COMMUNITY ECOLOGY

SPECIES INTERACTIONS Remember populations have interacting

members a specific species. Communities have interacting members

of different species. Think about your neighbor hood. You

people, cats, dogs, birds etc. all living in the same community.

PREDATION An individual of one

species, called the predator. It eats all or part of an individual of another species called prey.

Predation is a very important part of ecology. It tells how big or small a population could be and how each species live.

PREDATOR ADAPTATIONS Natural Selection favors the evolution if

predator adaptations for finding, capturing and consuming prey.

Snakes for example have heat pits that sense prey without having to look at them.

Survival depends on how well an organism captures food however it also depends on how well you can hide or avoid getting captured.

ADAPTATIONS IN ANIMAL PREY

Ways animals avoid being eaten.

Mimicry- where one species closely resembles another species.

Plants use sharp thorns, spines, sticky hairs and tough leaves.

COMPETITION Interspecific competition- a type of interaction

in which 2 or more species use the same limited resource. (lions, hyenas)

SYMBIOSIS Close, long term relationship between 2

organisms. Parasitism, mutualism and

commensalism.

PARASITISM A

relationship in which one individual is harmed while the other benefits.

It does not result in death of the host.

Tapeworms

MUTUALISM This is where

both organisms benefit.

Pollination of plants by animals.

COMMENSALISM One organism

benefits but the other organism is neither hurt nor benefits.

Cattle egrets and Cape buffalo

PATTERNS IN COMMUNITIES Species Richness- the number of species

in the community. Species Evenness- relative abundance

of a species. This takes into account how common each species is in a community.

Simple count of the species of the community.

SUCCESSION Ecological succession- gradual,

sequential re-growth of a community. Primary succession- the development of

a community in an area that has not supported life previously.

Secondary succession- sequential replacement of species that follows disruption of an existing community.