchin C. rodgersii to expand its range to the south. The orange type indicates the years when C. rodgersii was first observed colonizing those locations. Once its population has been established in a new location, C. rodgersii has eliminated the local kelp community.

Global Ecology 1) climate 2) _____ major physical components of climate are _____; _____ includes (3) 3) abiotic factors - define 4) biotic factors - define 5) Global climate patterns are determined largely by 6) The warming effect of the sun causes _____, which ______. This causes _____

1) The long-term prevailing weather conditions in an area constitute its climate 2) Four major physical components of climate are temperature, precipitation, sunlight, and wind precipitation includes rain, snow, dew, etc. 3) Abiotic factors are the nonliving chemical and physical attributes of the environment 4) Biotic factors are the other organisms that make up the living component of the environment 5) Global climate patterns are determined largely by solar energy and the planet's movement in space (from sata- determined by the way the Earth's angle is set up and how sunlight is impacting. the earth is also going around the sun, this is essential) 6) The warming effect of the sun causes temperature variations, which drive evaporation and the circulation of air and water. This causes latitudinal variations in climate

Global Climate Patterns pt. 2 1) Variation in the ______ of Earth's ______ at different _____ results in _____ 2) _____ winds blow how in the tropics? 3) _____ winds blow how in temperate zones? 4) Speed of earth's rotation is faster where and why?

1) Variation in the speed of Earth's rotation at different latitudes results in the major wind patterns 2) Trade winds blow east to west in the tropics 3) Westerlies (westerly flow) blow west to east in temperate zones 4) Speed of earth's rotation is faster at the equator bc the equator has a wider diameter so its spinning much faster than at the top of the earth • Speed at the equator 1,037 mph (1,670 km/h) • Speed at 45º lattitude is 733 mph (1,180 km/h)

Exploring Aquatic Biomes

1) Wetlands and Estuaries 2) Lakes 3) Streams and Rivers 4) Intertidal Zones: temperate (are rocky) and tropical 5) Coral Reefs (some of most diverse habitats on earth) - Symbiosis between corals and single-celled algal symbionts is the foundation for this entire biome 6) Oceanic Pelagic Zone - open ocean waters; where you get large migratory sways of fish; has primary producers like phytoplankton which form basis fo food web in the open ocean 7) Marine Benthic Zone - aka hydrothermal vents; ecosystem that evolved completely independently of the sun; made up of organisms whose lineages have never seen the sun

Effect of Global Warming on Animals and Animal Husbandry

• Spread of tropical animals to colder climate • Increased mortality due to heat waves • Reduced meat and milk production • Animals becoming extinct

Effect of Light, Temperature and CO2 on Photosynthesis (not in the book this is all from dr. sata)

1) light has an affect on photosynthesis relative photosynthesis increases with carbon dioxide concentration. this means that global warming and CO2 emissions actually aren't horrible for some plants lol, especially C3 plants; more light = more CO2 (see first graph) this is the best productivity 2) also temperature has an affect on photosynthesis there is always an optimal temperature ( i think higher temp = more CO2; see 2nd pic) c3 plants - some plants have evolved a c3 pathway where they aren't efficient in saving water they close the stomach, the photorespiration happens and they don't fix CO2 so they aren't very efficient. c4 plants - however with c4 plants, even when their stomachs close they use a diff enzyme to fix carbon dioxide and use it for the calvin cycle to make sugars; c4 plants do it in mesophyll cell and bundle sheath cell cam plants - do it in nighttime and daytime

Carbon Cycle

1. Biological importance Carbon forms the framework of the organic molecules essential to all organisms. from slides: Carbon-based organic molecules are essential to all organisms 2. Forms available to life Photosynthetic organisms utilize CO2 during photosynthesis and convert the carbon to organic forms that are used by consumers, including animals, fungi, and heterotrophic protists and prokaryotes. from slides: Photosynthetic organisms convert CO2 to organic molecules, those are used in turn by heterotrophs 3. Reservoirs The major reservoirs of carbon include fossil fuels, soils, the sediments of aquatic ecosystems, the oceans (dissolved carbon compounds), plant and animal biomass, and the atmosphere (CO2). The largest reservoir is sedimentary rocks such as limestone; however, carbon remains in this pool for long periods of time. All organisms are capable of returning carbon directly to their environment in its original form (CO2) through respiration. from slides: Carbon reservoirs include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, the atmosphere, and sedimentary rocks 4. Key processes Photosynthesis by plants and phytoplankton removes substantial amounts of atmospheric CO2 each year. This quantity is approximately equal to the CO2 added to the atmosphere through cellular respiration by producers and consumers. The burning of fossil fuels and wood is adding significant amounts of additional CO2 to the atmosphere. Over geologic time, volcanoes are also a substantial source of CO2 from slides: CO2 is taken up and released through photosynthesis and respiration; additionally, volcanoes, land use/lifestyle changes and the burning of fossil fuels contribute CO2 to the atmosphere

Nitrogen Cycle

1. Biological importance Nitrogen is part of amino acids, proteins, and nucleic acids and is often a limiting plant nutrient. from slides: Nitrogen is a component of amino acids, proteins, and nucleic acids 2. Forms available to life Plants can assimilate (use) two inorganic forms of nitrogen—ammonium (NH4+) and nitrate (NO3−)—and some organic forms, such as amino acids. Various bacteria can use all of these forms as well as nitrite (NO2−). Animals can use only organic forms of nitrogen. from slides: The main reservoir of nitrogen is the atmosphere (N2), though this nitrogen must be converted to NH4 + or NO3 - for uptake by plants, via nitrogen fixation by bacteria 3. Reservoirs The main reservoir of nitrogen is the atmosphere, which is 80% free nitrogen gas (N2). The other reservoirs of inorganic and organic nitrogen compounds are soils and the sediments of lakes, rivers, and oceans; surface water and groundwater; and the biomass of living organisms. from slides: Organic nitrogen is decomposed to NH4 + by ammonification, and NH4 + is decomposed to NO3 - by nitrification 4. Key processes The major pathway for nitrogen to enter an ecosystem is via nitrogen fixation, the conversion of N2 to forms that can be used to synthesize organic nitrogen compounds. Certain bacteria, as well as lightning and volcanic activity, fix nitrogen naturally. Nitrogen inputs from human activities now outpace natural inputs on land. Two major contributors are industrially produced fertilizers and legume crops that fix nitrogen via bacteria in their root nodules. Other bacteria in soil convert nitrogen to different forms. Examples include nitrifying bacteria, which convert ammonium to nitrate, and denitrifying bacteria, which convert nitrate to nitrogen gas. Human activities also release large quantities of reactive nitrogen gases, such as nitrogen oxides, to the atmosphere. from slides: Denitrification converts NO3 - back to N2

Necessity and Urgency for Sustainability

1. Current practices of resource utilization is complex and they are not sustainable if not properly managed 2. Lack of sustainability leads to resource depletion and human suffering in many ways 3. The impact of unsustainable practices in more severe on developing countries more than developed countries 4. It affects the socioeconomically disadvantaged people more that affluent society in all countries 5. Increase in human population and the demand on multiple resources place a major stress on sustainability 6. Fortunately, there are technical solutions readily available or that can be developed to mitigate and manage the risks in sustainability 7. Sustainable practices affect both intragenerational equity and intergenerational equity

Biological Hierarchy

1. organelle - nucleus is an example 2. cells - ex. human blood cells 3. tissues - ex. human skin tissue 4. organs and organ systems - (tissues form organs) organs, such as the stomach and intestine, make up the human digestive system (organs form organ systems) 5. organisms, populations, communities - In a forest, each pine tree is an organism. Together all the pine trees make up a population. All the plant and animal species in the forest comprise a community A population is a group of individuals of the same species living in an area. 6. ecosystem - ecosystems include living organisms and the environment in which they live 7. biosphere - encompasses all ecosystems on earth

Hydroponics

2 definitions from quizlet: 1. the process of growing plants in sand, gravel, or liquid, with added nutrients but without soil. 2. a technique of growing plants (without soil) in water containing dissolved nutrients from dr. sata: you can use hydroponics to grow some vegetables but you can't grow trees, rice, wheat, corn in this way so hydroponics application is limited; this is much more efficient than water usage

from book pg. 885 example from lecture: An Antarctic Marine Food Web

A food chain is not an isolated unit, separate from other feeding relationships in a community. Instead, a group of food chains are linked together to form a food web. Ecologists diagram the trophic relationships of a community using arrows that link species according to who eats whom. In an Antarctic pelagic community, for example, the primary producers are phytoplankton, which serve as food for the dominant grazing zooplankton, especially krill and copepods, both of which are crustaceans (Figure 41.15). These zooplankton species are in turn eaten by various carnivores, including other plankton, penguins, seals, fishes, and baleen whales. Squids, which are carnivores that feed on fishes and zooplankton, are another important link in these food webs, as they are in turn eaten by seals and toothed whales. pic description: Arrows follow the transfer of food from the producers (phytoplankton) up through the trophic levels. For simplicity, this diagram omits decomposers. At various times over the last two centuries, humans have also played a role in the Antarctic food web as consumers of fishes, krill, and whales.

Biological and Geochemical Processes Cycle Nutrients and Water in Ecosystems

Although most ecosystems receive abundant solar energy, chemical elements are available only in limited amounts. Life therefore depends on the recycling of essential chemical elements. • Gaseous carbon, oxygen, sulfur, and nitrogen cycle globally • Less mobile elements - phosphorus, potassium, and calcium - cycle locally • In studying cycling of water, carbon and nitrogen, ecologists focus on four questions: 1. Each chemical's biological importance 2. Forms in which each chemical is available or used by organisms 3. Major reservoirs for each chemical 4. Key processes driving movement of each chemical through its cycle

Sources and Movements of Drugs in the Environment

Among the pharmaceuticals that ecologists are studying are the sex steroids, including forms of estrogen used for birth control. Some fish species are so sensitive to certain estrogens that concentrations of a few parts per trillion in their water can alter sexual differentiation and shift the female-to-male sex ratio toward females. Researchers in Ontario, Canada, conducted a seven-year experiment in which they applied the synthetic estrogen used in contraceptives to a lake in very low concentrations (5−6 ng/L). They found that chronic exposure of the fathead minnow (Pimephales promelas) to the estrogen led to feminization of males and a near extinction of the population of this species from the lake. Many toxins cannot be degraded by microorganisms and persist in the environment for years or even decades. In other cases, chemicals released into the environment may be relatively harmless but are converted to more toxic products by reaction with other substances, by exposure to light, or by the metabolism of microorganisms. Mercury, a by-product of plastic production and coal-fired power generation, has been routinely expelled into rivers and the sea in an insoluble form. Bacteria in the bottom mud convert the waste to methylmercury (CH3Hg+), an extremely toxic water-soluble compound that accumulates in the tissues of organisms, including humans who consume fish from the contaminated waters.

