Ecology Exam 1
1. Provide 2 benefits of dispersal on populations and 2 negative consequences on populations.
. Benefits-possibly finding greater area for resources, expanding population, finding mates with different genes a. Disadvantages-many offspring die, unable to colonize some areas due to fundamental niche, more likely to get eaten, could survive but not as well as in other area
What is a fundamental evolutionary implication of the large amounts of genetic variation commonly documented in natural populations?
. One of the major implications of widespread genetic variation in natural populations is that there is great potential for evolution by natural selection in most natural populations.
population
.A group of individuals of a single species inhabi±ng a de²ned area
The earth wobbles a bit on its axis form 22.1 to 24.5 degrees, with a full wobble taking about 40,000 years. We are currently at 23.4 degrees and moving toward less ±lt. What do you think the impact on global climate would be when the ±lt is at the minimum of 22.1 degrees?
.At reduced ±lt, average temperature would drop and polar ice caps would grow
Describe what ecologists mean by dispersal, then list and briefly describe one advantage a species with a long dispersal distance would have and one disadvantage.
1. . Dispersal is the act of a species moving randomly to a new location. One advantage a species with a long dispersal distance would have would be that it is less likely to fall victim to extinction because they are not just located in one remote area. One disadvantage would be that it would get too far away from where it lies because it never found any resources to support it. One example is source/sink dispersal in butterflies.
Anthropogenic climate change is more rapid than changes driven by Milankovitch cycles. Describe three potential responses of a species facing a changing climate. Use bullets to list them. Then, briefly explain how the species responses would be different for fast anthropogenic change or slow Milankovitch cycle driven changes, and what factors could limit the species' capacity for responding to the change
1. Adaptation: possible for Milankovitch change, but may not be for anthropogenic due to its increased rate. Individuals don't have enough time (generations) to successfully evolve. Migration: possible for both types of climate change. Of course some species will be limited due to decreased range/mobility. Extinction: more likely to be caused by anthropogenic than Milankovitch because anthropogenic changes occur more rapidly allowing for less time to adapt which could potentially result in extinction.
Species that exist today have adapted to changing climates in their past. What could limit the capacity of species to adapt to anthropogenic climate change?
1. Anthropogenic changes are occurring rapidly, leaving some long lived organisms with only a few generations to adapt. Not having the right alleles in the gene pool or a lack of genetic variation within the population
Where is Arkansas on a scatter plot of biomes with rainfall and temperature as x- and y-axes. Add in other important biomes, such as tropical rainforest, tundra, desert, and grasslands? What other factors besides climate impact whether a site is forested or in grassland in Arkansas?1.
1. Average Temp. = 15 C, rainfall around 140 cm annually (grassland/temperate forest). Human involvement and type of soil impact also impact whether a site is forested or in a grassland.
I have mentioned Darwin's emphasis on the struggle to survive due to unsuitable abiotic conditions or competition or predation. What evidence did he have that convinced him that all species struggle to survive?
1. Because he realized that all species have too many offspring to survive, any species that did not suffer great mortality of offspring would quickly overpopulate the whole planet.
What kinds of interactions within an animal population lead to clumped distributions? What kinds of interactions foster a regular distribution? What kinds of interactions would you expect to find within a population distributed in a random distribution?
1. Clumpedpatchy & social, Regularterritorial, Randomnon-aggressive
Add to your figure above using a dashed line indicating a new fundamental niche with higher temperature tolerances. Explain below how the species changed its fundamental niche.
1. Evolution, it may have moved to a new location or a small population of them may have been accidentally transported by humans, and a small portion of that population was able to adapt and start a population with a modified niche.
What characteristics of an organism increases the likelihood that it will expand it's range under the current rapid anthropogenic changes
1. Having many offspring and having a short generation time
Imagine two species occupying slightly different habitats, for example two different plant species, one growing in an area with soil that was acidic and the other in more basic soils. How could you determine if they were strong interspecfic competitors?
