Section 1.2 NOTES

Studying Populations

II A. DETERMINING POPULATION SIZE:

How do you determine the population size of a species?1. Direct Observation2. Indirect Observation3. Sampling4. Mark and Recapture

II A. Match The MethodsCounting Individual organisms Indirect Observation

Counting organisms in a small sample then projectting to a larger, similar area Mark and Recapture

Locating nests and estimating organismsper nest Sampling

Capturing, Marking, then recapturingAnd using the frequency of recapturing Direct ObservationTo determine Population Size

II B. Changes in Population Sizes

• When New Members Join or Leave a Population1. Birth and Death Rates 2. The Population Statement3. Immigration and Emigration4. Graphing Changes in Population5. Population Density

1.Births and Deathsa.Births = additions, Deaths = subtractions

2.The Population Statementa.Birth Rate > Death Rate = Population increasesb.Birth Rate < Death Rate = Population decreases

3.Immigration and Emigrationa.Individuals moving INTO a populationb.Individuals moving OUT of a population

4.Graphing Changes in Population5.Population Density

a.Number of individuals / Unit area

4. Graphing Changes in a Population

Thomas Austin of England introduced introduced 24 breeding rabbits in October 1859 as game for shooting parties… BIG

MISTAKE!

Population Density

• The number of individuals in an area of a specific size• Population growth and resulting higher population

density is often argued to lead to increased stress on water and natural resources, decreased food security.

II C. Limiting Factors (abiotic resources)1. Environmental factor that causes a population to

decreasea. Food and Waterb. Space

i. Carrying Capacity1. The largest population that an area can

support.c. Weather

Carrying Capacity is the largest population an area can support.

Section 1.3 NOTES

Interactions Among Living Things