2nd example of Defensive Adaptations in Animals: aposematic coloration

Animals with effective chemical defenses often exhibit bright aposematic coloration, or warning coloration, such as that of poison dart frogs (Figure 41.6b). Such coloration seems to be adaptive because predators often avoid brightly colored prey. (from Evelyn - poison dart frogs eat insects that have toxins and they're able to sequester the toxins from their diet and secrete it on their skin to defend themselves, also monarch butterflies sequester toxin from their diet. as caterpillars they eat milkweed which has toxins in it which are poisonous to predators so when they turn into butterflies they have a way to ward off predators by making them sick which is how they can afford to have such bright coloration)

CO2 Concentration over 400,000 Years (what has happened to carbon dioxide concentration overtime?)

CO2 concentration has been going up, see pic!!

Ecological Succession (from book pg/ 889) example from lecture: Glacial Retreat and Primary Succession at Glacier Bay, Alaska

Changes in the composition and structure of terrestrial communities are most apparent after a severe disturbance, such as a volcanic eruption or a glacier, strips away all the existing vegetation. The disturbed area may be colonized by a variety of species, which are gradually replaced by other species, which are in turn replaced by still other species—a process called ecological succession. When this process begins in a virtually lifeless area, such as on a new volcanic island or on the rubble (moraine) left by a retreating glacier, it is called primary succession. Another type of succession, secondary succession, involves the recolonization of an area after a major disturbance has removed most but not all of the organisms in a community, as in Yellowstone following the 1988 fires. During primary succession, the only life-forms initially present are often prokaryotes and protists. Lichens and mosses, which grow from windblown spores, are commonly the first macroscopic photosynthesizers to colonize such areas. Soil develops gradually as rocks weather and organic matter accumulates from the decomposed remains of the early colonizers. Once soil is present, the lichens and mosses are usually overgrown by grasses, shrubs, and trees that sprout from seeds blown in from nearby areas or carried in by animals. Eventually, an area is colonized by plants that become the community's dominant form of vegetation. Producing such a community through primary succession may take hundreds or thousands of years. Early-arriving species and later-arriving ones may be linked by one of three key processes. The early arrivals may facilitate the appearance of the later species by making the environment more favorable—for example, by increasing the fertility of the soil. Alternatively, the early species may inhibit establishment of the later species, so that successful colonization by later species occurs in spite of, rather than because of, the activities of the early species. Finally, the early species may be completely independent of the later species, which tolerate conditions created early in succession but are neither helped nor hindered by early species. discussed in class but this is from the book: Ecologists have conducted some of the most extensive research on primary succession at Glacier Bay in southeastern Alaska, where glaciers have retreated more than 100 km since 1760 (Figure 41.21). By studying the communities at different distances from the mouth of the bay, ecologists can examine different stages in succession. 1 The exposed glacial moraine is colonized first by pioneering species that include liverworts, mosses, fireweed, scattered Dryas (a mat-forming shrub), and willows. 2 After about three decades, Dryas dominates the plant community. 3 A few decades later, area is invaded by alder, which forms dense thickets up to 9 m tall. 4 In the next two centuries, these alder stands are overgrown first by Sitka spruce and later by western hemlock and mountain hemlock. In areas of poor drainage, the forest floor of this spruce-hemlock forest is invaded by sphagnum moss, which holds water and acidifies the soil, eventually killing the trees. Thus, by about 300 years after glacial retreat, the vegetation consists of sphagnum bogs on the poorly drained flat areas and spruce-hemlock forest on the well-drained slopes. pic description: The different shades of blue on the map show retreat of the glacier since 1760, based on historical descriptions.

Character Displacement: Indirect Evidence of past Competition

Closely related species whose populations are sometimes allopatric (geographically separate; see Concept 22.2) and sometimes sympatric (geographically overlapping) provide additional evidence for the importance of competition in structuring communities. In some cases, the allopatric populations of such species are morphologically similar and use similar resources. By contrast, sympatric populations, which would potentially compete for resources, show differences in body structures and in the resources they use. This tendency for characteristics to diverge more in sympatric than in allopatric populations of two species is called character displacement. An example of character displacement in Galápagos finches is shown in Figure 41.5. from Evelyn - finches that live on different islands have similar/comparable beak sizes [look at first 2 graphs in pic] (remember the beak depth/thickness of the finch determines what kind of nuts they can crack) vs. in sympatric populations of finches which are finches that live together on the same island, you can see that the trait of the beak thickness has diverged [look at last graph in pic] this is bc its much more effective to go after slightly different things than compete for the same thing. pic description: Allopatric populations of Geospiza fuliginosa and Geospiza fortis on Los Hermanos and Daphne Islands have similar beak morphologies (top two graphs) and presumably eat similarly sized seeds. However, where the two species are sympatric on Floreana and San Cristóbal, G. fuliginosa has a shallower, smaller beak and G. fortis a deeper, larger one (bottom graph), adaptations that favor eating different-sized seeds.

As population density increases, density-dependent mechanisms operating within a species can slow or stop population growth by decreasing birth rates or increasing death rates. 1st density-dependent: Competition for Resources

Competition for Resources Increasing population density leads to competition among members of a population for nutrients and other resources, reducing reproductive rates. Farmers minimize the effect of competition on the growth of wheat (Triticum aestivum) and other crops by applying fertilizers to reduce nutrient limitations on crop yield.

Animals also display a variety of morphological and physiological defensive adaptations. 1st example of Defensive Adaptations in Animals: cryptic coloration - define + example

Cryptic coloration, or camouflage, makes prey difficult to see example: canyon tree frog - see pic

Population Dynamics

Density: A Dynamic Perspective pg. 864 from book In some cases, population size and density can be determined by counting all individuals within the boundaries of the population. We could count all the sea stars in a tide pool, for instance. Large mammals that live in herds, such as elephants, can sometimes be counted accurately from airplanes. In most cases, however, it is impractical or impossible to count all individuals in a population. Instead, ecologists use various sampling techniques to estimate densities and total population sizes. They might count the number of oak trees in several randomly located 100×100 m plots, calculate the average density in the plots, and then extend the estimate to the population size in the entire area. Such estimates are most accurate when there are many sample plots and when the habitat is fairly homogeneous. In other cases, instead of counting single organisms, ecologists estimate density from an indicator of population size, such as the number of nests, burrows, tracks, or fecal droppings. Density is not a static (aka unchanged) property but changes as individuals are added to or removed from a population (Figure 40.15). Additions occur through birth (which we define here to include all forms of reproduction) and immigration, the influx of new individuals from other areas. The factors that remove individuals from a population are death (mortality) and emigration, the movement of individuals out of a population and into other locations. While birth and death rates influence the density of all populations, immigration and emigration also alter the density of many populations. For example, long-term studies of Belding's ground squirrels (Spermophilus beldingi) in the vicinity of Tioga Pass, in the Sierra Nevada of California, showed that some of the squirrels moved nearly 2 km from where they were born. This long-distance movement made them immigrants to other populations. In fact, immigrants made up 1-8% of the males and 0.7-6% of the females in the study population.

Laws of Thermodynamics

First Law • Total energy in the universe is constant • Energy can neither be created nor destroyed • Energy can be transferred or transformed read from book pg. 897 (relevance to ecology): Plants and other photosynthetic organisms convert solar energy to chemical energy, but the total amount of energy does not change: The energy stored in organic molecules must equal the total solar energy intercepted by the plant minus the amounts reflected and dissipated as heat. Ecosystem ecologists measure energy transfers within and across ecosystems, in part to understand how many organisms a habitat can support and the amount of food humans can harvest from a site. Second Law • Every energy transfer or transformation results in increased randomness (aka an increase in entropy) in the universe. read from book pg. 897 (relevance to ecology): One implication of this law is that energy conversions are inefficient. Some energy is always lost as heat. As a result, each unit of energy that enters an ecosystem eventually exits as heat. Thus, energy flows through ecosystems—it does not cycle within them for long periods of time. Because energy flowing through ecosystems is ultimately lost as heat, most ecosystems would vanish if the sun were not continuously providing energy to Earth.

A Hundred Heartbeats from Extinction

Flying Fox - Bat Yangtze River Dolphin Philippine Eagle These are two members of what Harvard biologist E. O. Wilson calls the Hundred Heartbeat Club, species with fewer than 100 individuals remaining on Earth. The Yangtze River dolphin may be extinct, but a few individuals were reportedly sighted in 2007.

Predict how changes to the abiotic or biotic environment can impact the carrying capacity (K) of a population.

From online: Limiting factors determine carrying capacity. The availability of abiotic factors (such as water, oxygen, and space) and biotic factors (such as food) dictates how many organisms can live in an ecosystem. In an ecosystem, the population of a species will increase until reaches the carrying capacity. Then the population size remains relatively the same. If abiotic or biotic factors change, the carrying capacity changes as well. Natural disasters can destroy resources in an ecosystem. If resources are destroyed, the ecosystem will not be able to support a large population. This causes the carrying capacity to decrease. Humans can also alter carrying capacity. Our activities can decrease or increase carrying capacity. We alter carrying capacity when we manipulate resources in a natural environment.

Ecosystem 1)

Generally: a complex network, or interconnected system biology definition from slides: a community of interacting organisms and their physical environment definition from the book pg. 896: the sum of all the organisms living in a given area and the abiotic factors with which they interact. 3 examples of ecosystems: 1) forest ecosystem - includes flora and fauna (plants and animals) 2) agro-ecosystem - also includes flora and fauna aka plants, weeds, and pests that come on them 3) urban ecosystems - people, plants animals, and structures that interact with each other

2nd density-dependent: Disease

If the transmission rate of a disease increases as a population becomes more crowded, then the disease's impact is density dependent. In humans, the respiratory diseases influenza (flu) and tuberculosis are spread through the air when an infected person sneezes or coughs. Both diseases strike a greater percentage of people in densely populated cities than in rural areas.

read - community

In Chapter 40, you learned how individuals within a population can affect other individuals of the same species. This chapter will examine ecological interactions between populations of different species. A group of populations of different species living in close enough proximity to interact is called a biological community. Ecologists define the boundaries of a particular community to fit their research questions: They might study the community of decomposers and other organisms living on a rotting log, the benthic community in Lake Superior, or the community of trees and shrubs in Sequoia National Park in California.

from book pg. 885 Trophic Structure example from lecture: Examples of Terrestrial and Marine Food Chains

In addition to species diversity, the structure and dynamics of a community also depend on the feeding relationships between organisms—the trophic structure of the community. The transfer of food energy from its source in plants and other autotrophs (primary producers) through herbivores (primary consumers) to carnivores (secondary, tertiary, and quaternary consumers) and eventually to decomposers is referred to as a food chain (Figure 41.14). The position an organism occupies in a food chain is called its trophic level. pic description: The arrows trace the transfer of food through the trophic levels of a community when organisms feed on one another. Decomposers, which consume the remains of organisms from all trophic levels, are not shown here.

