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unit 4 biology
unit 4 ecosystems stability and change
Question | Answer |
---|---|
measurements of the number of individuals living in a defined space | population density |
how a population is spread in an area | population dispersion |
individuals gather into groups where resources are available (ex. fish) | clumped |
what affects population growth | births, deaths, migration, limiting factors |
population size increases dramatically over a relatively short period of time | exponential growth |
population begins with a period of slow growth followed by a period of exponential growth before leveling off at a stable size | logisitics growth |
competition, disease, and over crowding | density dependent |
natural disaster | density independent |
amount of organisms an ecosystem can support | carrying capacity |
what would happen if a carrying capacity exceeded | organisms die because lack of resources |
completely destroyed (ice age, mass volcanoes) | primary succession |
partly destroyed and can come back relatively soon (flood, fire) | secondary succession |
first species to occupy an area | pioneer species |
a specific place or role for an organism in an ecosystem | niche |
2 species cannot share the same niche in the same __________ | habitat |
causes species to divide resources | competition |
organisms feed on one another | predation |
the hunter | predator |
one who is getting eaten | prey |
a species that can change an ecosystem dramatically | keystone species |
when organisms from a relationship | symbiosis |
both species benefit | mutualistic |
one benefits and the other is not harmed or helped | commensalism |
one benefits, one harmed | parasitism |
bird on cows back a. commensalism b. mutualism c, parasitism | mutualistic |
tapeworms and humans a. parasitism b. commensalism c. mutualism | parasitism |
what are the 4 of the major 6 biomes | desert, grassland, rain forest, tundra, taiga, deciduous |
how much is lost between trophic levels | 90% |