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39 Cards in this Set
- Front
- Back
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What is evolution?
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A change in gene frequency over time.
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What is natural Selection?
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A process which passes favorable traits to the next generations. Often these traits are best suited to the organisms specific environment.
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What are the three types of natural selection?
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Directional
Stabilizing Disruptive |
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What is speciation?
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The process by which new species come into being.
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what is allopatric speciation?
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A single interbreeding population, is separated by a barrier. They evolve separately and when they are reunited they cannot interbreed.
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What is sympatric speciation?
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Individual live in the same area, some form of reproductive isolation occurs, temporal or spatial.
Ex. Canada goose, migratory v. resident. |
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Adaptive radiation
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A burst of evolution, genrally from a single species, that leads to occupation of available niches.
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What is a niche?
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an organisms functional role in the community.
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Habitat
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the biotic and abiotic elements in an area in which an organism lives.
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Biodiversity
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The sum of an area's organisms, and includes the diversity of , species-genes, and ecosystems.
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Mass extinction
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where 50-95% of the earths species are wiped out
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Exponential growth
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there are no constraining factors to limit population growth.
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logistical growth
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Has initial quick growth but then levels out, because of limiting factors.
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limiting factors
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Resources, predators, and disease.
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Type 1 survivorship curve
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Survival rates are high when organisms are young and decrease sharply when organisms are old - humans
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Type 2 survivorship curve
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Survival rates and equivalent regardless of an organisms age.
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Type 3 Survivorship curve
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Most mortality takes place as young ages and survival rates and greater at old ages.
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r-selected species
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Many offspring
Fast growing No parental care quick to meet sexual maturity |
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K-selected speices
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Few offspring
slow growing parental care slow to reach sexual maturity |
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community
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all the organisms existing in an area at a particular time.
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Exploitation
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one species benefits, other negative impact
Herbivory Predation Parasites |
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Mutualism
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Both benefit from interaction
Humming bird - flower |
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Amenalism
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one harmed, other neutral
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Commensalism
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one positive, other neutral
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Facilitative mutualism
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species benefits from interaction, but not solely dependent
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Obligate Mutualism
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species completely rely on one another
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competition
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when multiple individual seek the same limited resource - has negative impact on competing individuals.
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Interspecific competition
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betrween 2 or more species - can alter community composition
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Intraspecific competition
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within a species-compete for resources
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competitive exclusion
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one species completely excludes the other from a resource.
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species coexistence
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species who require the same resource, but can reach a stable population equlibrium.
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resource partitioning
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species specialize indifferent ways of exploiting a resource
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Autotrophs
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generate their own food, from sun (photosynthesis)
also known as producers |
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detritivores and decomposers
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eat nonliving organic material
recycle nutrients |
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primary consumers
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consume producers, in the second trophic level
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secondary consumers
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prey on primary consumers, on the third trophic level
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Tertiary consumers
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highest trophic level, prey on lower trophic levels.
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keystone species
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speciesimpacts that have especially great impacts on other community members and on the community's identity.
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ecosystem engineers
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act as a keystone species due to impact on community, DRAMATICALLY alters the community structure by changing the habitat.
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