Rachel Carson

In the 1960s, Rachel Carson brought attention to the biomagnification of DD T in birds in her book Silent Spring • Affected bird populations recovered following the 1971 ban of DDT in the United States pic description: Biologist and author Rachel Carson helped promote a new environmental ethic through her writing and her testimony before the U.S. Congress. Her efforts led to a ban on DDT use in the United States and stronger controls on the use of other chemicals. from book pg. 932: An infamous case of biological magnification that harmed top-level carnivores involved DDT, a chemical used to control insects such as mosquitoes and agricultural pests. In the decade after World War II, the use of DDT grew rapidly; its ecological consequences were not yet fully understood. By the 1950s, scientists were learning that DDT persists in the environment and is transported by water to areas far from where it is applied. One of the first signs that DDT was a serious environmental problem was a decline in the populations of pelicans, ospreys, and eagles, birds that feed at the top of food webs. The accumulation of DDT (and DDE, a product of its breakdown) in the tissues of these birds interfered with the deposition of calcium in their eggshells. When the birds tried to incubate their eggs, the weight of the parents broke the shells of affected eggs, resulting in catastrophic declines in the birds' reproduction rates. Rachel Carson's book Silent Spring helped bring the problem to public attention in the 1960s (Figure 43.23), and DDT was banned in the United States in 1971. A dramatic recovery in populations of the affected bird species followed.

Conservation Biology

Integrates several fields to conserve biological diversity • Ecology • Physiology • Molecular biology • Genetics • Evolutionary biology • Soil science • Agronomy • Hydrogeology from book: conservation biology, a discipline that integrates ecology, physiology, molecular biology, genetics, and evolutionary biology to conserve biological diversity at all levels. Efforts to sustain ecosystem processes and stem the loss of biodiversity also connect the life sciences with the social sciences, economics, and humanities.

4th density-dependent: (not on slides but review anyway) Intrinsic Factors

Intrinsic physiological factors (those operating within an individual organism) sometimes regulate population size. Reproductive rates of whitefooted mice (Peromyscus leucopus) in a field enclosure can drop even when food and shelter are abundant. This drop in reproduction at high population density is associated with aggressive interactions and hormonal changes within individual mice that delay sexual maturation and depress the immune system. These various examples of population regulation by negative feedback show how increased densities cause population growth rates to decline by affecting reproduction, growth, and survival. Although negative feedback helps explain why populations stop growing, it does not address why some populations fluctuate dramatically while others remain relatively stable.

Exploring Restoration Ecology Worldwide

Kissimmee River, Florida • Conversion of the Kissimmee River to a 90-k m canal caused the surrounding wetlands to dry up, threatening fish and bird populations • Filling part of the canal and reestablishing part of the river has helped restore the wetland ecosystem Maungatautari, New Zealand • Introduction of exotic mammals, including weasels, rats, and pigs, has threatened many native plant and animal species • Restoration efforts include building fences around reserves to exclude introduced species Succulent Karoo, South Africa • Overgrazing by livestock has damaged vast areas of land in this region • Restoration efforts have included revegetating the land and employing sustainable resource management Coastal Japan • Destruction of coastal seaweed and seagrass beds has threatened a variety of fishes and shellfish • Restoration efforts include constructing suitable seafloor habitat, transplanting and hand seeding seaweeds and seagrass

How Large Bodies of Water and Mountains Affect Climate

Large bodies of water: Because of the high specific heat of water, oceans and large lakes tend to moderate the climate of nearby land. For example, during a hot day, when land is warmer than the water, air over the land heats up and rises, drawing a cool breeze from the water across the land. In contrast, because temperatures drop more quickly over land than over water at night, air over the now warmer water rises, drawing cooler air from the land back out over the water and replacing it with warmer air from offshore. Mountains: Like large bodies of water, mountains influence air flow over land. When warm, moist air approaches a mountain, the air expands and cools as it rises, releasing moisture on the windward side of the peak. On the leeward side, cooler, dry air descends, absorbing moisture and producing a "rain shadow." Such leeward rain shadows determine where many deserts are found, including the Mojave Desert of western North America and the Gobi Desert of Asia. Mountains also affect the amount of sunlight reaching an area and thus the local temperature and rainfall. South-facing slopes in the Northern Hemisphere receive more sunlight than north-facing slopes and are therefore warmer and drier. These physical differences influence species distributions locally. On many mountains in western North America, spruce and other conifers grow on the cooler north-facing slopes, but shrubby, drought-resistant plants inhabit the south-facing slopes. In addition, every 1,000-m increase in elevation produces an average temperature drop of 6°C, equivalent to that produced by an 880-km increase in latitude. This is one reason that high-elevation communities near the equator, for example, can be similar to lower-elevation communities that are far from the equator. pic description: This figure illustrates what can happen on a hot summer day.

Global Climate Patterns (see pic) 1) _____ variation in _______ intensity is caused by ______ 2) say what dr. sata said 3) ______ strikes the ________ most directly 4) At higher latitudes, where sunlight __________ at _______ angle, light is _________

Latitudinal Variation in Sunlight Intensity: 1) Latitudinal Variation in Sunlight Intensity is caused by the curved shape of Earth (the Earth's tilt) 2) Global Climate Patterns including tropic, temperate, arctic, and antarctic, they're all due to the Earth's angle which creates this variation (including north and south pole where the sun approaches in a lower angle whereas in the tropics and subtropics the sun comes right overhead and a lot more intensity of the sun 3) Sunlight strikes the tropics, regions between 23.5° north and 23.5° south latitude, most directly 4) At higher latitudes, where sunlight strikes Earth at an oblique angle, light is more diffuse on Earth's surface

Threats to Biodiversity

Most species loss can be traced to four major threats: 1) Habitat loss: for urban and agricultural development (Ex. tropical forests destroyed in southeast Asia and South America) 2) Introduced species becoming invasive 3) Overharvesting for food or poaching for valuables (?) 4) Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems (aka global climate change)

Water Resources on Earth

Oceans 97.2% Ice Caps/Glaciers 2.0% Groundwater* 0.62% Freshwater Lakes 0.009% Inland seas/salt lakes 0.008% Atmosphere 0.001% Rivers 0.0001% TOTAL 99.8381% all this water is available for us to use. we use it mostly for agriculture (for food).

from book pg. 862: dispersal

One factor that contributes greatly to the global distribution of organisms is dispersal, the movement of individuals or gametes away from their area of origin or from centers of high population density. For example, while land-bound kangaroos have not reached North America under their own power, other organisms that disperse more readily, such as some birds, have. The dispersal of organisms is critical to understanding the role of geographic isolation in evolution (see Concept 22.2) as well as the broad patterns of species distribution that we see around the world today.

Make Connections: The Working Ecosystem pt. 2

Organisms transfer energy and matter in ecosystems (chapter 42) 8) Primary producers convert the energy in sunlight to chemical energy through photosynthesis. Their growth is often limited by abiotic factors such as low temperatures, scarce soil nutrients, and lack of light in winter. (See Figure 8.5, Figure 40.9, and Figure 42.4.) 9) Food chains are typically short in the tundra because primary production is lower than in most other ecosystems. (See Figure 41.14.) 10) Energy flows through ecosystems. When one organism eats another, only 10% of the energy transfers from one trophic level to the next. (See Figure 42.11.) 11) Detritivores recycle chemical elements back to primary producers. (See Figures 42.3 and 42.4.) 12) Chemical elements such as carbon and nitrogen move in cycles between the physical environment and organisms. (See Figure 42.15.)

Make Connections: The Working Ecosystem pt. 1 (READ PICS)

Populations are dynamic (Chapter 40) 1) Populations change in size through births and deaths and through immigration and emigration. Caribou migrate across the tundra to give birth at their calving grounds each year. (See Figure 40.15.) 2) Snow geese and many other species migrate to the Arctic each spring for the abundant food found there in summer. (See Concept 39.3.) 3) Birth and death rates influence the density of all populations. Death in the tundra comes from many causes, including predation, competition for resources, and lack of food in winter. (See Figure 40.25.) Species interact in diverse ways (Chapter 41) 4) In predation, an individual of one species kills and eats another. (See Concept 41.1.) 5) In herbivory, an individual of one species eats part of a plant or other primary producer, such as a caribou eating a lichen. (See Concept 41.1.) 6) In mutualism, individuals of two species interact in ways that benefit each other. In some mutualisms, the partners live in direct contact, forming a symbiosis; for example, a lichen is a symbiotic mutualism between a fungus and an alga or cyanobacterium. (See Concept 41.1 and Figure 26.30.) 7) In competition, individuals seek to acquire the same limiting resources. For example, snow geese and caribou both eat cottongrass. (See Concept 41.1.) (more aka steps 8-12 continued on next Quizlet term)

Positive Interactions in New England Salt Marshes

Positive interactions can have large effects on ecological communities. For instance, the black rush Juncus gerardii makes the soil more hospitable for other plant species in some areas of New England salt marshes (Figure 41.11a). Juncus helps prevent salt buildup in the soil by shading the soil surface, which reduces evaporation. Juncus also prevents the salt marsh soils from becoming oxygen depleted as it transports oxygen to its belowground tissues. In one study, when Juncus was removed from areas in the upper middle intertidal zone, those areas supported 50% fewer plant species pic description: When black rush (Juncus gerardii) is present, soil salt concentrations drop and soil oxygen levels rise, increasing the number of plant species that can live in the upper middle zone of the marsh.

Earth's Biodiversity Hot Spots

Preserving Biodiversity Hot Spots from dr. sata: many biodiversity hot spots are in tropical and subtropical areas In deciding which areas are of highest conservation priority, biologists often focus on biodiversity hot spots. A biodiversity hot spot is a relatively small area with numerous endemic species (species found nowhere else in the world) and a large number of endangered and threatened species. Nearly 30% of all bird species can be found in hot spots that make up only about 2% of Earth's land area. Together, the "hottest" of the terrestrial biodiversity hot spots total less than 1.5% of Earth's land but are home to more than a third of all species of plants, amphibians, reptiles (including birds), and mammals. Aquatic ecosystems also have hot spots, such as coral reefs and certain river systems. Biodiversity hot spots are good choices for nature reserves, but identifying them is not always simple. One problem is that a hot spot for one taxonomic group, such as butterflies, may not be a hot spot for some other taxonomic group, such as birds. Designating an area as a biodiversity hot spot is often biased toward saving vertebrates and plants, with less attention paid to invertebrates and microorganisms. Some biologists are also concerned that the hot-spot strategy places too much emphasis on such a small fraction of Earth's surface. Climate change makes the task of preserving hot spots even more challenging because the conditions that favor a particular community may not be found in the same location in the future. The biodiversity hot spot in the southwest corner of Australia holds thousands of species of endemic plants and numerous endemic vertebrates. Researchers recently concluded that between 5% and 25% of the plant species they examined may become extinct by 2080 because the plants will be unable to tolerate the increased dryness predicted for this region.

