Ecology Chapter 10 Flashcards
game theory
branch of mathematical theory and equations to provide a reason for why people decide the things they do (completx systems)
benefits of group living
defense against predators
increased foraging ability
access to grooming
easy to find a mate
drawbacks of group living
increased susceptibility to diseases (bacteria&viruses)
sharing food (competition)
competition for mates
group living as a way to deal with predator benefits
- encounter dilution or ‘selfish herd’ hypothesis
- many eyes hypothesis
- predator confusion hypothesis (fish example)
per capita
rate of describing per head, per person, per individual
population dynamics: N
number of individuals in the population
population dynamics: N(t)
number of individuals at any given time
population dynamics: N(0)
number of individuals in the population at t=0 or point when observation first starts
population dynamics formula in terms of elephant example
Nt+1=Nt=B-D
N= # of elephants B= births D= deaths t= number of elephants today
B=bNt
B= # of births b= birth rate N= # of species t= time
dN/dt= rN
r= instantaneous per capita rate of increase N= population size
what does n=0 or r=0 mean?
the population is stable
what does r > 0 mean?
the population is growing
what does r
the population is shrinking
assumptions of the population dynamics model
- all individuals contribute equally to population growth or decline
- r is a constant - environment is unlimited
Nt= No^ert
equation essentially the same equation as compound of interest
e is logarithum number on calculator
Discrete model handles what?
geometric population growth
Nt+1=Nt (lambda)
use this equation when solving for one time step
(lambda) is multiplier, population growth rate
what does lambda have to be for a population to be stable? growing? declining?
stable - 1
growth > 1
decline
Nt = (lambda)tNo
use this equation when calculating future time step (50 years)
intraspecific
within a species - bunnies compete with other bunnies
if resources become limiting when a population size increases… what occurs?
limited growth
density dependence
negative density dependence
what is limited growth caused by
limited growth is caused by changes to birth
density dependence
density dependence occurs when per capita population growth rate changes with population density
negative density dependence
negative density dependence increases in death rate and/or decreases in birth rate as population density increases
why does birth/death rate change with population density?
intraspecific competition
