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| when individuals of a different species compete for a resource that limits their growth and survival |
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| one species kills and eats the other |
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| an organism eats parts of a plant or alga |
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| individuals of two or more species live in direct and intimate contact with one another |
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| fundamental and realized niche |
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| fundamental niche is the niche that a species could potentially occupy while a realized niche is the niche that the species actually occupies, often due to restrictions caused by the niches of other species |
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| coloration that warns predators that a species is posionous |
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when a harmless species mimicks a harmful one
ex- larva that looks like a snake |
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| when a harmless species mimicks another harmless species. the more unpalatable prey, the sooner predators learn to aviod such markings |
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| when a parasite gets its nutrients from a host, harming it in the process |
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| when both species benefit from an interaction. in obligate on species has lost the ability to live without the other. in faculative, both species can survive alone |
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| an interaction that benefits one species but the other is unaffected. often involves one species gaining food inadvertently exposed by the other. |
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| parastites that live within the host |
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| parasites that live on the outside of a host |
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| part of species diversity, refers to the number of different species in the community |
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part of species diversity, refers to the proportion each species represents of all the individuals in a community.
basis of shannon diversity index:
= -(PalnPa + PblnPb+ ...) |
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| transfer of food energy up through trophic levels |
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| linked together food chains that illustrate the trophic relationships of a communtity |
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when ecological succession occurs in a virtually lifeless are where no soil has yet formed
ex- areas uncovered by receeding glacers |
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ecological succesion that occurs when an existing community has been cleared by some disturbance that leaves the soil intact
ex- forest fires |
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| define an ecological niche and explain he competitive exclusion principle in terms of the niche concet |
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| a niche is the a species use of abiotic and biotic resources in its ennvironment. two species cannot coexist permenently in a communiity if their niches are identical. resource partitioning is the differentiation of niches that enables similar species to coexist in a community and character displacement |
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| explain how dominate and keystone species exert stron control on community structure |
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dominant species are the most abundant collectively, and thus exert control over the occurance and distribution of other species because they are competitively supperior in exploiting limited resouces or are the most successful at avoiding predition or the impact of disease. ex- maples in the NE US have major impact on abiotic resource ability and environmental factors such as shade, so they control the diversity and abundence of their community
Keystone species are not abundent in a community, but they have strong control over their communities because of their pivitol niches. ex- sea otters |
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| distinguish between bottom up and top down community organization |
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Definition
there is a unidirectional infulence from lower to higher tropic levels in botom up communities. to change the structure of these communities, you need to alter the biomass of at the lower trophic levels. adding or removing predators does not affect the lower levels. ex- more nutrients = more plants= more rabbits
in top down communities, preditation mainly controls the community organization. predators limit herbivors, which allows more plants to grow. addition or removal of predators affects all lower levels |
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| describe and explain the intermediate disturbance hypothesis |
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| this hypothesis states that moderate levels or disturbance foster greater species diversity. high disturbance levels reduce diversity by exceeding the tolerances of many species or occuring so ofthen that slow growing species cant keep up and are exluded. low dieturbance levels also lower diversity because the competitively dominate species exlude the less competitive ones. |
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| explain why species richness declines along an equatorial polar gradiant |
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| species richness is highest at the tropics because these communities are older and polar communites have "started over" after glaciations. the growing season in the tropics is also longer, so there are more speciation events. the warm climate also provides more solar energy and water. a good way to measure this is through evapotranspiration. high evapotranspiration correlates to high species richness. |
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| define zoonotic pathogens and explain, with an example, how they may be controled |
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| these pathogens are transfered to humans from other speices through direct contact with the infected species or a vector. for example, rabies in animals. the brittish isles are rabies free, and in order to maintain these they quaritine all potential carriers upon enterance to the country, and insure that all members of the community are vaccinated. |
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