3rd example of Defensive Adaptations in Animals: Batesian mimicry

Some prey species are protected by their resemblance to other species. For example, in Batesian mimicry, a palatable or harmless species mimics an unpalatable or harmful species to which it is not closely related. example: The larva of the hawkmoth Hemeroplanes ornatus puffs up its head and thorax when disturbed, looking like the head of a small venomous snake

read: abiotic factors from the book pg. 863

Temperature Environmental temperature is an important factor in the distribution of organisms because of its effect on biological processes. Cells may rupture if the water they contain freezes (at temperatures below 0°C), and the proteins of most organisms denature at temperatures above 45°C. Most organisms function best within a specific range of environmental temperature. As discussed in Concept 1.1, climate change has caused hundreds of species to alter their geographic ranges—and a shift in the range of one species can profoundly affect other species. Consider how rising sea temperatures have changed the range of the sea urchin C. rodgersii. Since 1950, water temperatures along the coast of Tasmania, an island south of mainland Australia, have risen from 11.5°C to 12.5°C. This has enabled C. rodgersii—whose larvae fail to develop properly if temperatures drop below 12°C—to expand its range to the south (Figure 40.14). The urchin is a voracious consumer of kelp and other algae. As a result, algal communities that once harbored a rich diversity of other species have been completely destroyed in regions where the urchin has become well established (denoted by a solid orange line in Figure 40.14). Water and Oxygen The dramatic variation in water availability among habitats is another important factor in species distribution. Species living at the seashore or in tidal wetlands can desiccate (dry out) as the tide recedes. Terrestrial organisms face a nearly constant threat of desiccation, and the distribution of terrestrial species reflects their ability to obtain and retain water. Oxygen diffuses slowly in water. As a result, its concentration can be low in certain aquatic systems and soils, limiting cellular respiration and other physiological processes. Oxygen concentrations can be particularly low in deep ocean and deep lake waters, as well as in sediments where organic matter is abundant. Salinity The salt concentration of water in the environment affects the water balance of organisms through osmosis. Most aquatic organisms are restricted to either freshwater or saltwater habitats by their limited ability to osmoregulate (see Concept 32.4). Most terrestrial organisms can excrete excess salts from specialized glands or in feces or urine. However, the salt concentrations in some habitats (such as salt flats) are so high that few species of plants or animals can survive there. Sunlight Sunlight provides the energy that drives most ecosystems, and too little sunlight can limit the distribution of photosynthetic species. In forests, shading by leaves makes competition for light especially intense, particularly for seedlings growing on the forest floor. In aquatic environments, most photosynthesis occurs near the surface, where sunlight is more available. Rocks and Soil On land, the pH, mineral composition, and physical structure of rocks and soil limit the distribution of plants and therefore that of the animals that feed on them. The pH of soil can limit the distribution of organisms directly, through extreme acidic or basic conditions, or indirectly, by affecting the solubility of nutrients and toxins. In a river, the composition of rocks and soil that make up the substrate (riverbed) can affect water chemistry, which in turn influences the resident organisms. In freshwater and marine environments, the structure of the substrate determines the organisms that can attach to it or burrow into it.

3rd density-dependent: Territoriality

Territoriality can limit population density when space becomes the resource for which individuals compete. Cheetahs (Acinonyx jubatus) use a chemical marker in urine to warn other cheetahs of their territorial boundaries. The presence of surplus, or nonbreeding, individuals is a good indication that territoriality is restricting population growth.

Biological Processes Driving an Extinction Vortex

The Extinction Vortex: Evolutionary Implications of Small Population Size EVOLUTION A small population is vulnerable to inbreeding and genetic drift, which can draw the population down an extinction vortex toward smaller and smaller population size until no individuals survive (Figure 43.11). A key factor driving the extinction vortex is the loss of genetic variation that can enable evolutionary responses to environmental change, such as the appearance of new strains of pathogens. Both inbreeding and genetic drift can cause a loss of genetic variation (see Concept 21.3), and their effects become more harmful as a population shrinks. Inbreeding often reduces fitness because offspring are more likely to be homozygous for harmful recessive traits. Not all small populations are doomed by low genetic diversity, and low genetic variability does not automatically lead to permanently small populations. For instance, overhunting of northern elephant seals in the 1890s reduced the species to only 20 individuals—clearly a bottleneck with reduced genetic variation. Since that time, however, the northern elephant seal populations have rebounded to about 150,000 individuals today, though their genetic variation remains relatively low. Case Study: The Greater Prairie Chicken and the Extinction Vortex When Europeans arrived in North America, the greater prairie chicken (Tympanuchus cupido) was common from New England to Virginia and across the western prairies of the continent. Land cultivation for agriculture fragmented the populations of this species, and its abundance decreased rapidly (see Figure 21.11). Illinois had millions of greater prairie chickens in the 19th century but fewer than 50 by 1993. Researchers found that the decline in the Illinois population was associated with reduced genetic variation and a decrease in fertility. As a test of the extinction vortex hypothesis, scientists increased genetic variation by importing 271 birds from larger populations elsewhere (Figure 43.12). The Illinois population rebounded, indicating that it had been on its way to extinction until rescued by the transfusion of genetic variation.

book pg. 904 on pyramids

The loss of energy with each transfer in a food chain can be represented by an energy pyramid, in which the net productions of different trophic levels are arranged in tiers (Figure 42.11). The width of each tier is proportional to the net production, expressed in joules, of each trophic level. The highest level, which represents top-level predators, contains relatively few individuals. The small population size typical of top predators is one reason they tend to be vulnerable to extinction (and to the evolutionary consequences of small population size; see Concept 21.3). One important ecological consequence of low trophic efficiencies is represented in a biomass pyramid, in which each tier represents the total dry mass of all organisms in one trophic level. Most biomass pyramids narrow sharply from primary producers at the base to top-level carnivores at the apex because energy transfers between trophic levels are so inefficient (Figure 42.12a). Certain aquatic ecosystems, however, have inverted biomass pyramids: Primary consumers outweigh the producers Such inverted biomass pyramids occur because the producers—phytoplankton—grow, reproduce, and are consumed so quickly by the zooplankton that their total biomass remains at comparatively low levels. However, because the phytoplankton continually replace their biomass at such a rapid rate, they can support a biomass of zooplankton bigger than their own biomass. Likewise, because phytoplankton reproduce so quickly and have much higher production than zooplankton, the pyramid of energy for this ecosystem is still bottom-heavy, like the one in Figure 42.11. The dynamics of energy flow through ecosystems have implications for human consumers. For example, eating meat is a relatively inefficient way of tapping photosynthetic production. The same pound of soybeans that a person could eat for protein produces only a fifth of a pound of beef or less when fed to a cow. Worldwide agriculture could, in fact, feed many more people and require less land if we all fed more efficiently—as primary consumers, eating plant material pic description: Numbers denote the dry mass of all organisms at each trophic level..

Latitude

The numbering system used to indicate the location of parallels drawn on a globe and measuring distance north and south of the equator (it's horizontal lines from north to south)

Biological Magnification of PCBs in a Great Lakes Food Web (innfo from book pg. 932)

Toxins in the Environment Humans release an immense variety of toxic chemicals, including thousands of synthetic compounds previously unknown in nature, with little regard for the ecological consequences. Organisms acquire toxic substances from the environment along with nutrients and water. Some of the poisons are metabolized or excreted, but others accumulate in specific tissues, often fat. One of the reasons accumulated toxins are particularly harmful is that they become more concentrated in successive trophic levels of a food web. This phenomenon, called biological magnification, occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below. Thus, top-level carnivores tend to be most severely affected by toxic compounds in the environment. Chlorinated hydrocarbons are a class of industrially synthesized compounds that have demonstrated biological magnification. Chlorinated hydrocarbons include the industrial chemicals called PCBs (polychlorinated biphenyls) and many pesticides, such as DDT. Current research implicates many of these compounds in endocrine system disruption in numerous animal species, including humans. Biological magnification of PCBs has been found in the food web of the Great Lakes, where the concentration of PCBs in herring gull eggs, at the top of the food web, is nearly 5,000 times that in phytoplankton, at the base (Figure 43.22). An infamous case of biological magnification that harmed top-level carnivores involved DDT, a chemical used to control insects such as mosquitoes and agricultural pests. In the decade after World War II, the use of DDT grew rapidly; its ecological consequences were not yet fully understood. By the 1950s, scientists were learning that DDT persists in the environment and is transported by water to areas far from where it is applied. One of the first signs that DDT was a serious environmental problem was a decline in the populations of pelicans, ospreys, and eagles, birds that feed at the top of food webs. The accumulation of DDT (and DDE, a product of its breakdown) in the tissues of these birds interfered with the deposition of calcium in their eggshells. When the birds tried to incubate their eggs, the weight of the parents broke the shells of affected eggs, resulting in catastrophic declines in the birds' reproduction rates. Rachel Carson's book Silent Spring helped bring the problem to public attention in the 1960s (Figure 43.23), and DDT was banned in the United States in 1971. A dramatic recovery in populations of the affected bird species followed.

Where are trade winds located?

around the equator

Commensalism Between Cattle Egrets (Bubulcus Ibis) and an African Buffalo (Syncerus Caffer)

cattle egrets feed on insects flushed out of the grass by grazing bison, cattle, and other herbivores (Figure 41.10). Because the birds typically find more prey when they follow herbivores, they clearly benefit from the association. Much of the time, the herbivores are not affected by the birds. At times, however, the herbivores too may derive some benefit; the birds may remove and eat ticks and other ectoparasites from their skin or they may warn the herbivores of a predator's approach. This example illustrates another key point about ecological interactions: Their effects can change over time. In this case, an interaction whose effects are typically +/0 (commensalism) may at times become +/+ (mutualism).