1. If you grew both species in pots with either acid soils or basic soils by themselves and together, you could compare their biomass under intraspecific competition and under interspecific competition. If species A was capable of growing in basic soil by itself, but had significantly reduced biomass when grown with B in basic soil, you could conclude it was interspecific competition that prevented it from being found on basic soils in the field.
We focused much of our discussion of biomes on their latitudinal distribution. The reasonably predictable relationship among latitude and temperature and precipitation provides a link between latitude and biomes. What other geographic variable might affect the distribution of temperature and precipitation and biomes?
1. Other major factors are altitude, distance from the oceans (the interior of large continents are often dry), and the presence of mountains which can force precipitation in rising air masses and form a "rain shadow" in the leeward (downwind) side.
Why might a species, such as the Eurasian collared dove, be less threatened by rapid climate change than hemlock or maple trees?
1. The documented dispersal rate of Eurasian collared doves is much higher than that shown by hemlock and maple trees.
What are the major aquatic biomes? What physical and chemical characteristics are used to distinguish these biomes from each other? What are two aquatic biomes in Arkansas and how have they changed over the past 200 years?
1. The major aquatic biomes can be divided into two categories: Marine and Freshwater. Marine biomes include open-ocean, shallow-ocean (estuary, mangrove forest, coral reefs, and kelp forests). Freshwater biomes include rivers, streams, lakes, wetlands, and groundwater. Physical characteristics that distinguish between these habitats include water movement, water temperature, water depth, and light penetration. Chemical characteristics that distinguish between these habitats include salinity (types of salts: NaCl, Mg, Ca), dissolved oxygen (daily min/max), and nutrients (nitrate, ammonium, and phosphorous). Two aquatic biomes in Arkansas include wetlands and rivers. The wetlands have changed over the past 200 years in the fact that nearly 89% have been destroyed for farming since 1870. Rivers have changed their courses due to flooding, and have been dammed up. The Arkansas Game and Fish Commission regulate the species in these rivers.
how may a species respond to climate change
A species may shift its geographical distribution with climate change; it may adapt to the new environmental conditions; or do both. Large and rapid climate change may lead to extinction.
Explain how a species adapts to changes in its environment through the process of natural selection, making sure to specifically point out the ecological and evolutionary parts of natural selection. Use a specific example to help you explain
1. The soapberry bugs exhibited the process of natural selection. The original plant that they penetrated with their beaks to obtain nutrients had a bigger radius than the plants that were introduced later on. The soapberry bugs that fed on the original plant had longer beaks to reach the nutrients, while the bugs that fed on the newly introduced plants had shorter beaks that correlated with the smaller radius. This proves that a species will adapt through only the individuals that are best suited for the conditions. Therefore, their genes give them that advantage. The ecological part of this is the interactions of the plant while the evolutionary part is the loss of the less-surviving gene, therefor allowing the ones that are best suited to survive.
Both Africanized honeybees and Eurasian Collared Doves have moved northward since they were introduced. Which best explains why?
1. They disperse away from their birth site in random directions, but have a few individuals that can fly considerable distances. Individuals of both species simply survive in habitats where they find their fundamental niche, and for both species those sites have been north of their original sites of introduction.
State one testable hypothesis that could be asked about how a human's microbiome composition could influence their health. What level of ecological hierarchy is your hypothesis focused on? Clearly state the dependent and independent variables.
1. We could take a sample from many individuals and see if there is a reoccurring trend when the composition was compared to certain testable health conditions (blood pressure cholesterol, diabetes). Hypothesis: An individual's microbiome correlates with whether they have high cholesterol because of the interactions with our gut. Independent: microbiome content, Dependent: cholesterol level.
aquatic habitats
97% oceans 2% ice caps and glaciers <1% in lakes, rivers, wetlands, groundwater Rainfall patterns generated by uneven solar heating Seasonal change in photosynthesis in the ocean Due to the earth's tilt, the shift of the solar equator causes more photosynthesis (closer tilt=more)
Temperature is important for the evolution and ecology of organisms. How would a species change its fundamental niche to tolerate higher temperatures (assume the species does successfully change its fundamental niche)?
