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<0 = decline
r=0 = no change
logistic growth = r(n)((k-n)/k)
k = carrying capacity
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