Video: Clownfish and Anemone

clownfish gets a safe home inside the anemone, no other organism wants to be stung by the anemone which has horrible stinging cells. waste products of clownfish are high in nitrogen which fertilizes the anemone and allows its symbionts to do photosynthesis

Flowchart of Factors Limiting Geographic Distribution

ecology definition from google: the branch of biology that deals with the relations of organisms to one another and to their physical surroundings. So far in this chapter, we've examined Earth's climate and the characteristics of terrestrial and aquatic biomes. We've also introduced the range of biological levels at which ecologists work (see Figure 40.2). In this section, we'll examine how ecologists determine what factors control the distribution of species. Broadly speaking, species distributions are a consequence of both ecological factors and evolutionary history. Consider kangaroos, which are found in Australia and nowhere else in the world. Fossil evidence indicates that kangaroos and their close relatives originated in Australia, roughly 5 million years ago. By that time, Australia had moved close to its present location (by continental drift; see Concept 23.2), and it was not connected to other landmasses. Thus, kangaroos occur only in Australia in part because of an accident of history: The kangaroo lineage originated there at a point in time when the continent was geographically isolated. But ecological factors are also important. To date, kangaroos have not dispersed (on their own) to other continents; hence, they are restricted to the continent on which they originated. And within Australia, kangaroos are found in some habitats but not in others. The red kangaroo, for example, occurs in the arid grasslands of central Australia, but not in the tall, open forests of eastern Australia. Such observations can lead us to ask whether food availability, predators, temperature, or other factors cause red kangaroos to be found in some regions but not others. As our discussion of kangaroos suggests, ecologists ask not only where species occur, but also why species occur where they do: What factors determine their distribution? Ecologists generally need to consider multiple factors and alternative hypotheses when attempting to explain the distribution of a species. We'll focus here on the ecological factors highlighted by the questions in the flowchart in Figure 40.12. pic description: An ecologist studying factors limiting a species' distribution might consider questions like these. As suggested by the arrows leading from the "Yes" responses, the ecologist would answer all of these questions because more than one of these factors can limit a species' distribution.

biome - evelyn's definition

entire community of species that live in a distinct habitat; typically organized according to climate

Population Growth Predicted by the Logistic Model

from book: In the logistic population growth model, the per capita rate of population growth approaches zero as the population size nears the carrying capacity • Population growth slows when the population size is greater than half the carrying capacity (which is K/2) (from dr. sata: when the population reaches half the carrying capacity which is k/2, the population growth slows down and levels off and reaches a plateau) • Growth stops when the population size equals K • The logistic model of population growth produces a sigmoid (S-shaped) curve pic description: The rate of population growth decreases as population size (N) approaches the carrying capacity (K) of the environment. The red line shows logistic growth in a population where r=1.0 and K=1,500 individuals. For comparison, the blue line illustrates a population continuing to grow exponentially with the same r.

water cycle steps from google

evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater 1) Evaporation - Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. 2) transpiration - evaporation of liquid water from plants and trees into the atmosphere. 3) condensation - the process where water vapor (a gas) changes into water droplets (a liquid). This is when we begin to see clouds 4) precipitation - is water that falls to the earth. Most precipitation falls as rain but includes snow, sleet, drizzle, and hail. 5) movement through surface and groundwater - Infiltration is the movement of water into the ground from the surface. Percolation is movement of water past the soil going deep into the groundwater. Surface flow is the river, lake, and stream transport of water to the oceans. Groundwater is the flow of water under- ground in aquifers. The water may return to the surface in springs or eventually seep into the oceans. Plant uptake is water taken from the groundwater flow and soil moisture. https://www.weather.gov/media/jetstream/downloads/hydro2010.pdf

Carbon Cycle Steps from quizlet

first version from quizlet: - Plant leaves take carbon dioxide from air - Plants store carbon in carbohydrates or starches - photosynthesis) - Plants & animals release carbon dioxide back into the air (cellular respiration) - Decomposers return carbon to environment (decomposition) second version from quizlet: 1. Carbon enters the atmosphere as carbon dioxide from respiration and combustion. 2. Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis. 3. Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals and plants eventually die. 4. The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.

Make Connections: Climate Change Has Effects at All Levels of Biological Organization pt. 1: Effects on Cells (info to understand not memorize)

from book - Effects on Cells Temperature affects the rates of enzymatic reactions (see Figure 6.16), and as a result, the rates of DNA replication, cell division, and other key processes in cells are affected by rising temperatures. Global warming and other aspects of climate change have also impaired some organisms' defense responses at the cellular level. For example, in the vast coniferous forests of western North America, climate change has reduced the ability of pine trees to defend themselves against attack by the mountain pine beetle (Dendroctonus ponderosae). from slide: When beetles overwhelm a tree's cellular defenses, they produce large numbers of offspring that tunnel through the wood, causing extensive damage. Rising temperatures have shortened how long it takes beetles to mature and reproduce, resulting in even more beetles. The beetles can also infect the tree with a harmful fungus, which appears as blue stains on the wood. Pine defenses include specialized resin cells that secrete a sticky substance (resin) that can entrap and kill mountain pine beetles. Resin cells produce less resin in trees that are stressed by rising temperatures and drought conditions. This aerial view shows the scope of destruction in one North American forest due to mountain pine beetles; dead trees appear orange and red.

Climate Change Effects on Communities and Ecosystems (info to understand not memorize)

from book - Effects on Communities and Ecosystems Climate affects where species live (see Figure 40.8). Climate change has caused hundreds of species to move to new locations, in some cases leading to dramatic changes in ecological communities. Climate change has also altered primary production (see Figure 25.25) and nutrient cycling in ecosystems. In the example we discuss here, rising temperatures have enabled a sea urchin to invade southern regions along the coast of Australia, causing catastrophic changes to marine communities there. from slide: The sea urchin Centrostephanus rodgersii requires water temperatures above 12°C to reproduce successfully, as shown in this graph. As ocean waters rise above this critical temperature, the urchin has been able to expand its range to the south, destroying kelp beds as it moves into new regions. As the urchin has expanded its range to the south, it has destroyed high-diversity kelp communities, leaving bare regions called "urchin barrens" in its wake.

Climate Change Effects on Individual Organisms (info to understand not memorize)

from book - Effects on Individual Organisms Organisms must maintain relatively constant internal conditions (see Concept 32.3); for example, an individual will die if its body temperature becomes too high. Global warming has increased the risk of overheating in some species, leading to reduced food intake and reproductive failure. For instance, an American pika (Ochotona princeps) will die if its body temperature rises just 3°C above its resting temperature—and this can happen quickly in regions where climate change has already caused significant warming. from slide: As summer temperatures have risen, American pikas are spending more time in their burrows to escape the heat. Thus, they have less time to forage for food. Lack of food has caused mortality rates to increase and birth rates to drop. Pika populations have dwindled, some to the point of extinction. (See Figure 1.11 for another example.) This graph represents conditions in 2015 at 67 sites that previously supported a pika population; the populations at 10 of these sites had become extinct. Most extinctions occurred at sites with high summer temperatures and a small area of pika habitat. As temperatures continue to increase, more extinctions are expected.

Climate Change Effects on Populations (info to understand not memorize)

from book - Effects on Populations Climate change has caused some populations to increase in size, while others have declined (see Concept 1.1 and Concept 36.1). In particular, as the climate has changed, some species have adjusted when they grow, reproduce, or migrate—but others have not, causing their populations to face food shortages and reduced survival or reproductive success. In one example, researchers have documented a link between rising temperatures and declining populations of caribou (Rangifer tarandus) in the Arctic. from slide: Caribou populations migrate north in the spring to give birth and to eat sprouting plants. Alpine chickweed is an early-flowering plant on which caribou depend. As the climate has warmed, the plants on which caribou depend have emerged earlier in the spring. Caribou have not made similar changes in the timing of when they migrate and give birth. As a result, there is a shortage of food, and caribou offspring production has dropped fourfold.

A Climograph for Some Major Types of Biomes in North America

from book pg. 854: Factors other than mean temperature and precipitation also play a role in determining where biomes exist. For example, some areas in North America with a particular combination of temperature and precipitation support a temperate broadleaf forest, but other areas with similar values for these variables support a coniferous forest (see the overlap in Figure 40.8). One reason for this variation is that climographs are based on annual averages, but the pattern of climatic variation is often as important as the average climate. For example, some areas may receive regular precipitation throughout the year, whereas other areas may have distinct wet and dry seasons. Natural and human-caused disturbances also alter the distribution of biomes. A disturbance is an event such as a storm, fire, or human activity that changes a community, removing organisms from it and altering resource availability. For instance, frequent fires can kill woody plants and keep a savanna from becoming the woodland that climate alone would support. Hurricanes and other storms create openings for new species in many tropical and temperate forests. Human-caused disturbances have altered much of Earth's surface, replacing natural communities with urban and agricultural ones from dr. sata: tropical forests get the most precipitation. Temperature is very high in deserts and precipitation is very low (same in grassland i think high temp low precipitation) forests have high temp and decent precipitation pic description: The areas plotted here encompass the ranges of annual mean temperature and precipitation in the biomes.

Patterns of Dispersion Within a Population's Geographic Range (SEE PIC)

from book pg. 865: Patterns of Dispersion Within a population's geographic range, local densities may differ substantially, creating contrasting patterns of dispersion. Differences in local density are among the most important characteristics for a population ecologist to study since they provide insight into the biotic and abiotic factors that affect individuals in the population. The most common pattern of dispersion is clumped, in which individuals are aggregated in patches. Plants and fungi are often clumped where soil conditions and other environmental factors favor germination and growth. Mushrooms, for instance, may be clumped within and on top of a rotting log. Insects and salamanders may be clumped under the same log because of the higher humidity there. Clumping of animals may also be associated with mating behavior. Sea stars group together in tide pools, where food is readily available and where they can breed successfully (Figure 40.16a). The aggregation of individuals into groups may also increase the effectiveness of predation or defense; for example, a wolf pack is more likely than a single wolf to subdue a moose, and a flock of birds is more likely than a single bird to warn of a potential attack. from pic on slides: (a) Clumped. Sea stars group together where food is abundant (b) Uniform. King penguins and other birds that nest on small islands often exhibit uniform spacing, maintained by aggressive interactions between neighbors. (c) Random. Dandelions grow from windblown seeds that land at random and later germinate.

Idealized Survivorship Curves: Types I, II, and III

from book pg. 866: The survival rate data in a life table can be represented graphically as a survivorship curve, a plot of the proportion or numbers in a cohort still alive at each age. Often, a survivorship curve begins with a cohort of a convenient size—say, 1,000 individuals. Though diverse, survivorship curves can be classified into three general types Survivorship curves can be classified into three general types: • Type I: high survivorship during early and middle life followed by a steep drop due to increase in death rates among older age groups (ex. humans lifespan begins to decline after 50 yrs of age then rapidly decline after 80-90) • Type II: survivorship declines linearly due to a constant death rate over the organism's life span (steady decline overtime) • Type III: low survivorship due to high death rates for young age-groups and stable survivorship later in life due to a lower death rate for survivors (ex. oysters) most animals are either type 1 or 2 pic description: The y-axis is logarithmic and the x-axis is on a relative scale so that species with widely varying life spans can be presented together on the same graph.

Figure 40.26 Fluctuations in Moose and Wolf Population Sizes on Isle Royale, 1959-2011

from book pg. 873 Stability and Fluctuation Populations of large mammals were once thought to remain relatively stable, but long-term studies have challenged that idea. For instance, the moose population on Isle Royale in Lake Superior has fluctuated substantially since around 1900. At that time, moose from the Ontario mainland (25 km away) colonized the island, perhaps by walking across the lake when it was frozen. Wolves, which rely on moose for most of their food, reached the island around 1950 by walking across the frozen lake. The lake has not frozen over since the early 1950s, and both populations appear to have been isolated from immigration and emigration since then. Despite this isolation, the moose population experienced two major increases and collapses during the last 50 years What factors cause the size of the moose population to change so dramatically? Harsh weather, particularly cold winters with heavy snowfall, can weaken moose and reduce food availability, decreasing the population size. When moose numbers are low and the weather is mild, food is readily available and the population grows quickly. Conversely, when moose numbers are high, factors such as predation and an increase in the density of ticks and other parasites cause the population to shrink. The effects of some of these factors can be seen in Figure 40.26. The first collapse coincided with a peak in the numbers of wolves from 1975 to 1980. The second major collapse, around 1995, coincided with harsh winter weather, which increased the energy needs of the animals and made it harder for the moose to find food under the deep snow.

Overview of Energy and Nutrient Dynamics in an Ecosystem 1) ecologists group species in an ecosystem into _____ based on _____ primary producers 2 pt. 1) define 2 pt. 2) most ______ are ______ that use ______ 2 pt. 3) the most common _____ are (3) 2 pt. 4) what are primary producers in deep-sea hydrothermal vents 3) Organisms in trophic levels above the primary producers are _____, which _______ 4) primary consumers - define 5) secondary consumers - define 6) tertiary consumers - define 7) decomposers - define 8) detritus - define 9) the most important detritivores are (2) + why

from book pg. 897: Energy, Mass, and Trophic Levels 1) Ecologists group species in an ecosystem into trophic levels (trophic level def - Each step in a food chain or food web) based on feeding relationships 2 pt. 1) The trophic level that ultimately supports all others consists of autotrophs, also called the primary producers of the ecosystem. 2 pt. 2) Most autotrophs are photosynthetic organisms that use light energy to synthesize sugars and other organic compounds, which they use as fuel for cellular respiration and as building material for growth. 2 pt. 3) The most common autotrophs are plants, algae, and photosynthetic prokaryotes (from dr. sata - know primary producers are plants) 2 pt. 4) although chemosynthetic prokaryotes are the primary producers in ecosystems such as deep-sea hydrothermal vents (see Figure 40.11) and places deep underground or beneath ice. 3) Organisms in trophic levels above the primary producers are heterotrophs, which depend directly or indirectly on the primary producers for their source of energy. 4) Herbivores, which eat plants and other primary producers, are primary consumers. 5) Carnivores that eat herbivores are secondary consumers 6) and carnivores that eat other carnivores are tertiary consumers. 7) Another group of heterotrophs is the detritivores, or decomposers, terms used synonymously in this text to refer to consumers that get their energy from detritus. 8) Detritus is nonliving organic material, such as the remains of dead organisms, feces, and fallen leaves. 9) Although some animals eat detritus, the most important detritivores are prokaryotes and fungi. These organisms secrete enzymes that digest organic material; they then absorb the breakdown products. Many detritivores are in turn eaten by secondary and tertiary consumers. In a forest, for instance, birds eat earthworms that have been feeding on leaf litter and its associated prokaryotes and fungi. As a result, chemicals originally synthesized by plants pass from plants to leaf litter to detritivores to birds. By recycling chemical elements to producers, detritivores also play a key role in the trophic relationships of an ecosystem (Figure 42.4). Detritivores convert organic matter from all trophic levels to inorganic compounds usable by primary producers. When the detritivores excrete waste products or die, those inorganic compounds are returned to the soil. Producers can then absorb these elements and use them to synthesize organic compounds. If decomposition stopped, life as we know it would cease as detritus piled up and the supply of ingredients needed to synthesize organic matter was exhausted. pic description: Energy enters, flows through, and exits an ecosystem, whereas chemical nutrients cycle within it. Energy (dark orange arrows) entering from the sun as radiation is transferred as chemical energy through the food web; each of these units of energy ultimately exits as heat radiated into space. Most transfers of nutrients (blue arrows) through the food web lead eventually to detritus; the nutrients then cycle back to the primary producers.

Controlled Environment Agriculture

quizlet definition: The production of plants and their products inside greenhouses, growth chambers, or any totally enclosed structures providing control of the aerial environment • Greenhouse - A greenhouse will allow growers to lower operating costs by providing crops with natural light and ventilation, and when designed correctly, greenhouses also allow for the optimal use of the CEA equipment and ensure the structural strength for hanging heaters, and fans, and other CEA tools. • Hot house • Warehouses

Biodiversity Variables (said we don't need to worry about this entire table, just know 1st and 2nd column??)

see pic

seasonal changes are primarily due to

the earth's tilt

Determining Primary Production with Satellites

from book pg. 898: In most ecosystems, the amount of light energy converted to chemical energy—in the form of organic compounds—by autotrophs during a given time period is the ecosystem's primary production. In ecosystems where the primary producers are chemoautotrophs, the initial energy input is chemical, and the initial products are the organic compounds synthesized by the microorganisms. from book pg. 899 Gross and Net Production Total primary production in an ecosystem is known as that ecosystem's gross primary production (GPP)—the amount of energy from light (or chemicals, in chemoautotrophic systems) converted to the chemical energy of organic molecules per unit time. Not all of this production is stored as organic material in the primary producers because they use some of the molecules as fuel for their own cellular respiration. Net primary production (NPP) is equal to gross primary production minus the energy used by the primary producers (autotrophs) for their cellular respiration (Ra, where "a" stands for autotrophs): NPP = GPP - Ra from dr. sata: how is energy from the sun reflected? what is the wavelength that is available? point of this graph: how much solar energy is consumed and what range of the wavelength comes in? from book on graph pg. 899 Satellites provide a powerful tool for studying global patterns of primary production (Figure 42.5). Images produced from satellite data show that different ecosystems vary considerably in their NPP. For example, tropical rain forests are among the most productive terrestrial ecosystems and contribute a large portion of the planet's NPP. Estuaries and coral reefs also have very high NPP, but their contribution to the global total is smaller because these ecosystems cover only about one-tenth the area covered by tropical rain forests. In contrast, while the open oceans are relatively unproductive (Figure 42.6), their vast size means that together they contribute as much global NPP as terrestrial systems do. Figure 42.5 Research Method Determining Primary Production with Satellites Application Because chlorophyll captures visible light, photosynthetic organisms absorb more light at visible wavelengths (about 380−750 nm) than at near-infrared wavelengths (750−1,100 nm). Scientists use this difference in absorption to estimate the rate of photosynthesis in different regions using satellites. Technique Most satellites "see" by comparing the ratios of wavelengths reflected back to them. Vegetation produces a very different pattern from that of snow, clouds, soil, and liquid water. Results Scientists use the satellite data to help produce maps of primary production like the one in Figure 42.6

Light Limitation and Zonation in a Lake

from book pg. 900 but basically the same as thr lecture slides: Because solar radiation drives photosynthesis, you would expect light to be a key variable in controlling primary production in oceans. Indeed, the depth of light penetration affects primary production throughout the photic zone of an ocean or lake. About half of the solar radiation is absorbed in the first 15 m of water. Even in "clear" water, only 5−10% of the radiation may reach a depth of 75 m. If light were the main variable limiting primary production in the ocean, primary production would be expected to increase from the poles toward the equator, which receives the greatest intensity of light. However, you can see in Figure 42.6 that there is no such gradient. What other factor strongly influences primary production in the ocean? (it's nutrients lol)

Limitation of Water and Net Primary Production

from book pg. 900: Primary Production in Terrestrial Ecosystems At regional and global scales, temperature and moisture are the main factors controlling primary production in terrestrial ecosystems. Tropical rain forests, with their warm, wet conditions that promote plant growth, are the most productive terrestrial ecosystems. In contrast, low-productivity systems are generally hot and dry, like many deserts, or cold and dry, like arctic tundra. Between these extremes lie the temperate forest and grassland ecosystems, with moderate climates and intermediate productivity. The climate variables of precipitation and temperature are very useful for predicting NPP in terrestrial ecosystems. For example, primary production is greater in wetter ecosystems, as shown for the plot of NPP and annual precipitation in Figure 42.8. (see pic) NPP also increases with temperature and the amount of solar energy available to drive evaporation and transpiration.

Nutrient Cycling in the Hubbard Brook Experimental Forest An Example of Long-Term Ecological Research

from book pg. 910 Case Study: Nutrient Cycling in the Hubbard Brook Experimental Forest Since 1963, ecologist Gene Likens and colleagues have been studying nutrient cycling at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Their research site is a deciduous forest that grows in six small valleys, each drained by a single creek. Impermeable bedrock underlies the soil of the forest. The research team first determined the mineral budget for each of six valleys by measuring the input and outflow of several key nutrients. They collected rainfall at several sites to measure the amount of water and dissolved minerals added to the ecosystem. To monitor the loss of water and minerals, they constructed a small concrete dam with a V-shaped spillway across the creek at the bottom of each valley (Figure 42.16a). They found that about 60% of the water added to the ecosystem as rainfall and snow exits through the stream, and the remaining 40% is lost by evapotranspiration. Preliminary studies confirmed that internal cycling conserved most of the mineral nutrients in the system. For example, only about 0.3% more calcium (Ca2+) leaves a valley via its creek than is added by rainwater, and this small net loss is probably replaced by chemical decomposition of the bedrock. During most years, the forest even registers small net gains of a few mineral nutrients, including nitrogen. Experimental deforestation of a watershed dramatically increased the flow of water and minerals leaving the watershed (Figure 42.16b). Over three years, water runoff from the newly deforested watershed was 30-40% greater than in a control watershed, apparently because there were no plants to absorb and transpire water from the soil. Most remarkable was the loss of nitrate, whose concentration in the creek increased 60-fold, reaching levels considered unsafe for drinking water (Figure 42.16c). The Hubbard Brook deforestation study showed that the amount of nutrients leaving an intact forest ecosystem is controlled mainly by the plants. Retaining nutrients in an ecosystem helps to maintain the productivity of the system, as well as to avoid problems elsewhere, such as algal blooms caused by excess nutrient runoff that enters a downstream ecosystem. pic description: (c) The concentration of nitrate in runoff from the deforested watershed was 60 times greater than in a control (unlogged) watershed.