A fundamental niche is the entire set of living conditions a species or organisms can undergo to survive and reproduce. There are various ways a species change to tolerate relatively high temperatures, but the most important one of them being rapid adaptation though natural selection.
An ecosystem is de²ned as
All of the organisms that live in an area and the physical environment with which they interact1
Why do those regions, whether tropical, desert, or temperate, which include high mountains tend to be the most biologically diverse?
Along their slopes, high mountains include a broad range of environments that can support a high diversity of organisms.
What is needed for a species to change its fundamental niche
An evolutionary change in the species
Species have always adapted to changing climates in the past. What could limit the capacity of species to adapt to anthropogenic climate change?
Anthropogenic changes occur rapidly, giving less ±me for natural selec±on to change allele frequencies
If the adults of aquatic stream insects did not specifically disperse by flying upstream, what would happen?
Because the immature stages tend to get swept downstream, if the adults did not disperse by flying upstream, the whole population would move downstream.
levels of ecological organization
Biosphere, region, landscape, ecosystem, community, interactions, population, individuals
According to the river continuum, the main energy source for small head streams is
CPOM (coarse particulate organic material)
angle of incidence
Changes through seasons because the earth is tilted on its axis Solar equator because of tilt, hits perpendicular at warmest points and diffuses at non-perpendicular points Climate changes geographically across the planet Seasonal changes in climate Transitions between ice ages and interglacial periods Vertical lines-longitude; horizontal lines-latitude; goes up to 90 degrees
What are the major abiotic variables that control biota in aquatic habitats?
Chemical environment Salinity-salts (sodium chloride, magnesium and calcium) Dissolved oxygen-daily min-max Nutrients (nitrate, ammonium, phosphorus) Physical environment Water movement-lentic (lentic (still), lotic (flowing) Temperature-mean annual or min-max Water depth-mean annual or min-max Light-penetration (change at depth) Nutrients at the bottom get mixed up in the ocean by more shallow water depth and light at more shallow temperatures
evolution
Darwin-natural selection Variation between natural species, didn't know what source of variation was Rapid increase of naturalized animals and plants in a new area-ex. Cats Do not write "survival of the fittest" Effects of climate fitness-individuals ability to survive and reproduce; environment specific and depends on both a/biotic factors evolution of optimal fitness is constrained by existing variation, trade offs, and other factors the process whereby organisms better adapted to their environment tend to survive and produce more offspring most organisms have anatomical and physiological traits that tend to increase their fitness for a particular environment natsel has favored structures whose shape and composition contribute to their ecological function
3. Describe the relationship between dispersal and range expansion.
Dispersion is the movement of offspring away from its birth place. Range Expansion is the act of expanding a species range of living for reasons such as greater resources.
warm blooded animals
Don't use as much energy Don't have to worry about overheating
Why is so much of our data on dispersal rates focused on exotic species introductions?
Easier because it is a starting point for the species; we assume all other members of the species disperse this way
Be able to describe an experiment testing an ecosystem, population, and community-level research question. Can you identify the dependent and independent variables
Ecosystem: How does fire affect nutrient availability in grassland ecosystems? Dependent: amount of nutrients Independent: fire // Population: What factors control zebra populations? Dependent: zebra count Independent: factors affecting them // Community: What factors influence the number of large mammal species living together in African grasslands? Dependent: number of large mammal species Independent: factors affecting them
What limits energy acquisition in terrestrial biomes?
