first set of slides 3/21 population ecology Flashcards
Scientific goal of ecology
understanding the factors that influence the size of populations
general principles of pop. ecology
dispersion/immigration/emigration/births/deaths
Practical goal of ecology
management of populations
the three tyeps of population management to achieve the practical goal
Increase population size
decrease population size
maintain population size
when do we need to increase population size
endangered species
decrease population size for what type of species
pests
maintain population size for
maintain & maximize sustained yield
ex. fisheries management
Population
group of individuals of same species in same area at same time
what makes a population what characterisitcs
-rely on same resources
-interact with each other
-interbreed together
populations are going to be influenced by
boundaries and size
factors that relate to pop. ecology is AKA dynamic biological process are influenced by (give all factors)
Density
Dispersion
Demographics
Density
number of individuals per unit area or volume
ex. 6 rabbits per acre
dispersion
pattern of spacing among individuals within the boundaries of the pop
demographics
factors that are going to affect birth and death rates in a population
what do Sampling techniques help figure out
density and total pop. size
3 different ways to do the sampling techniques for density
-Extrapolation from small samples
-An index of population size (e.g., number of nests will have a certain number of eggs in it )
-Mark-recapture method
why do ecologist do sampling techniques
because its impossible to count all organisms in a population you need to estimate
tag
marking organism so they are identifiable in sampling
process of Mark-recapture method
-Capture, tag, release a random sample of individuals
-after giving species time to Mix back into the population
- Capture a second sample, note how many of them are marked
Population size is estimated by a formula
formula for MArk recapture method
N=sn/x