all organisms of the same kind that are genetically similar enough to breed
all members of species living in a given area at the same time
all of the populations of organisms living in the same area interacting with each other.
-all are interdependent
the biological community, the living community
the physical environment, the non-living components
organisms become adapted in a way that lessens the energy needed to survive and which increases the success of survival
-affected by biotic, abiotic, and habitat.
2 types of niches
Fundamental and realized
potential ecological niche for an organism
-does not have it, just potential.
niche an organism already occupies
Consequences of Limiting resources
-restricts an organisms niche
-may lead to competitive exclusion
-leads to resource partitioning
two or more individuals attmepting to use the same resource
2 types of competition
intraspecific and interspecific
(competition) Intraspecific competition
among individuals within a population
(competition) Interspecific competition
between different species
Competition exclusion principle
-two species cannot occupy the same niche in the same community for an indefinte period.
- -one species is excluded by another as a result of competition
- ex) extinct or resource partitioning
Effects of competition
species evolve more efficient ways to interact
(symbiotic relationships) Mutualism
each individual organism benefits from this relationship
(symbiotic relationships) Comensalism
one organism benefits while the other remains neutral
(symbiotic relationships) Parasitism
One organism benefits while the other one is harmed
Adaptations that allow a species to defend against predation
-poisons or toxins
-mechanical defenses( claws, sharp teeth)
-associating in groups (herding)
present in small numbers but are crucial in determining teh species composition and ecosystem functioning
affect the community because they are so common
occurs in an area not previously inhabited
-starts with rocks present only
-occurs where there is a pre-existing community and well-formed soil
-most common after a forest fire.
Intermediate disturbance hypothesis
-species richness is greatest at moderate levels of disturbance
photosynthesis, because is it the basis for almost all other growth in an ecosystem.
manufactured of biomass by organisms eating plants...
-aquatic chains tend to be longer
-food webs tend to be simpler in more harsh environments
expression of an organisms feeding status in an ecosystem
Facts on energy pyramid
-smaller organisms are eaten by larger ones
- takes many organisms to feed one large organism