Energy acquisition is limited in terrestrial biomes by the location of the biome and the latitude in correlation with the sun.
rate of dispersal and pop expansion varies
Environmental conditions Resources Climate Life history Size Lifespan Growth rate Fecundity
pop growth
Exponential
brown recluse spider
Fundamental niche determines potential geographic distribution
Aquatic invertebrates are different
Get carried downstream in the water Can see polarized light, cast a light on water that they can see far down the stream
pop distribution
Global or geographic scale Physiological tolerance to abiotic conditions Terrestrial-precipitation and temperature Aquatic-salinity, dissolved oxygen, temperature, water movement, light Local scale-within its wider geographic distribution, individuals are denser in some areas Physiological tolerance to abiotic conditions Resource distribution Biotic interactions like competition or social interactions
What characteristics of an organism increases the likelihood that it will expand its range?
High reproductive rate, wide habitat tolerance, the capacity to disperse long distances, changing of food supply.
The earth wobbles a bit on its axis from 22.1 to 24.5 degrees, with a full wobble taking about 40,000 years. We are currently at 23.4 degrees and moving toward less ±lt. What do you think the impact on climate here in AR would be when the ±lt is at the minimum of 22.1 degrees?
I would be cooler in the summer and warmer in the winter.
How will organisms respond to environmental change?
Move How will movement of these trees over the last 20k years compare to the potential movement of brown recluse spiders in the next 100 years? Human movement
Temperature forest in the eastern US and AR was a cri±cal source of wood and logs during the early history of the US. What percent of the original eastern temperate forests have been cut down
Nearly 100%
rivers and streams
Nitrogen is most difficult nutrient for plants to get Fungi and bacteria can break down cellulose
What happens when the abiotic conditions change due to climate change?
Less available space that organisms can inhabit The whole population can die and go locally extinct Some individuals could survive due to a genetic trait and the population could adapt to the warmer conditions
why do organisms disperse
Life history characteristic Adaptation to increase probability some offspring will survive Organisms tend to move away from natal population at some specific point in their life, dangerous Propagation of the species-reproduction-when, how often, how many, etc.-account for many differences between species Advantage to dispersal-environments change, new places that could be found, expan Why would you want to make offspring that aren't like yourself? The environments change so what worked once might not work again Some organisms can do both (change/not change)-aphids-can clone themselves (all female) if plant is resourceful, will produce male/female with wings which leave to increase variation Eurasian collared doves-fledgelings disperse a few km-hundreds of km
What organisms are responsible for fixing carbon in aquatic biomes?
Many times, bacteria are the organisms that are responsible for carbon fixation. They are an example in the deep sea.
main aquatic biomes
Marine-open ocean, shallow ocean (estuary, mangrove forest, coral reef, kelp forest) Freshwater biomes-rivers, streams, lakes, wetlands, groundwater
Where do most heterotrophic organisms get their energy in headwater streams? How does energy acquisition change as you go downstream? How would you expect energy acquisition to change following the removal of trees and planting of corn along the stream bank?
Most heterotrophic organisms get their energy in the form of leaves and other plant parts in headwater streams. As you go downstream, the energy levels tend to decrease. If trees are removed and corn is planted along the stream bank, I would expect oxygen levels to decrease since the tree leaves will be landing some place else.
What are the dominant autotrophic organisms and what are the dominant heterotrophic organisms?
Open ocean-nutrient limited; primary producers such as free-floating plankton Shallow areas near land-Attached micro algae such as kelp, nutrient runoff from land Rocky shorelines-mollusks, starfish, mussels
Why is a primary production different in a desert compared to a rainforest?
Primary production-made by plants Secondary production-made by animals Proximity to equator and water source (resources)
dispersal of organisms
Random Can be rapid Can increase or decrease local populations
Why is rapid, human induced environmental change a threat to natural populations?
Rapid, human-caused environmental change can outpace a population's capacity to adapt to the change through a process such as directional selection.
How did the studies of Scott Carroll and his colleagues demonstrate rapid evolutionary adaptation to introduced soapberry plants? What advantages do a group of organisms such as soapberry bugs offer to researchers studying natural selection compared to larger organisms such as Chihuahua spruce?
