Ch. 54: Community Ecology

Front 1

community

Back 1

an assemblage of species living close enough together for potential interaction

Front 2

competition

Back 2

interaction is detrimental to both species

Front 3

predation, herbivory, parasitism, disease

Back 3

interaction is beneficial to one species and detrimental to the other

( + / - )

Front 4

mutualism

Back 4

interaction is beneficial to both species

( + / + )

Front 5

commensalism

Back 5

one species benefits, the other is unaffected

( + / 0 )

Front 6

amensalism

Back 6

one species is hurt and the other is neither harmed nor helped

( - / 0 )

Front 7

interspecific competition

Back 7

occurs when resources are in short supply

Front 8

species diversity

Back 8

community is the variety of organisms that make up the community

Front 9

ecological niche

Back 9

sum total of an organisms use of abiotic and biotic resources in the environment

Front 10

invasive species

Back 10

organisms that become established outside their native range

Front 11

resource partitioning

Back 11

differentiation of niches that enable 2 similar species to coexist in a community
(Ex: similar lizzards occupying different levels of forest)

Front 12

character displacement

Back 12

tendency for characteristics to be more divergent in sympatric population of two species than in allopatric populations of the same two species
(Ex: birds change beak depth so they are no longer in sae niche)

Front 13

herbivory

Back 13

animal eats plant

Front 14

parasitism

Back 14

predators live on/in a host and depend on the host for nutrition

Front 15

predator adaptations

Back 15

claws, teeth, fangs, poison, speed, agility
a change in the function of some character leads to its modification

Front 16

cryptic coloration

Back 16

deceptive markings
camouflage

Front 17

mechanical defenses

Back 17

spines

Front 18

chemical defenses

Back 18

odors and toxins

Front 19

aposematic coloration

Back 19

indicated by warning colors and is sometimes associated with other defenses

Front 20

mimicry

Back 20

when organisms resemble other species

Front 21

Batesian mimicry

Back 21

harmless species mimics a harmful one

Front 22

Mullerian mimicry

Back 22

two or more unpalatable species resemble each other

Front 23

endoparasite
ectoparasite

Back 23

lives inside host
lives on surface of host

Front 24

parasitoidism

Back 24

special type of parasitism where the parasite eventually kills the host

Front 25

coevolution

Back 25

when one species evolves, it exerts selective pressure on the other to evolve to continue the interaction

Front 26

trophic structure

Back 26

feeding relationships between organisms in a community

Front 27

food chain

Back 27

link trophic levels from producers to top varnivors
usually 4 or 5 trophic levels

Front 28

energetic hypothesis

Back 28

suggests that the length of the food chain is limited by the inefficiency of energy transfer along the chain

Front 29

food web

Back 29

a branching food chain with complex trophic interctions

Front 30

dominant species

Back 30

have the highest abundance or highest biomass

Front 31

keystone species

Back 31

original species; strong control on a community by their ecological roles

Front 32

bottom-up model

Back 32

community organization proposes an unidirectional influence from lower to higher trophic level

nutrients and vegetation control community organization

Front 33

top-down model

Back 33

proposes that control comes from the trophic levels above

predation controls community organization

Front 34

ecosystem engineers

Back 34

cause physical changes in the environment that affect community structure

Front 35

ecological succession

Back 35

sequence of community changes after a disturbance

Front 36

primary succession

Back 36

begins in a lifeless area where soil has not yet formed

Front 37

disturbance

Back 37

an event that changes a community, removes organisms from it, and alters resource availability

Front 38

species richness

Back 38

total number of species in the comunity

Front 39

relative abundance

Back 39

distribution of the different species

Front 40

species-area curve

Back 40

the larger the geographic region the greater number of species

Front 41

2 factors affecting # of species on island

Back 41

1. rate at which new species immigrate to the island
2. the rate at which species become extinct

Front 42

nonequilibrium model

Back 42

which describes communities as constantly changing after being affected by disturbances

Front 43

intermediate disturbance hypothesis

Back 43

moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance

Front 44

pathogens

Back 44

include disease-causing microorganisms, viruses, viroid's, and prions

Front 45

zoonotic pathogens

Back 45

transferred from other animals to humans

Front 46

vector examples

Back 46

mosquitoes, bugs