Final Exam- Ecology Flashcards
What is Ecology?
The scientific study of how organisms interact with eachother and their environment
Distribution, abundance and the factors that affect these patterns
What are some barriers to dispersal?
Physical and climactic
Ex. Oceans and temperatures
Define Abundance
Measure of the number of individuals of each species in a defined area
Varies with time and location
Define range of tolerance
Range of abiotic conditions in which an organism can survive and reproduce
What determines a species distibution and abundance?
- Dispersal ability: physical structures and climate can act as barriers
- Abiotic factors: Range of tolerance for conditions
List some Abiotic factors
Temperature, light intensity and water availbility
List some biotic factors
Predation, competition, mutualism
Define the intertidal zone
Marine environment that is uncovered and covered each day as the tide rises and falls
What determines the upper limit of distibution for intertidal organisms?
Abiotic stressfull conditions: temperature, salinity, oxygen availbility
Rely upon water trapped in exoskelaton when low tide
What determines the lower limit of distibution in the intertidal zone?
Biotic factors: predation intensity from marine predators, competition for limited resources/space when conditions are optimal
What is the definition of a population?
A group of individuals of the same species that live in the same area at the same time
Lincoln-Pederson method of mark-recapture estimation
N = M x n
m
N = ESTIMATED POP, M = MARKED VISIT 1
n = caught visit 2, m = marked visit 2
What are the assumptions of the Lincoln-Pederson capture/recapture method?
- Population is closed, N doesnt change between sampling periods ex. no birth/deaths
- Individuals do not differ in their probability of being caught ex. marking doesnt affect
- Marks do not come off b/w sampling
Formula for estimating population size at a future time point
Nt+1 = Nt(1 + r)
Per capita birth and death rates
b = B/N
d = D/N
Calculation for growth rate
r = b - d
Per capita growth rate
Expontential population growth
J shape: population in an unlimited environment, r doesnt change no matter how big the pop gets
r is density- independant
Usually short lived, occurs when pop sizes r small
Logistic population growth
S shape: limiting environmental factors restrict pop growth once it reaches carrying capacity (K)
r is density dependant and gets smaller with less resources
Limiting factors
Density-dependant factors
Biotic Factors whos influence on population size or population growth depends upon the number of individuals in a population/density
ex. predation/disease
Limiting factors
Density-independant factors
Abiotic Factors that influence population size and growth regardless of population size/density
ex. volcano eruptions/hurricanes/cold snaps
Define life history traits
Quantification of life history (stages an organism goes through in its lifetime) ex. Age-specific survivorship, age at first reproduction, number of offspring, parental care, reproductive lifespan, growth rate ect.
birth –> growth –> reproduction –> death
Type I surviorship curve
Most of the individuals in a cohort survive until old age
ex. humans and elephants