Community Ecology Flashcards
What is a biological community?
Assemblage of populations of various species living close enough for potential interactions
What is the species richness of a community?
The number of species present
What is the primary productivity of a community?
The amount of energy produced by it
What are the two views of structure and functioning of communities (and who is responsible for each of them)?
The individualistic concept; H.A. Gleason
The holistic concept; F.E. Clements
What is the individualistic concept?
A community is nothing more than an aggregation of species that happen to occur together at one place. Favored by most ecologists today.
What is the holistic concept?
A community is an integrated unit; more like a superorganism than the sum of its parts.
How do the species from a community respond to changing environmental conditions?
They respond independently from one another.
What are the two types of interactions that can occur within a community?
Interspecific interactions and intraspecific interactions
What are the symbols used for the effects of interspecific interactions?
+ or - or 0 (no effect in any known way)
What is an ecological niche?
The total of an organism’s use of biotic and abiotic resources in its environment. Combination of habitat, how the organism makes a living and the role performed in the community.
What is interspecific competition?
A +/- interaction that arises from competition for a resource that is in short supply.
What are the two types of interspecific competition (with short description)?
Interference competition (from physical interactions) ` Exploitative competition (from consommation of the same resources)
What is the difference between the fundamental and realized niche?
The realized niche is the actual niche, which may be smaller than the fundamental niche due to competition.
Give an example of competition for niche occupancy (and who is responsible for the study)?I
Competition of Chthamalus stellatus and Semibalanus balanoides for rocky shores. Jo Connell found that for the second, fundamental and realized niches are the same but not for the first.
What is the competitive exclusion principle?
Principle that states that two species competing for limiting resources cannot coexist indefinitely in the same place. One will eliminate the other locally.
Who is responsible for the experiments on competitive exclusion and what were they on?
Experiments by Gause (walmart version of Gauss) and experiments on three species of Paramecium
What is a niche overlap?
The fact that species can coexist if their realized niches do not overlap.
What is resource partitioning and what does it result from?
The fact that species can avoid competition by living in different portions of the habitat or by using different resources. It results from natural selection.
Who studied resource partioning, on what, and what did he observe?
MacArthur studied it on five species of warblers (birds). They all evolved to utilize a different portion of the tree.
3 possible outcomes from predation for Didnium vs Paramecium
1: Predator eliminates prey and then dies due to lack of food.
2: Prey hides in sediment but predator eats those in clear fluid and then dies because no more food.
3: Prey introduced in successive intervals and there is a cyclical pattern.
Give 4 examples of adaption by the prey to diminish the probability of capture
Cryptic coloration (or camouflage), chemical defenses, warning coloration, and mimicry.
What are the two types of mimicry and what is the difference between the two?
Batesian mimicry and mullerian mimicry. In batesian, a harmless specie mimics a dangerous one but in mullerian, several species resemble one another and the predators learn to avoid them.
What is herbivory?
Type of predation (+/-) where herbivore eats plants.
2 plant adaptations against herbivores
Morphological defenses (like spines and thorns) and chemical defenses.
