Ch 54 Community Ecology Flashcards
Interspecific interactions
Relationships between species in a community
Interspecific interactions can affect the 1)___ and 2)___ of each species
1) Survival
2) Reproduction
Interspecific competition (-/-)
Two or more species compete for a resource that is in short supply
Predation (+/-)
One species (predator) kills and eats the other (prey)
What does predation lead to?
Diverse adaptations, including mimicry
Herbivory (+/-)
An herbivore eats part of plant or alga
Plants have various 1)___ and 2)___ defenses against 3)___
1) Chemical
2) Mechanical
3) Herbivory
Symbiosis
Individuals of two or more species live in close contact with one another
Three types of symbiosis:
1) Parasitism
2) Mutualism
3) Commensalism
Parasitism (+/-)
The parasite derives its nourishment from a second organism (host), which is harmed
Mutualism (+/+)
Both species benefit from the interaction
Commensalism (0/+)
One species benefits from the interaction, while the other is unaffected by it
Facilitation (+/+ or 0/+)
Species have opposite effects on the survival and reproduction of other species without the intimate contact of a symbiosis
Competitive exclusion principle
States that two species competing for the same limiting resources cannot coexist in the same place
Ecological niche
The total of a species’ resources
Resource partitioning
One or more significant differences between species’ niches
Similar species can coexist if there is ___ ___
Resource partitioning
Competition can results in animal’s 1)___ ___ being smaller than its 2)___ ___
1) Realized niche
2) Fundamental niche
Fundamental niche
The full range of conditions under which an animal can potentially exist
Character displacement
A tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
Cryptic coloration
Camouflage
Makes prey difficult to spot
Aposematic coloration
Bright warning coloration
With what kind of species is aposematic coloration associated with?
Animals with effective chemical defenses
Batesian mimicry
A palatable (harmless) species mimics an unpalatable (harmful) model
Mullerian mimicry
Two or more unpalatable species resemble each other
Species diversity
The variety of organisms that make up the community
Two components of species diversity
1) Species richness
2) Relative abundance
Species richness
The number of different species in the community
Relative abundance
The proportion each species represents of all the individuals in the community
Shannon diversity
H = -( pA ln pA + pB ln pB +…)
Communities with higher diversity can be:
1) More reproductive and more stable in their productivity
2) Better able to withstand and recover from environmental stresses
3) More resistant to invasive species
Invasive species
Organisms that become established outside their native range
Trophic structure
The feeding relationships between organisms in a community
Food chains
Link trophic levels from producers to top carnivores
Food chains can have a key role in ___ ___
Population dynamics
Food web
A branching food chain with complex trophic interactions
In a food web, species may play a role at more than one ___ ___
Trophic level
Two hypotheses as to why even complex food webs posses food chains that are usually only a few links long.
1) Energetic hypothesis
2) Dynamic stability hypothesis
Energetic hypothesis
Suggests hat length is limited by inefficient energy transfer
Dynamic stability hypothesis
Proposes that long food chains are less stable than short ones
Dominant species
Species that are most abundant in a community
Keystone species
Species that exert strong control on a community by their ecological roles (or niches) without necessarily being abundant
Intermediate disturbance hypothesis
Suggests that moderate levels of disturbances can foster greater diversity rather than either high or low levels of disturbance
Species-area curve
Quantifies the idea that, all other factors being equal, a large geographic area has more species
Species richness on islands depends on:
1) Island size
2) Distance from the mainland
3) Immigration
4) Extinction
Equilibrium model of island biogeography
Maintains that species richness on an ecological island levels off at a dynamic equilibrium point