Scott Carroll and his colleagues demonstrated rapid evolutionary adaptation to introduced soapberry plants when they demonstrated that the various populations of soapberry bugs retain their normal beak length when reared on alternative host plants. Because they are smaller and have much shorter generation times, soapberry bugs are much more convenient for experimental studies compared to larger organisms such as Chihuahua pines and chuckwalla lizards.
Ecologists who have used clear plastic sheets coated with adhesive to trap the adults of aquatic insects flying over rivers have found that the side of the sheets facing downstream generally traps more of the flying adults than the upstream-facing side. Explain.
Since, according to Müller's colonization cycle, stream insects need to compensate for downstream movements during drift, the predominant direction of flight by reproductive adult stream insects should be upstream.
How are small streams connected to the surrounding terrestrial ecosystem?
Small stream are connected to the surrounding terrestrial ecosystem by the riparian zone.
Earth's axial tilt and spherial shape explain spatial and temporal variation in light energy
Spatial and temporal differences in light energy on the earth describe patterns in vegetation and precipitation Variation in axial tilt (milanchovich cycles) force periods of ice ages Changes in atmospheric concentrations of greenhouse gases act as additional forcing factors
population variation
Spatial variation Distribution-local to global scales-size, shape, and location of the area it occupies Dispersal ability Population dispersion Density-number of individuals per unit area Abundance-total number of individuals or biomass of a species in a specified area Variation over time Dynamics or change in numbers over time Birth and death rates
Outline Rabinowitz's classification of rarity, which she based on size of geographic range, breadth of habitat tolerance, and population size. In her scheme, which combination of attributes makes a species least vulnerable to extinction? Which combination makes a species the most vulnerable?
Species that have an extensive geographic range, broad habitat tolerances, and large local populations are the least vulnerable to extinction, while those with restricted geographic range, narrow habitat tolerance, and small local populations are the most vulnerable.
Why does temperature vary on a global scale?
Spherical earth More oblique rays at higher latitudes latitude/longitude Temperature and energy available to power ecosystems are both responding to the more diffuse light at higher latitudes Energy decreases if you move away from the equator
killer africanized bees
Stores male sperm for the rest of her life, establishes a nest Intense colony-will sting as many times as possible Did queens show a preference to move north? No, because they don't survive the winter well so it's not really in their fundamental niche. They send babies out in every direction to cover every possibility. In general, it's most adaptive to go in a random direction to find all possible sites that could be colonized. Price is a lot of offspring die.
Which two biomes are here in Arkansas?
Temperate forest and Temperate grassland
What is the main diFerence you see between temperate forests and temperate grasslands?
Temperate grasslands have less rainfall
What are major terrestrial biomes in Arkansas and how have they changed over the past 200 years? Is it still appropriate to classify them as biomes determined by potential vegetation type?
The major terrestrial biomes in Arkansas are temperate forests and temperate grassland. They have been converted to agriculture over the past 200 years.
Which of the responses below best describes why seasons change through the year here in AR.
The angle that solar rays hit the earth here in AR changes through the year
. What limits energy acquisition in aquatic biomes?
The depth of the water can limit energy acquisition in aquatic biomes. For instance, oceans will have much less overall energy from the sun than a stream would,, because the sun's rays cannot reach the very bottom of the ocean.
Explain what the dimensions represent in Hutchinson's niche concept and why he used 'n' dimensions. Draw a two dimensional fundamental niche for the brown recluse spider.
The dimensions represent certain ranges of environmental factors that a certain species can survive in. He used 'n' because there can be multiple dimensions.
Why might a species, such as the Eurasian collared dove, be less threatened by rapid climate change than hemlock or maple trees?
The documented dispersal rate of Eurasian collared doves is much higher than that shown by hemlock and maple trees.
1. Review the distribution of water among the major reservoirs of the hydrologic cycle. What are the major sources of freshwater? Explain why according to some projections availability of freshwater may limit human population and activity.
The major sources of freshwater are groundwater, lakes, and rivers. A large amount of freshwater is also present as ice. Water shortages already affect large regions of the world and groundwater levels are dropping in many regions. Even where water remains plentiful, pollution is reducing water quality.
