Unit 1

What is an ecosystem?

combo of abiotic + biotic factors

What is symbiosis + 3 types?

symbiosis: ecological relationship between organisms of different species

mutualism - both species benefit (bees, flowers)

commensalism - one benefits, other is unaffected (birds nesting in trees)

parasitism - one benefits, other is harmed (ticks, dogs)

What are the 2 types of competition?

intraspecific - same species

interspecies - different species

What is resource partitioning?

organisms “partitioning” the resources in an environment - organisms adapt accordingly

What are keystone species?

species with a dramatically large effect on an ecosystem relative to its abundance - think key that keeps all things from tumbling

• if it were removed, it would have drastic effect on ecosystem

What is niche differentiation/partitioning?

• The idea that species reduce competition by using different resources or using the same resources in different ways.

• This happens when there are multiple types of resources or niches, so organisms specialize (for example: different food types, times of activity, or habitats).

• Result: species can coexist.

What is the competitive exclusion principle?

• States that two species cannot occupy the exact same niche in the same environment indefinitely.

• If they compete for the same limiting resource, one will eventually outcompete the other.

• Result: one species is excluded unless niche differentiation occurs.

What is a niche?

A niche is the set of environmental conditions and resources a species uses and its role in the ecosystem.

Flora vs fauna communities?

flora - plant community

fauna - animal community

Biome example: