AP Bio - Ch.40-43: Ecology

population

group of individuals of the same species living in the same area

community

a group of populations

ecosystem

community of organisms and the physical factors that they interact with

habitat

the “area” / place. the physical embodiment of an animals ecological niches

dispersion

pattern of spacing among individuals within the boundaries of the population

dispersal

the movement of individuals or gametes away from area of origin

clumped

pattern of dispersion involving aggregation. often associated with mating behaviors

uniform

pattern of dispersion involving spaced separation. often associated with territorial behavior

random

pattern of dispersion lacking a perceivable pattern. associated with neither attractive nor repulsive factors.

density

mass over volume. calculates number of individuals per unit area of volume

logistic

________ function can be used to determine population changes.

r — per Capita change

N — population change

t — time

K

Carrying capacity (the maximum amount).

When N=K, population stops growing.

K-selection

Traits advantageous for high density environments

r-selection

Traits that maximize reproduction in small environments

Density-independent factors

Affect populations, but do not rely on population densities

eg. natural disasters

Density-dependent factors

Affect populations and rely on population densities

eg. scarcity of resources, disease

intraspecific competition

competition that exists within a population (same species)

interspecific competition

Ecological Interaction. (- / - )

Competition that exists within a community (different species)

Ecological Niches

Sum of the species (specific) use of biotic and abiotic resources in an environment

• “preferences” that, if infringed by another competitor, results in intra/interspecific competition

  • depends on the species of the competitors (same species/difference species)

Sympatric populations

Populations that tend to have a greater variance in traits due to geographical overlap (increased competition)

Allopatric populations

Populations that have more consistent traits from being geographically more spread out

Ecological interactions

how organisms interact in an ecosystem

Made up of three main broad categories:

• Competition ( - / - )

• Exploitation ( + / - )

• Positive Interaction ( + / + )

Parasitism

Ecological Interaction ( + / - )

• ectoparasitism — feed off of host surface level

  • endoparasitism — feed off of host from within

Predation

Ecological Interaction ( + / - )

One organism preying upon another organism.

Herbivory

Ecological Interaction ( + / - )

The consumption of plant matierla by animals

Mutualism

Ecological Interaction ( + / + )

Symbiosis that is beneficial to both organisms involved.

Commensalism

Ecological Interaction ( + / 0 )

Association where one organism benefits off of the other, while the other doens’t necessarily get any benefits nor harm

Trophic positions

position an organism occupies within a food chain

Primary Producers

(Trophic position)

Autotrophs — convert their own energy from the sun

Primary Consumers

(Trophic position)

Herbivores (first to consume autotrophs)

Secondary Consumers

(Trophic position)

Carnivores that eat herbivores

Tertiary Consumers

(Trophic position)

Carnivores that consume other carnivores.

Detrivores

(Trophic position)

Decomposers — obtains nutrients from nonliving things