Ecology Flashcards
What is population defined by?
Size, density, and dispersion
Size
Total number of individuals in a population: births, deaths, immigration, emigration
Density
Number of individuals per unit area or volume
Dispersion
Pattern of spacing of individuals: clumped, uniform random spacing
Biotic potential
The maximum rate at which a population could increase under ideal conditions
What factors influence a population’s biotic potential?
- Age at which reproduction begins
- Life span capable of reproducing
- Number of reproductive periods in lifetime
- Number of offspring capable at 1 time
Carrying capacity(K)
The maximum that the environment can support
r-strategists
- Reproduce rapidly when uncrowded and resources are vast
- Many, small young
- Little parenting
- Rapid maturation
- reproduce once
- Insects
K-strategists
- Maximize population size near the carrying capcity
- Few, large young
- Intensive parenting
- slow maturation
- Reproduce many times
- Mammals
Limiting factors
- Limit population growth
- Density-dependent factors and Density-independent factors
Density-dependent factors
- Increase directly as the population density increases
- Competition for food, buildup of wastes, predation, disease
Density-independent factors
- Occurence is unrelated to the population density
- Natural disasters
Population interactions
Competition, predation, parasitism, mutualism, commensalism
G. F. Gause
Competitive exclusion principle
Competitive exclusion principle
-2 species can’t coexist in a community if they share a niche, if they compete for the same resources
What happens if 2 species share the same niche in a community?
- extinction
- Evolve through natural selection to exploit different resources - resource partitioning
- character displacement(divergence in adaption)
Character displacement
adaptive radiation
Resource partitioning
Evolve through natural selection to exploit different resources
Passive defenses against predators
- Aposematic coloration
- Batesian mimicry
- Mullerian mimicry
Aposematic coloration
Bright coloration of poisonous animals is a warning that predators should avoid them