APES - Test Modules 10-14

ecological tolerance

also called fundamental niche, suite of abiotic and biotic conditions under which a species can survive, grow and reproduce

realized niche

exactly where the ideal ecological tolerance is located

geographic range

areas of world where a species lives

how do changing environmental conditions affect ecosystems?

they cause change in the distribution of species

what is an example of this?

• as climate change increases, many species will move upward in latitude to adjust

• some species are not as mobile, so they will die

mass extinction

when a large number of species goes extinct over a short period of time

sixth mass extinction

scientists believe we are experiencing a sixth global extinction with a rate of about 2 species per year

periodic disruption

occurs regularly

ex. day/night cycles

episodic disruption

occurs somewhat regularly

ex. rain patterns

random disruption

no regular occurrence

ex. tornado

resistance

measure of how much a disruption affects the energy and matter flows in an ecosystem

resillience

rate of which an ecosystem can return to original state after disruption

relationship between disruption duration and spatial extent of effects

direct

methods of measuring climate level of historic ages

• looking at air bubbles in ice

• looking at species of foraminifera in ocean sediment

method of measuring sea level throughout historic ages

fossils found in sediment

results of water level findings

during the Ice Age, there were large-scale sheets of ice and as those melted, water level increased

effect of large, rare disturbances

large habitat destruction

effects of intermediate level disturbances

intermediate disturbance hypothesis! these regions will have higher levels of species diversity

effects of seasonal disturbances

animal migration

island biogeography

study of how species are distributed + interacting on islands

species-area curve

as area of land increases, the number of species sustained increases

islands that are closer to continents . . .

have better species richness

islands with few species . . .

• have a high rate of colonization

• have a low rate of extinction

islands with many species . . .

• have a low rate of colonization

• have a high rate of extinction

larger islands have . . .

lower extinction rates because they can support larger populations

islands near to continents . . .

• have a higher rate of colonization

• have a higher rate of extinction

islands far from continents . . .

• have a lower rate of colonization

• have a lower rate of extinction

number of species ranking

1. large, near

2. large, far

3. small, near

4. small, far

rate of colonization ranking

1. small, near

2. small, far

3. large, near

4. large, far

rate of extinction ranking

1. small, near

2. small, far

3. large, near

4. large, far

artificial selection

breeding

natural selection

the environment determines which species survive and reproduce

Darwin’s rules for natural selection

1. variation in traits

2. traits are inherited

3. some traits provide advantage

who came up with natural selection?

Charles Darwin and Alfred Wallace

fitness

the ability to survive and reproduce

adaptation

a trait acquired over time by individuals that improve fitness

mutation

a random variation in DNA that improves genetic variation

gene flow

process by which individuals move from one species to another to alter the genetic composition of both

bottleneck effect

the rapid reduction in population of a species leads to less genetic diversity

founder effect

if a few individuals are separated from their population, they will produce genetic variation based on their traits alone

reasons for extinction

• condition change

• endemic reasons

• need for specific conditions to breed

• need for specific food sources

• small population

microevolution

evolution within a population

macroevolution

evolution that develops into a new family

allopatric speciation

1. a population is split off by a geological barrier

2. those two sections experience reproductive isolation

3. they become two different species

reproductive isolation

evolution so developed that interbreeding with the other species would not be possible

Bob Paine’s experiment

removed the starfish (highest predator) from a tide pool

Bob Paine’s results

the mussels overpopulated and destroyed the ecosystem

keystone species

a species that ha key influence on the strength of an ecosystem

Jim Estes experiment

observing kelp forests with and without the presence of otters

Jim Estes results

without the otters to eat sea urchins, the urchins overpopulated and ate the entire kelp forest

Jim Estes conclusion

keystone species affect both small and large aquatic ecosystems

Mary Power experiment

removing the large-mouthed bass from one side of the river

Mary Power results

The side without the bass was overpopulated by minnows and they ate everything

Mary Power conclusion

a keystone species’ effect can go beyond just population control

ex. in this case, the bass also provided a fear factor that makes the minnows too scared to eat so much and stay in one place

John Terbourgh experiment

he observed one of the Guri island with jaguars + army ants and one without

John Terbourgh results

without the jaguars and army ants, the other species overpopulated and ate all the vegetation

John Terbourgh conclusion

the keystone species theory also applies to terrestrial ecosystems

Tony Sinclair experiment

observed how the wildebeest population was increasing rapidly as a rebound after a disease outbreak and chose to leave them alone despite pleas from donors

Tony Sinclair results

eventually the wildebeest population plateaued, they also increased the tree population by preventing burning, which in turn allowed other species to flourish

Tony Sinclair conclusion

a species can be a keystone even if it is not a predator