Population Ecology Flashcards
What is a population?
- Individuals living in an area
- likely they can inbreed
What characteristics do populations have?
- Density
- Sex Ratio
- Gene frequency
- Distrrubution
How do you determine density?
- Indirect methods
- Comparisons
What are some indirect ways to determine density?
- Sweep nets
- Beat samples
- Pitfall trap
- Pheromone trap
What are some direct estimates of density?
- Count per area
- Berlese funnel
- Insects on alfalfa
- Mark + Recapture
What does the total population =? From mark recapture estimates
Total marked/ Proportion marked in the second sample
What are the assumptions of the mark + recapture methods?
- Marks stay on
- Marks dont kill the insects
- Insects dont leave or come into the area
- Mortality of marked and unmarked is the same
What do gene frequencies determine?
Ability to adapt or become resistant
Where are insects often found/distributed?
Often clumped:
- Edges
- Good plants
- Family Groups
What is an indicator of a good plant?
- Nitrogen levels indicated by color of plant
- Plant size
What increases of a population?
Births an immigration
What decreases a population?
Deaths and emigration
What are some intrinsic factors of density?
- fecundity (number of eggs)
- Physiology
- Behavior
- Genetic variability
What are some extrinsic factors of density?
- Weather
- habitat quality
- competitors
- predators
- disease
What is population ecology?
patterns of population change
