Community Ecology Flashcards
what is a community?
interacting populations at a particular location
What is a community characterized by?
- species richness (number of species present)
- Primary productivity (amount of energy produced)
What is a niche?
give examples
the total of all the ways an organism uses the resources of its environment
ie:space utilization, food consumption, temperature range, appropriate conditions for mating, requirements for moisture and more
What is interspecific competition?
occurs when two species attempt to use the same resource and there is not enough resource to satisfy both
*there has to be a limited resource for competition to exist
What is interference competition?
physical interaction over access to resources
What is exploitive competition?
consuming the same resources
What is a fundamental niche?
entire niche that a species is capable of using based on physiological tolerance limits and resource needs
What is a realized niche?
actual set of environmental conditions, presence or abundance of other species, in which the species can establish a stable population
Who was the man who did the classical study of barnacles?
J.H.Connells
Can species with identical resource requirements coexist?
no
sympatric lizards have developed_____________ to avoid direct competition
subdivided niche
_______ is often seen in similar species that occupy the same geographic area. This results from what?
resource partitioning; natural selection
What is character displacement
difference in morphology evident between sympatric species
What is predation?
consuming of one organism by another
True or False:
predation strongly influences prey populations?
true
give an example of an animal that does chemical defense
monarch butterfly caterpillars feed on milkfeed and dogbane families and incorporate cardiac glycosides into their body
Give two things that characterize defense of coloration
- poisonous animals use warning coloration
- organisms that lack chemical defencies are seldom brightly colored (camouflage or cryptic coloration)
What does mimicry allow a species to do?
capitalize on defensive strategies of another
What is Batesian mimicry?
mimics look like distasteful or predatory species
What is Mullerian mimicry?
several unrelated but poisonous species come to resemble one another
What is symbiosis?
2 or more organism interactions in a long-term association
What are the three types of symbiosis?
Commensalism
Mutualism
Parasitism
Describe commensalism
one organism benefits while the other isn’t harmed
Describe Mutualism
both organisms benefit
Describe Parasitism
one organism benefits while the other is harmed
What are the two types of external parasites?
ectoparasites
parasitoids
Describe Ectoparasites
Feed on exterior surface of an organism
Describe parasitoids
insects that lay eggs on living hosts
ie: wasp
The only type of internal parasites are endoparasites. Describe them
- live inside the host
- extreme specialization by the parasite as to which host it invades
- many parasites have complex life cycles involving more than one host
describe taxoplasmosis
Does predation reduce or increase competition
reduces
*look at slide 25
What is an indirect effect of species interactions?
presence of one species may affect a second by way of interactions with a third species
What are Keystone species?
species whose effects on the composition of communities are greater than one might expect based on their abundance
- Keystone species can manipulate the environment in ways that create new habitats for other species
ie: Beavers
Describe succession
communities have a tendency to change from simple to complex
What is the difference between Primary and Secondary Succession?
primary succession occurs on bare, lifeless substrate (open water, rocks) while secondary succession occurs in areas where an existing community has been disturbed but organisms still remain (field-left uncultivated, forest after a fire)
early successional species are characterized by ________
r-selected species
What is facilitation?
early successional species introduce local changes in the habitat
(k-selected species replace r-selected)
Communities are constantly changing due to what?
3 things
- ) climate changes
- ) species invasion
- ) disturbance events
nonequillibrium models that emphasize______ rather than____ are used to study communities and ecosystems
change; stability
What is the intermediate disturbance hypothesis?
communities experiencing moderate amounts of disturbance will have higher levels of species richness than communities experiencing either little or great amounts of disturbance