Per Capita Ecological Footprint by Country (he said we don't need this info for the exam? lol)

from book pg. 939 Limits on Human Population Size A more comprehensive approach to estimating the carrying capacity of Earth is to recognize that humans have multiple constraints: We need food, water, fuel, building materials, and other resources, such as clothing and transportation. The ecological footprint concept summarizes the aggregate land and water area required by each person, city, or nation to produce all the resources it consumes and to absorb all the waste it generates. What is a sustainable ecological footprint for the human population? One way to estimate this is to add up all the ecologically productive land on the planet and divide by the population. Typically, this estimate is made using global hectares, where a global hectare (gha) is defined as a hectare of land or water that is of world-average biological productivity (1 hectare=2.47 acres). This calculation yields an allotment of 1.7 gha per person—the benchmark for comparing actual ecological footprints. Anyone who consumes resources that require more than 1.7 gha to produce is using an unsustainable share of Earth's resources, as is the case for the citizens of many countries (Figure 43.31). For example, a typical ecological footprint for a person in the United States is 8 gha. Globally, the average footprint is 2.7 gha per person, more than a 50% overshoot of the sustainable use (1.7 gha per person) of Earth's resources. Our impact on the planet can also be assessed using currencies other than area, such as energy use. Average energy use differs greatly in developed and developing nations. A typical person in the United States, Canada, or Norway consumes roughly 30 times the energy that a person in central Africa does. Moreover, fossil fuels, such as oil, coal, and natural gas, are the source of 80% or more of the energy used in most developed nations. This unsustainable reliance on fossil fuels is changing Earth's climate and increasing the amount of waste that each of us produces. Ultimately, the combination of resource use per person and population density determines our global ecological footprint. How many people our planet can sustain depends on the quality of life each of us has and the distribution of wealth across people and nations, topics of great concern and political debate. We can decide whether zero population growth will be attained through social changes based on human choices or, instead, through increased mortality due to resource limitation, plagues, war, and environmental degradation.

To operate, all processes need energy. the primary source of energy for living organisms and other processes on earth come from where?

the sun

Source of Water for Animal Agriculture

what's wrong with using groundwater for animal agriculture? remember that animals require much more energy as they are endotherms so they need to eat lots of plants and need to consume lots of food which means they use lots of water

Resource Partitioning Among Dominican Republic Lizards

from book: the differentiation of niches that enables similar species to coexist in a community is called resource partitioning pic description from book - Seven species of Anolis lizards live in close proximity, and all feed on insects and other small arthropods. However, competition for food is reduced because each lizard species has a different preferred perch, thus occupying a distinct niche. (aka from Evelyn - if you're an organism and can avoid competition and still get access to the resources you need to survive, that's great. you don't want to have to work for it too hard. so different communities will occupy different niches that are kind of similar. for ex. in the picture, a lizard stays on the sunny fence and eats the insects in that area whereas the other lizard will perch on the shady branches and eat the bugs that go to the shady spot and no one has to get in a fight for what they want. overtime, traits will evolve to assist in resource partitioning.) read: book pg. 878 EVOLUTION Competition for limited resources can cause evolutionary change in populations. One way to examine how this occurs is to focus on an organism's ecological niche, the specific set of biotic and abiotic resources that an organism uses in its environment. The niche of a tropical tree lizard, for instance, includes the temperature range it tolerates, the size of branches on which it perches, the time of day when it is active, and the sizes and kinds of insects it eats. Such factors define the lizard's niche, or ecological role—how it fits into an ecosystem. We can use the niche concept to restate the principle of competitive exclusion: Two species cannot coexist permanently in a community if their niches are identical. However, ecologically similar species can coexist in a community if one or more significant differences in their niches arise through time. Evolution by natural selection can result in one of the species using a different set of resources or similar resources at different times of the day or year. The differentiation of niches that enables similar species to coexist in a community is called resource partitioning

Sustainability/ Sustainable Development

from dr. sata's slides: 1) Sustainability Definition "To create and maintain conditions, under which humans and nature can exist in productive harmony, that permit fulfilling the social, economic, and other requirements of present and future generations" NEPA (National Environmental Policy Act) 2) Sustainability is a goal and a process 3) Sustainable development goals: 1. Environmental: a viable natural environment 2. Social: nurturing community 3. Government: vision and direction, enabling conditions, set rules/regulations, public services, resources 4. Economic: has to be sufficient for the economy from book pg. 940: Sustainable Development We need to understand the interconnections of the biosphere if we are to protect species from extinction and improve the quality of human life. To this end, many nations, scientific societies, and other groups have embraced the concept of sustainable development, economic development that meets the needs of people today without limiting the ability of future generations to meet their needs. Achieving sustainable development is an ambitious goal. To sustain ecosystem processes and stem the loss of biodiversity, we must connect life science with the social sciences, economics, and the humanities. We must also reassess our personal values. Those of us living in wealthier nations have a larger ecological footprint than do people living in developing nations. By considering the long-term costs of consumption, we can learn to value the natural processes that sustain us.

Water and Nutrient Cycling

from dr. sata: combination of nitrogen cycle and water cycle is very critical. understand the individual cycles and how they work together and interact. couldn't find much on google about how they're related

nitrogen cycle (from google)

from google: 1. Nitrogen fixation (N2 to NH3/ NH4+ or NO3-) 2. Nitrification (NH3 to NO3-) 3. Assimilation (Incorporation of NH3 and NO3- into biological tissues) 4. Ammonification (organic nitrogen compounds to NH3) 5. Denitrification (NO3- to N2) also from google: 1. Nitrogen Fixation - Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium. 2. Nitrification - This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb. 3. Assimilation - This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll. 4. Ammonification - This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle. 5. Denitrification - Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task as well. https://www.ducksters.com/science/ecosystems/nitrogen_cycle.php

Irrigation Methods in the USA (he said for the graphs only learn how to interpret and apply them)

from linked website on lecture slide: According to a U.S. Geological Survey report, agriculture is a major user of ground and surface water in the United States, and irrigation accounted for 42 percent of the Nation's total freshwater withdrawals in 2015. Water applied as irrigation allows for crop production in arid regions and supplements soil moisture in humid regions when growing season precipitation is insufficient. Irrigation has enhanced both the productivity and profitability of the agricultural sector. According to the 2017 Census of Agriculture, farms with some form of irrigation accounted for more than 54 percent of the total value of U.S. crop sales, while irrigated land accounted for less than 20 percent of harvested cropland. Irrigated crop production helps to support local rural economies in many areas of the U.S., and contributes to the Nation's livestock, food processing, transportation, and energy sectors.

Determining Equilibrium for Population Density

from pic on slides: When the density is low, there are more births than deaths. Hence, the population grows until the density reaches Q. When the density is high, there are more deaths than births. Hence, the population shrinks until the density reaches Q. Bioflix Animation: Density Dependence: from video: density dependent factors that limit population size depend on the density of the population (how many individuals occupy a certain amount of space). density-dependent factors include limited food, limited breeding space, and predators. density independent factors don't depend on population density for example an oil spill affects all birds in the area regardless of their density population ecology helps us understand human population growth and where we might be headed next from book pg. 871: A birth rate or death rate that does not change with population density is said to be density independent. For example, researchers found that the mortality of dune fescue grass (Vulpia fasciculata) is mainly due to physical factors that kill similar proportions of a local population, regardless of its density. Drought stress that arises when the roots of the grass are uncovered by shifting sands is a density-independent factor that can kill these plants. In contrast, a death rate that increases with population density or a birth rate that falls with rising density is said to be density dependent. Researchers found that reproduction by dune fescue declines as population density increases, in part because water or nutrients become more scarce. Thus, the key factors affecting birth rate in this population are density dependent, while death rate is largely determined by density-independent factors. Figure 40.24 shows how the combination of density-dependent reproduction and density-independent mortality can stop population growth, leading to an equilibrium population density in species such as dune fescue. pic description: This simple model considers only birth and death rates. (Immigration and emigration rates are assumed to be either zero or equal.) In this example, the birth rate changes with population density, while the death rate is constant. At the equilibrium density (Q), the birth and death rates are equal.

Net Ecosystem Productivity (NEP): how can you measure it?

from slide: Turbulent exchange of CO2 between atmosphere and biosphere is measured from dr. sata: by looking at satellite images or by looking at the chlorophyll content by measuring carbon dioxide concentration going down during the daytime and up during the nighttime

Key Events of Global Warming

why should we be worried about global warming? there's lots of evidence (read the pic for them all) 1) amazon rainforest being destroyed has led to droughts 2) ice melting leading to rising sea levels which will leave cities underwater soon 3) forests being destroyed ex. california wildfires 4)

Natural Edges Between Ecosystems in Siberia

from slides: • Fragmentation increases edge habitat and reduces overall biodiversity, though edge-adapted species may increase • Parasites adapted to edge habitat can put further pressure on already vulnerable populations • The Biological Dynamics of Forest Fragments Project in the Amazon examines the effects of forest fragmentation on community structure • Results consistently show that species adapted to the forest interior decline in small patches • Landscapes dominated by small fragments will likely support fewer species from book pg. 927: Although conservation efforts have historically focused on saving individual species, efforts today often seek to sustain the biodiversity of entire communities, ecosystems, and landscapes Landscape Structure and Biodiversity The biodiversity of a given landscape is heavily influenced by its physical features, or structure. Understanding landscape structure is critically important in conservation because many species use more than one kind of ecosystem, and many live on the borders between ecosystems. Fragmentation and Edges The boundaries, or edges, between ecosystems—such as between a lake and the surrounding forest or between cropland and suburban housing tracts—are defining features of landscapes (Figure 43.15). An edge has its own set of physical conditions, which differ from those on either side of it. The soil surface of an edge between a forest patch and a burned area receives more sunlight and is usually hotter and drier than the forest interior, but it is cooler and wetter than the soil surface in the burned area. Some organisms thrive in edge communities because they gain resources from both adjacent areas. The ruffed grouse (Bonasa umbellus) is a bird that needs forest habitat for nesting, winter food, and shelter, but it also needs forest openings with dense shrubs and herbs for summer food. Ecosystems in which edges arise from human alterations often have reduced biodiversity and a preponderance of edge-adapted species. For example, white-tailed deer thrive in edge habitats, where they can browse on woody shrubs; deer populations often expand when forests are logged and more edges are generated. The brown-headed cowbird (Molothrus ater) is an edge-adapted species that lays its eggs in the nests of other birds, often migratory songbirds. Cowbirds need forests, where they can parasitize the nests of other birds, and open fields, where they forage on seeds and insects. Consequently, their populations are growing where forests are being cut and fragmented, creating more edge habitat and open land. Increasing cowbird parasitism and habitat loss are correlated with declining populations of several of the cowbird's host species.

