1. Population Ecology

2. Biodiversity Biodiversity: variety of organisms in a given area
Review food web
All ecology “linked”

3. Population Growth
Population- all the individuals of a species living together in one place at one time.
Demographics- the statistical study of populations.
Populations size- the number of individuals in the population.
Population density- the number of individuals that live in a given area.

4. Population Dispersion
Uniform-Territoriality and competition for resources lead to individuals living a specific distance apart. Random- Individuals spread randomly in an area. Clumped- Individual live close together in group to help with mating, gain protection, or access resources.

5. Population growth Currently 6 billion people
Growth rate: 90 million per year
Not enough resources
Water, gas, electricity
space

7. Limiting factors-predators, disease, resources
Growth Rates
Exponential growth curve- growth is constant and increasing steadily resulting in a J-shape curve.
Limiting factors-predators, disease, resources

8. Growth Rates r-Strategists- populations that… grow very fast
have short life spans
reproduce quickly
no parental care
live in an unstable environment
ex. Insects

9. Growth Rates k-Strategist- populations that . . . grow slowly
live a longer life
reproduce later in life and fewer times
lots of parental care
live in stable environments
ex: Large mammals

10. Growth Rates Carrying capacity (K)- “maximum occupancy”
the maximum number of individuals of a particular species that the environment can normally and consistently support.

11. Survivorship curves Type I Type II Type III Birth rate High Medium
Mortality rate (infant)
Low
Parental care
none
examples
Large mammals
(humans)
Small mammals, rodents
Invertebrates, fish, amphibians, plants

12. Influences on Growth Rates Limiting Factors
Density dependent factors- water, food,, shelter, competition, predation, parasitism and disease
Density independent factors- weather and climate

13. Population Evolution How does a population change?
Mutations- it happens at a very slow rate and is the source of all variation. Mutations occur in the DNA.
Gene Flow- movement of individuals into a new population (immigration) or out of a population (emigration).
Genetic Drift- a reduction in a particular trait due to a random chance event like a fire. The allele frequency for a trait may be severely affected.

14. Nonrandom mating- also known as artificial selection includes, inbreeding, self pollination, or mates being selected for a particular trait. Farmers will mate only the best producing milk cows. All of the above lead to a population with less variation and an emphasis on a particular trait.

15. Population problem Impound already existing problems
Habitat fragmentation

16. Population problem Impound already existing problems
Pollution (Possible cause of deformations)

17. Population problem Impound already existing problems
Pollution (Increase health risks)
Los Angeles and Mexico City

18. Population problem Impound already existing problems
Pollution (Harming other species)
Sea Lion caught in fishing net

19. Population problem Impound already existing problems
Decrease in biodiversity
extinction: 1987 dusky seaside sparrow
Endangered species: Bengal Tiger

20. Population problem Impound already Decrease in biodiversity
extinction: hunting and illegal commercial harvesting

22. Population problem Impound already existing problems Deforestation
possible medicines
Affects carbon cycle