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Wildlife Study Sheet Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Population Ecology

An unders­tanding of how popula­tions of wildli­fe/­species are affected by features of the physical enviro­nment and other organisms

Population Size

*The number of indivi­duals in a population at a given time
*Sudden and dramatic decreases in population size can indicate an unhealthy population headed toward extinc­tion.
*Ecolo­gists often use sampling techniques to estimate population size.

Population Density- how crowded a population is

High population density:
Low population density:
-Larger organisms generally have lower population densities.
More space, resources;
-Finding mates is easier; tends to be more compet­ition; more infectious disease; more vulner­ability to predators
finding mates can be difficult

Limiting Facotors

Enviro­nmental charac­ter­istics slow population growth and determine carrying capacity.
Densit­y-d­epe­ndent:
Influence changes with population density.
ex. parasitism and diseases.

Densit­y-i­nde­pen­dent:
Influence does not change with population density
ex: unusual weather, natural disasters, certain human factors (clear cutting, damming up a river)

Population Distri­bution:

Random
Clumped
Uniform
Organisms arranged in no particular pattern
Organisms evenly spaced
Organisms evenly spaced
How organisms are arranged within an area

Age Structure Diagram

-Relative number of organisms of each age group within population
-Can be used to predict future population growth of a population

Tracking Popula­tions

Biotic Potential

 
An organism’s maximum ability
to produce offspring in ideal conditions

Factors influence biotic potential:
Gestation time
Generation time

Sex Ratio

-Propo­rtion of males to females
-Age structure diagrams give inform­ation about sex ratios.

Methods to Tracking Popula­tions

Complete Counts
Sample Counts
Indirect Methods
Mark and Recapture
Good: -counts EVERY single species in the area -ideal for larger animals -small spaces -ex. Deer drives
Estimate the numbers of animals in the total area by sampling a smaller unit of the total area: Ex. Nets, Quadrats, strip census
Counting organism indirectly (Not actually, physically seeing the organism) Look for SIGNS….
catch a live indivi­dual, tag it, release it, then count the number of indivi­duals marked during new captures.
Bad: Not widely used Expensive Tedious (all animals must be accounted for)
Cons: visibility of animals can be hard, habitat could be difficult, animal behavior
ex.scat, trail cams, tracks
animals can learn to avoid traps animals can become trap happy Marks may injure animals Marking assumes no immigr­ation or emigration (which we know happens) Make them unattr­active to mates
 

Surviv­orship Curve

HIPPO

1. Habitat Destru­ction
2. Introduced Species
3. Pollution
4. Population
5. Overfi­shing