Water Cycle

from the book pg. 907, however, part mentioned in slides is highlighted in purple: 1. Biological importance Water is essential to all organisms, and its availability influences the rates of ecosystem processes, particularly primary production and decomposition in terrestrial ecosystems. 2. Forms available to life All organisms are capable of exchanging water directly with their environment. Liquid water is the primary physical phase in which water is used, though some organisms can harvest water vapor. Freezing of soil water can limit water availability to terrestrial plants. 3. Reservoirs The oceans contain 97% of the water in the biosphere (aka oceans). Approximately 2% is bound in glaciers and polar ice caps, and the remaining 1% is in lakes, rivers, and groundwater, with a negligible amount in the atmosphere. 4. Key processes The main processes driving the water cycle are evaporation of liquid water by solar energy, condensation of water vapor into clouds, and precipitation. Transpiration by terrestrial plants also moves large volumes of water into the atmosphere. Surface and groundwater flow can return water to the oceans, completing the water cycle. from slides: Water moves by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater transpiration definition from Quizlet: Evaporation and loss of water from the leaves of a plant

Energy Partitioning Within a Link of the Food Chain

from the book: Production efficiency - is the percentage of energy stored in assimilated food that is used for growth and reproduction, not respiration (dr. sata said we don't need to know any of the specific numbers but to know the relative change) • Birds and mammals have low production efficiencies (about 1-3%) due to the high cost of endothermy remember endothermy: Humans and other mammals, as well as birds, are endothermic, meaning that they are warmed mostly by heat generated by metabolism; generate heat from the inside • Fish have production efficiencies around 10% (from dr. sata - fish maintain a temperature similar to their surroundings) • Insects and microorganisms have efficiencies of 40% or more • Trophic efficiency is the percentage of production transferred from one trophic level to the next, on average about 10% • Trophic efficiencies take energy stored in unconsumed biomass at lower trophic levels as well as energy lost to feces and respiration from book pg. 904 on trophic efficiency: Trophic efficiencies must always be less than production efficiencies because they take into account not only the energy contained in feces and the energy lost through respiration, but also the energy converted to new biomass in a lower trophic level but not consumed by the next trophic level. Trophic efficiencies range from roughly 5% to 20% in different ecosystems, but on average are only about 10%. In other words, 90% of the energy available at one trophic level typically is not transferred to the next. This loss is multiplied over the length of a food chain. If 10% of available energy is transferred from primary producers to primary consumers, such as caterpillars, and 10% of that energy is transferred to secondary consumers (carnivores), then only 1% of net primary production is available to secondary consumers (10% of 10%).

Global Energy Flow (just understand the flow, don' tneed ot memroize)

from the website on the slide he linked: Reflection off ice and snow is more typically in the low 70%'s. Absorption by water without ice and snow depends greatly on the sun angle: 94% when the sun is overhead, but much less at the angle becomes more glancing. from dr. sata: energy radiation comes in, some is absorbed by the atmosphere, some is absorbed by the surface and some is reflected back. whatever is absorbed, evapotranspirtion will release some of that heat. then thermoradiation happens then (too lazy to finish lol)

Water Usage in Agriculture

from website linked on slide: In most regions of the world, over 70 percent of freshwater is used for agriculture. By 2050, feeding a planet of 9 billion people will require an estimated 50 percent increase in agricultural production and a 15 percent increase in water withdrawals.

Is biodiversity good for your health?

higher pathogen diversity results in lower infection rates (see graphs). variation provides survival in both the host and pathogen

How Large Bodies of Water and Mountains Affect Climate

large bodies of water such as lakes, oceans, rivers, etc. from pic: 1) Cool air flows inland from the water, moderating temperatures near the shore. 2) Air that encounters mountains flows upward, cools at higher altitudes, and releases water as rain and snow. 3) Less moisture is left in the air reaching the leeward side, which therefore has little precipitation. This rain shadow can create a desert on the back side of the mountain range. from dr. sata: moist air comes in from the ocean flowing inland and becomes rain. the windward side gets most rian, leeward side doesn't get as much rain bc cloud doesn't move on this side??

Water Use in Animal Husbandry

much of the Water Used in Animal Husbandry is on beef and cattle and in livestock and in the midwest, Carolinas, west regions where is the water they use coming from? from freshwater lakes, rivers, ponds, and from the ground

Where are the westerlies located?

near the north and south pole

Zonation in a Lake

• Aquatic biomes show less latitudinal variation than terrestrial biomes • The largest marine biome is made of oceans, which cover about 75% of Earth's surface and have an enormous impact on the biosphere • Oceans temperatures impact global climate and wind patterns and moderate climate of nearby land from book pg. 857: Unlike terrestrial biomes, aquatic biomes are characterized primarily by their physical and chemical environment. For example, marine biomes generally have salt concentrations that average 3%, whereas freshwater biomes such as lakes and streams typically have a salt concentration of less than 0.1%. Another important feature of many aquatic biomes is that they are divided into vertical and horizontal zones, as illustrated for a lake in Figure 40.10. Light is absorbed by water and by photosynthetic organisms, so its intensity decreases rapidly with depth. The upper photic zone is the region where there is sufficient light for photosynthesis, while the lower aphotic zone is the region where little light penetrates. These two zones together make up the pelagic zone. At the bottom of these zones, deep or shallow, is the benthic zone, which consists of organic and inorganic sediments and is occupied by communities of organisms called the benthos. In a lake, aquatic biomes can be divided horizontally into the littoral zone, waters close to shore that are shallow enough for rooted plants, and the limnetic zone, waters farther from shore that are too deep to support plants with roots. Aquatic biomes show far less latitudinal variation than terrestrial biomes, with all types found across the globe (Figure 40.11). The oceans make up the largest marine biome, covering about 75% of Earth's surface. Because of their vast size, they greatly impact the biosphere. Water evaporated from the oceans provides most of the planet's rainfall. Marine algae and photosynthetic bacteria supply much of the world's oxygen and consume large amounts of atmospheric carbon dioxide. Ocean temperatures have a major effect on global climate and wind patterns (see Figure 40.3), and along with large lakes, oceans tend to moderate the climate of nearby land. pic description: A lake environment is generally classified on the basis of three physical criteria: light penetration (photic and aphotic zones), distance from shore and water depth (littoral and limnetic zones), and whether the environment is open water (pelagic zone) or lake bottom (benthic zone).

Effective Population Size

• Effective population size (Ne) is estimated by (See pic for formula) where Nf and Nm are, respectively, the number of females and the number of males that breed successfully • Ne is always a fraction of the total population • Viable population size was estimated for grizzly bears in and around Yellowstone National Park • Given suitable habitat, 70-90 bears would have a 95% chance of surviving for 100 years; 100 bears would have 95% chance of surviving for 200 years • The Yellowstone population includes about 400 bears, but the effective population size is about 125

Energy, Mass, and Trophic Levels (see pic)

• Energy and nutrients pass from primary producers (autotrophs) to primary consumers (herbivores) to secondary consumers (carnivores) to tertiary consumers (carnivores [and omnivores] that feed on other carnivores) • Detritivores, or decomposers, are consumers that derive their energy from detritus, nonliving organic matter • Prokaryotes and fungi are important detritivores • Decomposition connects all trophic levels

Exponential Growth in the African Elephant Population of Kruger National Park, South Africa

• Exponential growth assumes unlimited resources; in nature, resources are usually limited • A more realistic model limits growth by incorporating carrying capacity • Carrying capacity (K) is the maximum population size a particular environment can support given its abundance of limiting resources (food availability, water availability and other biotic factors that limit the population size)

Effect of Global Warming on Humans

• Food shortage • Water resources • Heating and cooling cost • Extreme weather events • Diseases • Heat wave causing deaths • Loss of habitable area due to ocean levels rising.

Effect of Global Warming on Plants and Agriculture

• Increased droughts • Expanded coverage by tropical plants and weeds • Reduced crop yields • Increasing food insecurity • Increased salinity • Reduced water availability • Reduced Arable Land

Effect of Population Growth on Resources

• Land use and housing: Construction resources - wood, cement and other materials. • Resource utilization: Water, electricity and fossil fuels. Residential and industrial needs. • Transportation: Personal and public use vehicles • Employment: Buildings and resources for construction and maintenance • Food consumption: Plant and animal food production and distribution. • Waste management: solid, liquid and hazardous materials. • Cumulative effect on the environment: Impact of the above practices are interconnected and complex to affect the overall environmental quality

Nutrient Limitation and CO2 Fixation

• More than light, nutrients limit primary production in oceans and lakes • A limiting nutrient is the element that must be added for production to increase in an area • The nutrients that most often limit marine production are nitrogen and phosphorus. from book pg. 900: Concentrations of these nutrients are typically low in the photic zone because they are rapidly taken up by phytoplankton and because detritus tends to sink. from dr. sata: carbon, hydrogen, and oxygen are present in all molecules whereas nitrogen is only present in nucleic acids and protein. phosphate is present in phospholipids and nucleic acids. all these molecules are necessary for a living organism. so if a nutrient is limiting phosphorus or potassium or iron, etc. the productivity will go down. • For example, nitrogen limits phytoplankton growth off the south shore of Long Island, New York

Ecosystems Vary Greatly in NPP

• Most productive: tropical rain forests, estuaries, and coral reefs • Marine ecosystems are relatively unproductive but contribute much to global net primary production because of their size • Terrestrial ecosystems: water availability and temperature definition from Quizlet: An ecosystem that is found on land (ex. forests, meadows, deserts) • Aquatic ecosystems: nutrient availability definition from Quizlet: An ecosystem located in a body of water from dr. sata temp, water, energy are 3 aspects of idk???? maybe precipitation pic description: This map is based on satellite-collected data, such as amount of sunlight absorbed by vegetation. Note that tropical land areas have the highest rates of production (yellow to red on the map).

Net Ecosystem Productivity (NEP)

• Net Ecosystem Productivity is a measure of the total biomass accumulation during a given period • NEP is gross primary production minus ecosystem respiration (Reco), which is the total respiration of all organisms (producers and consumers) in an ecosystem NEP = GPP - Reco NEP is estimated by measuring the net flux of CO2 in an ecosystem: • Photosynthesis: CO2 enters ecosystem • Respiration: CO2 released from ecosystem • Ecosystem is a carbon sink when NEP > 0 or GPP > Reco • Ecosystem is a carbon source when NEP < 0 or GPP < Reco • NEP is affected by light, nutrients, water and CO2 availability

Biological Treasures

• Scientists have named and described about 1.8 million species; estimates for the number of species on Earth range from 5 million to 100 million • The tropics have some of the greatest concentrations of species, but tropical habitats are being rapidly destroyed • Many unique species are being pushed to the brink of extinction due to human activities