According to the river continuum model, the organisms inhabiting headwater streams in temperate forest regions depend mainly upon organic material coming into the stream from the surrounding forests. According to the model, photosynthesis within the stream is only important in the downstream reaches of these stream systems Explain. How would you go about testing the predictions of the river continuum model?
The most direct way to test these predictions would be to study the relative contributions of litterfall from streamside forests and photosynthesis within the stream to the total energy budget of the stream.
Use what you know about atmospheric circulation and seasonal changes in the sun's orientation to earth to explain the highly seasonal rainfall in the tropical dry forest and tropical savanna biomes. (Hint: Why does the rainy season in these biomes come during the warmer months?
The seasonal rainfall of these biomes is produced by shifts in the latitude at which the sun is directly overhead. Figure 2.4a, which shows the sun directly overhead at the equator, which generates storms through the processes of evaporation, condensation and precipitation of water, is really a snapshot of a dynamic system. The latitude at which the sun is directly overhead, which is sometimes called the "solar equator", and acting as a generator of tropical storms shifts between 23.5° N and 23.5° S. The wet season comes during the warmer time of the year when the sun is more nearly overhead. The dry season comes when the solar input is less direct (sun's angle is more oblique).
Why does the annual rainy season in regions near 23 degreees N latitude begin in June?
The sun is directly overhead at 23.5° N latitude on June 21, the beginning of summer in the Northern Hemisphere, which results in cloud formation and precipitation at that latitude.
book excerpt
The wolves in "Wolves of Yellowstone," after being reintroduced to the environment and ecosystem there, had a profound impact on the other animals living there, as illustrated in the story. Each animal seemed to change their course of action and direction due to the wolves' presence. Just as with this situation, humans have a profound impact on our microbiome and vice versa, as discussed in The American Scholar excerpt. The microbes have a large impact on so many aspects of human life and bodily functions, such as digestion, immune function, and even behavior. Just as the gray wolf in the excerpt had distinct markings from each other wolf, the microbiome of the human body is diverse. The microbiome article even specifically mentions a connection to wolves as a comparison because of the influence certain microbes can have on others in the body. While not mentioned in the article, I know that the human body can also have an equal influence on the microbiome by the choices that we make such as diet or hygiene.
How would seasonality in temperature and precipitation be affected if earth's rotation on its axis were perpendicular to its plane of orbit about the sun?
There would be little or no seasonality in either temperature or precipitation.
How would seasonality in temperature and precipitation be affected if the earth's rotation on its axis were perpendicular to its plane of orbit around the sun?
There would be little or no seasonality in either temperature or precipitation.
Two anthropogenic impacts occurring now are climate change and introducing species to new geographic ranges. How do ecologists make predictions about where a newly introduced species may be able to establish?
They predict this by comparing the climates of where the species currently lives in relation to where it could potentially establish significant factors include temperature, rainfall, possible competitors (overlapping niches), amount of sunlight and urbanization.
Describe global patterns of atmospheric heating and circulation. What mechanisms produce high precipitation in the tropics? What mechanisms produce high precipitation at temperate latitudes? What mechanisms produce low precipitation in the tropics?
Use figure 2.4 and associated discussion as a guide. High precipitation in the tropics is produced by high rates of evaporation and subsequent condensation of water vapor in ascending air masses. The clouds formed in this way produce the heavy precipitation associated with the tropics. High precipitation at temperate latitudes is produced when warm moisture bearing subtropical air meets cold polar air, which forces condensation of the water vapor in the subtropical air mass. Many tropical environments experience drought during periods of El Niño (see chapter 23).
