1. Chapter 15 Populations

2. Section 1
Population- all the individuals of a species that live together in one place at one time

3. Demography- statistical study of populations

4. A) Population Size- The number of individuals in a population.
Key Features
A) Population Size- The number of individuals in a population.
--very small populations are more likely to become extinct and experience inbreeding

6. B) Population density- number of individuals that live in a given area
--affects reproduction

8. C) Dispersion- the way individuals of the population are arranged in a space
3 Types

9. Random

10. Even

11. Clumped

12. Growth rate- difference between the birth rate and death rate

13. Immigration – Organisms moving into a population
Emigration – Organisms moving out of a population

14. Exponential Growth Curve- rate of population growth stays the same, population size increases steadily.
Produces a J-shaped curve.

17. Carrying capacity- population size that an environment can sustain (K)-based on resources

18. Density-Dependent Factors- a variable affected by the number of organisms present in a given area (resources)

20. Logistic Growth Curve- takes into account declining resources.
Produces an S-shaped curve

22. Density-Independent Factors- variables that affects a population regardless of the population density (climate, weather, etc.)

27. r-strategists- species adapted for living in an environment where changes are rapid and unpredictable.

29. Capybara
World’s largest rodent
300 lbs., 2 ft. tall

30. exponential population growth (insects, plants, bacteria)
Characterized by:
rapid growth
high fertility
short life span
small body size
exponential population growth (insects, plants, bacteria)

31. k-strategists- species characterized by slow maturation, few young, slow population growth, reproduction late in life and population density near carrying capacity

33. How Populations Evolve
Section 2
How Populations Evolve

34. Hardy-Weinberg Principle- frequencies of alleles in a population do not change unless evolutionary forces act on the population

35. Evolutionary Forces
1) Mutation- very slow

36. 2) Gene flow- the movement of individuals to or from a population (Migration)

37. 3) Nonrandom mating- inbreeding

38. 4) Genetic drift- The frequency of an allele in a population is greatly changed by a chance event (fire, landslide)

40. 5) Natural Selection – Survival of the fittest (Charles Darwin)