Chapter 45: Ecological Communities

Question 1

community

Answer 1

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

Question 2

species composition

Answer 2

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

Question 3

True or false: species composition varies along environmental gradients

Answer 3

true

Question 4

transect

Answer 4

a straight line used for ecological surveying

Question 5

habitat structure

Answer 5

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

Question 6

succession

Answer 6

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

Question 7

ecological transition

Answer 7

change to a different community after some types of disturbances

Question 8

niche

Answer 8

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

Question 9

trophic interactions

Answer 9

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

Question 10

primary producers

Answer 10

photosynthetic organisms that manufacture the carbs that fuel their metabolism

Question 11

autotrophs

Answer 11

create their own food

Question 12

heterotrophs

Answer 12

obtain energy by breaking apart compounds made by other organisms

Question 13

Primary consumers

Answer 13

hetertophs that eat primary producers

Question 14

Secondary consumers

Answer 14

heterotrphs that eat primary consumers

also called primary carnivores

Question 15

tertiary consumers

Answer 15

secondary carnivores

eat primary carnivores

Question 16

trophic levels

Answer 16

feeding positions (primary producers, consumers)

Question 17

Omnivores

Answer 17

feed from multiple trophic levels

Question 18

Decomposers

Answer 18

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

Question 19

food web

Answer 19

Diagrams that show the flow of energy through trophic interactions

Question 20

Gross Primary Productivity (GPP)

Answer 20

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

Question 21

Net Primary Productivity

Answer 21

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

Question 22

ecological efficiency

Answer 22

how much energy gets converted into biomass

Question 23

trophic cascade

Answer 23

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

Question 24

species diversity

Answer 24

made up of two components

species richness and species evenness

Question 25

Species richness

Answer 25

the number of species in a community

Question 26

Species Evenness

Answer 26

distribution of species abundances

Question 27

effect of sampling as effect of diversity on community function

Answer 27

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

Question 28

Niche complimentarity

Answer 28

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

Question 29

Theory of island Biogeography

Answer 29

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

Question 30

ecosystem services

Answer 30

things that ecosystems do