AP Bio - Unit 8: Ecology (overview)

what is ecology

study of organisms ond their environment

types of species distribution

uniform (brids, plants), random (plants), clumped (animals, shows social-ness)

density equation

D = n/a

n = # of species a = area size

abundance

size, ,methods of measuring:

* quadrats
* mark and recapture
* lincoln peterson index estimate populaiton size from M&R data
* N = (M\*S)/R
* M = # marked
* S = size of second sample
* R = # marked in recapture

demography

graphs show percent of population by age

left = increasing pop.

middle = stable pop.

right = decreasing pop.

life history

pattern of survival (when they first reproduce, how many offspring, how many reproductive cycles)

fecundity

the ability to make offspring

suvivorship curve

graph that shows # of births in relation to survival

red = K selection, high infant survival rate, less offspring

blue = constant death rate

green = R selection, high infant death, lots of offspring

formulas for populaiton growth

Birth rate(B) = # births/time

Death rate (D) = # deaths/time

per capita birth (b) = B/n (total population)

per capita death (d) = D/n

exponential growth rate = b-d also written as r (used for population calculations without carrying capacity)

if…

* r>0 = incline
* r

density dependent factors

competition, predation, disease, ect

density independent factors

natural disasters, climate change, ect

community

the study of interspecific interation of populaitn of different species

ecological niche

a particular role that a species has in a community

interspecific interaction relationships (and who benefits)

* competition (neither)
* predation (one)
* herbivory (one)
* parasitism (one)
* commencalism (one benefits, other isnt bothered)
* mutilism (both)

food webs

a way to map energy flow in a community

10% rule

approximently 10% of energy move up a trophic level

keystone species

a species that other species in a community rely on

invasive species

non-indigenous speciese that can cuse harm to the balence of an ecosystem

simpson’s diversity index

measures diverity, more diversity = better health

D = 1-Σ(n/N)^2

n = # of species in community

N = total individual