What happens when the conditions that define a species' niche hypervolume moves geographically because of climate change? a. Under historical slow rates of change b. Under recent rapid anthropogenic changes
Using the notes I took on Hutchinson's environmental factors affecting the niche of a species, I think that under both conditions, the environment is changing and this in turn changes the available environment which the species can inhabit, its fundamental niche. Under a slow change, the species would be able to evolve over time to the conditions it is presented with. In the conditions where change is fast, many of the organisms may die, although some may have the traits to endure the change and inhabit a new environment due to variation. In both cases, at least some of the organisms will die, but dispersal will also play an effect here because the conditions are causing the environment to move geographically. The organisms' dispersal will automatically trend in the direction of the move even though organisms start out in all directions because they will only be able to successfully inhabit the areas consistent with their fundamental niche.
How do populations of animals or plants adapt to abiotic conditions through natural selection?
Variation inapopulation(in heritabletraits) ALLTHE BUGS PRODUCEMOREOFFSPRINGTHANCANSURVIVE,SOAHUGE STRUGGLE FOR EXISTENCE Long beaked bugs more efficient (survive better) 1. If they adapt to new plant there would be less competition Shorter beakedbugsdiewhile longer beaksurvive
What are the consequences of greater energy input in equatorial zones
Warmer temperatures More energy available for metabolic function of living biomass in biomes More rainfall (figure 2.4) Warmer planet should generate more rainfall because of more evaporation Amount of energy from sun also affects patterns in preparation Dry air flowing over land absorbs moisture Moisture in ascending air condenses, forming clouds Arkansas-on line between temperate deciduous forest and woodland, shrubland, grassland
Why do areas in Arkansas get less solar energy/year than near the equator?
When the sun shines straight down like near the equator, there is less atmosphere between the earth and the sun to block the energy. In Arkansas, the sun in shining down at an angle, and it has to go through more of the blanket of the atmosphere before it touches the earth.
niche
a description of the environmental factors permitting a species to survive and reproduce Fundamental-physical conditions (abiotic)-defines the physical conditions under which a species might live in the absence of interactions with other species; determined by evolutionary interaction between environment and organism Hutchinsons definition-all abiotic factors that constrain where an organism is available to live n=number of environmental factors N-dimensional hypervolume Realized niche-actual niche of a species whose distribution is limited by biotic interactions such as competition, predation, disease, and parasitism
wetlands
abundance of nutrients, light limited at water surface, 89% of wetlands in AR have been destroyed and replaced with rice
malinkovitch cycles
arth's orbital changes drive the ice age cycles Procession-where pole is pointing Ice ages are determined by how much solar energy hits at the polar regions More tilt=more ice melted, warmer in summer Less tilted=sun hardly ever shines on polar regions, colder Tilt, procession, and eccentricity of orbit contribute to ice age cycles Carbon dioxide concentration (low) in atmosphere also influences ice age happening, so increasing postpones it We are about 1/2 -2 degrees warmer than 100 years ago (global warming)
For thousands of years, humans have bred domesticated plants and animals to produce and maintain desirable traits, such as large fruits. Darwin used which term to describe this:
artificial selection
Research suggests that the localized extinction of several species of land snails near Basal, Switzerland was due to
climatic warming
colonization cycle
dynamic view of stream populations in which upstream and downstream dispersal as well as reproduction have major influences on stream population
metapop
group of subpopulations living on patches connected by exchange of individuals among patches Ongoing dispersal can join numerous subpopulations to form a metapopulation
river continuum
in temperate regions, leaves and other plant parts are often the major source of energy available to the stream ecosystem
hink about the data you collected last week in lab about internode length in Japanese honeysuckle. You measured their length in mm. Which of the following are in the original units of mm?
mean,std,ste
zika virus
microcephaly in babies of affected mothers CDC Transmission by mosquitoes Follow distribution, which is dependent on dispersal Humans are a major player in how they are dispersed Density and abundance-a snapshot Dispersal and dispersion-change over time
lake
nutrient limited, deep, grinded out by glaciers
subpop
part of a larger population, with which it sustains a limited exchange of individuals through immigration and emigration
What dependent variable below would be part of community level study?
species per m2
According to Levins' principle of allocation, adaptation (higher fitness) to one environment results in reduced fitness in another environment
true