Biology (Unit 1): Species Interactions & Community Structure

What is competition?

when two organisms need the same limited resource

What is the effect of competition on the species involved?

both are harmed, since they must share a limited resource

What is predation?

when one organism hunts and eats another

What is herbivory?

when an animal eats a plant, often without killing it

What is the difference between predation and herbivory?

predation usually kills the prey, while herbivory often just damages the plant

What is symbiosis?

a close, long-term relationship between two different species

What are the three symbiotic relationships?

mutualism, commensalism, and parasitism

What is mutualism?

a relationship where both species benefit

What is commensalism?

a relationship where one species benefits and the other is unaffected

What is parasitism?

a relationship where one species benefits and the other is harmed

Why is competition not counted as symbiosis?

it is not a close long-term partnership between two specific species

What is the difference between intraspecific and interspecific competition?

intraspecific is within one species, while interspecific is between different species

What is a memory hook for intraspecific competition?

intra means within, like within a single species

What happens to intraspecific competition as density rises?

it increases, as more individuals compete for the same resources

What is resource partitioning?

when species divide up a shared resource to avoid direct competition

Give a few ways species can partition a resource?

by using different areas, different times, or different parts of the resource

What is the competitive exclusion principle?

two species cannot coexist if they compete for exactly the same niche, as one will outcompete the other

How does resource partitioning let species coexist?

by using the resource differently, they avoid competing directly

How do species interactions shape a community?

they influence which species survive and how populations are controlled

How can adding or removing one species change a whole community?

its interactions ripple outward, affecting many other species

Give an example of one species reshaping a community?

reintroducing a predator can reduce prey numbers and let plants recover