Unit 8: Ecology (Biology)

ecology

the study of interactions between organisms and the living and nonliving components of their environment.

ecosystem

all of the biotic and abiotic factors of a relatively defined geographic area.

density

populations are described by their location, species, size, ________, dispersion, and dynamics (how they change)

biosphere

the entire spherical location where life is located

population Ecology

focuses on how populations change

growth rate

b-d

ecology

the study of interactions between organisms and the living and nonliving components of their environment

community

All living organisms that live in a relatively defined geographic area

population

a group of organisms, all of the same species, located in a relatively defined geographic area

exponential growth

a populations growth rate remains constant

biodiversity

relates the number of species in a community to the relative abundance of each species

symbioses

species interactions

predation

Predation is when one individual (predator) captures, kills and consumes another individual (prey)

predator-prey cycles

Predator and prey populations change based on the abundance of each other

ecological niche

A unique set of ecological requirements and roles for a given species

niche overlap

the use of a limiting resource by two or more species

competitive exclusion

when one species is driven to extinction (or near extinction) due to competition over a limited resource.

resource partitioning

where species can minimize competition

parasitism

is when one individual (parasite) harms another (host) but the organism is not immediately killed

mutualism

is a cooperative relationship in which both species derive some benefit

commensalism

is when one species benefits from interactions while the other is “unaffected”

succession

the sequential, gradual growth or regrowth of species (usually plants) in an area

climax community

the end of the succession; a “stable” endpoint... Until disturbance “resets” the process

bioindicator

a species (or group of species) whose status gives humans insight into the health of the community

keystone species

a species that has a **very** large effect on the community. The removal of a keystone species may lead to community collapse

endemic species

species that are native to a specific location, and only that location

exotic species

species that are NOT native to a specific location

invasive species

harm members of the community they came to

distance effect

closer to mainland = more diversity

area effect

more space = more diversity

pioneer species

first organisms in primary succession, are quick growing, small, and are quick at reproducing

intermediate disturbance hypothesis

states that diversity is highest with a moderate level of disturbance

primary succession

new species (growth)

secondary succession

regrowth after an event like a wildfire, etc

type 1 survivorship

mortality rates get higher at old age, i.e. humans

type 2 survivorship

mortality rates remain constant throughout a lifetime, i.e. birds

type 3 survivorship

mortality rates are higher at birth/childhood, i.e. trees

logistic growth

exponential growth with a carrying capacity

populations are described by…

location, species, size, density, dispersion, dynamics

trophic levels

1. producers
2. primary consumers
3. secondary consumers
4. tertiary consumers
5. etc

categories that the organisms on a food web/chain are organized into

energy levels

each trophic level leads to a decrease of energy by 90%


1. producers - 100%
2. primary consumers - 10%
3. secondary consumers - 1%
4. tertiary consumers - 0.1%