Chapter 45: Ecological Communities Flashcards Preview

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Flashcards in Chapter 45: Ecological Communities Deck (30):
1

community

group of species that coexist and interact with one another within a defined geographic area

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species composition

the particular mix of species in a community and the relative abundances of those species

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True or false: species composition varies along environmental gradients

true

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transect

a straight line used for ecological surveying

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habitat structure

characteristics of the surfaces and the horizontal and vertical distribution of objects

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succession

the relatively predictable way species replace one another after a change in environment

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ecological transition

change to a different community after some types of disturbances

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niche

set of environmental tolerances of a species, which define where it can live and the way in which a species obtains energy and materials and its pattern of interaction with other species in the community

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trophic interactions

consumer-resource interactions cause energy and materials to flow through a community

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primary producers

photosynthetic organisms that manufacture the carbs that fuel their metabolism

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autotrophs

create their own food

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heterotrophs

obtain energy by breaking apart compounds made by other organisms

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Primary consumers

hetertophs that eat primary producers

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Secondary consumers

heterotrphs that eat primary consumers
also called primary carnivores

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tertiary consumers

secondary carnivores
eat primary carnivores

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trophic levels

feeding positions (primary producers, consumers)

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Omnivores

feed from multiple trophic levels

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Decomposers

detritivores
feed on waste products or dead bodies
responsible for the recycling of materials
break down organic into inorganic

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food web

Diagrams that show the flow of energy through trophic interactions

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Gross Primary Productivity (GPP)

the total amount og energy that primary producers capture and convert into chemcial energy during some period of time

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Net Primary Productivity

the energy contained in the tissues that primary producers have produced in an interval of time

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ecological efficiency

how much energy gets converted into biomass

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trophic cascade

ripple effects that cross trophic levels caused by consumer-resource interactions
ex. Yellowstone National Park
no wolves----> lots of elk
lots of elk ----> no new aspen trees
Lots of elk----> hurt streamside willows ---> beavers almost go extinct locally
wolves come back, less elk, more aspen, willows regrow, more beavers

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species diversity

made up of two components
species richness and species evenness

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Species richness

the number of species in a community

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Species Evenness

distribution of species abundances

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effect of sampling as effect of diversity on community function

more species, more likely to have some that have a strong influence on output

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Niche complimentarity

Communities that contain more species may be better able to use all available resources because they are more likely to include species that have complimentary niches

29

Theory of island Biogeography

offshore island only gains species if they colonize from elesewhere
the rate at which new species arrive on an island must decline as the island fills-- as island fills up, many new individuals are from species already there
overall rate at which species lost-- extinction rate-- must increase as idland fills with species
number of species on an island (species richness) stops changing when colonization rate = extinction rate

30

ecosystem services

things that ecosystems do