Ch 54 A Flashcards
A biological _______ is an assemblage of populations of various species living close enough for potential interaction
Community
Ecologists call relationships between species in a community _______
interspecific interactions
_______ (–/– interaction) occurs when species compete for a resource that limits survival and reproduction
Competition
Resources must be in _______ supply for competition to occur
short
Strong competition can lead to _______
competitive exclusion
What is competitive exclusion?
local elimination of a competing species
Russian ecologist _______ concluded that two species competing for the same limiting resources cannot coexist permanently in the same place
G.F. Gause
An _______ is the sum of an organism’s use of biotic and abiotic resources; it can be thought of as an organism’s ecological role
ecological niche
Birds feeding at different levels of water and shore is an example of?
spatial partitioning
_________ is differentiation of ecological niches, enabling similar species to coexist in a community
Resource partitioning
In ________:
- Both species are normally nocturnal (active during the night)
- Where they coexist, the golden spiny mouse becomes diurnal (active during the day)
Temporal partitioning
A species’ _______ is the niche potentially occupied by that species
fundamental niche
A species’ ________ is the niche actually occupied by that species
realized niche
_______ is a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
Character displacement
Character displacement is a tendency for characteristics to be more divergent in _______ populations of two species than in _______ populations of the same two species
sympatric; allopatric
occurring within the same geographical area; overlapping in distribution.
Sympatric
occurring in separate non-overlapping geographical areas
Allopatric
_______ refers to any +/– interaction in which one species benefits by feeding on the other species
Exploitation
What are the 3 exploitative interactions?
1) predation
2) herbivory
3) parasitism
_______ (+/– interaction) refers to an interaction in which one species, the predator, kills and eats the other, the prey
Predation
Predators have _______ that enable them to find, identify, catch, and subdue their prey
adaptations
Prey display various _______ to avoid being eaten
adaptations
Animals with effective chemical defenses often exhibit bright warning coloration, called _______
aposematic coloration
_______, or camouflage, makes prey difficult to spot
Cryptic coloration
In _______, a palatable or harmless species mimics an unpalatable or harmful model
Batesian mimicry
In _______, two or more unpalatable species resemble each other
Müllerian mimicry
______ has enabled many predators approach prey
Mimicry (ex octopus)
_______ (+/– interaction) refers to an interaction in which an herbivore eats parts of a plant or alga
Herbivory
In _______ (+/– interaction), one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process
parasitism
Parasites that live within the body of their host are called _______
endoparasites (ex tapeworms, Ascaris, flukes)
Parasites that live on the external surface of a host are _______
ectoparasites (ex. leeches, ticks, lice)
Some parasites change the _______ of the host in a way that increases the likelihood that the parasite will be transmitted to the next host
behavior
Ecological communities are heavily influenced by _______ interactions, where at least one species benefits and neither is harmed
positive
What are the 2 types of positive interactions?
1) mutualism
2) commensalism
_______ (+/+ interaction) is a common interspecific interaction that benefits both species
Mutualism (ex. lichen, clam/algae)
_______ (+/0 interaction) is another common interaction in which one species benefits and the other is neither harmed nor helped
Commensalism
Two fundamental features of community structure are _______ and _______
1) species diversity
2) feeding relationships
The _______ of a community is the variety of organisms that make up the community
species diversity
What are the 2 components of species diversity?
1) species richness
2) relative abundance
Two communities can have the _______ species richness but a _______ relative abundance
same; different
Communities with higher diversity are:
- more _______; they produce more biomass (the total mass of all organisms)
- more _______ in their productivity
- better able to _______ and _______ from environmental stresses
- more _______ to invasive species, organisms that become established outside their native range
1) productive
2) stable
3) withstand and recover
4) resistant
_______ is the feeding relationships between organisms in a community
Trophic structure
_______ link trophic levels from producers to top carnivores
Food chains
The position an organism occupies in a food chain is called its _______
trophic level
primary producers are _______
autotrophs
primary consumers are _______
herbivores
secondary consumers are _______
carnivores
A _______ is a group of food chains linked together forming complex trophic interactions
food web
Food webs can be simplified by (2)
1) grouping species
2) isolating a portion of the community
Each food chain in a food web is usually a _______ links long
few
The _______ suggests that length is limited by inefficient energy transfer
energetic hypothesis
explain %energy transfer from sun to tertiary consumers
1% from the sun
10% everywhere else
Food chain length may also be limited by the fact that carnivores tend to be _______ at higher trophic levels
larger
Large carnivores cannot obtain enough food from small prey _______ enough to meet their metabolic needs
efficiently enough (this places a limit on carnivore size)
