1. Climate and Biomes
Evolution and Adaptation
Population Ecology

2. Attributes of Populations
Population Ecology
Attributes of Populations
- Population: A group of potentially interbreeding organisms at the same time and place, that share a common gene pool.
- Population size : number of individuals
- Population Growth Rate: change in number over time, as a function of
(birth +immigration)- (death + emigration)
- Population density : number per unit area
- Range/distribution: geographic area over which the individuals are dispersed.
- Population Structure:
- age class structure
- sex ratio
- genetic structure
- spatial structure (pattern of how individuals are distributed through the range)

3. Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance – the Niche Concept
Fremont’s Leather flower

4. Attributes of Populations Distributions A. Determining Factors
Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance
Realized and fundamental niches
Zones of optima, tolerance, intolerance
soil moisture
temperature
performance

5. Attributes of Populations Distributions A. Determining Factors
Population Ecology
Attributes of Populations
Distributions
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal

6. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration

7. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change

8. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change
Changes in elevational range
cooler
warmer

9. Craig Moritz,1,2. James L. Patton,1,2 Chris J. Conroy,1 Juan L
Craig Moritz,1,2* James L. Patton,1,2 Chris J. Conroy,1 Juan L. Parra,1,2 Gary C. White,3 Steven R. Beissinger1, Impact of a Century of Climate Change on Small-Mammal Communities in Yosemite National Park, USA. Science 322:

10. Craig Moritz,1,2. James L. Patton,1,2 Chris J. Conroy,1 Juan L
Craig Moritz,1,2* James L. Patton,1,2 Chris J. Conroy,1 Juan L. Parra,1,2 Gary C. White,3 Steven R. Beissinger1, Impact of a Century of Climate Change on Small-Mammal Communities in Yosemite National Park, USA. Science 322:

11. 1. Environmental Tolerance
A. Determining Factors
1. Environmental Tolerance
2. Barriers to Dispersal
3. Changes thru Time: Seasonal Migration
4. Changes thru Time: Climate Change
5. Niche Modeling and Invasive Species

12. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.

13. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.

14. Probabilities of three Eucalyptus species being found in an area, mapped by climate and soil type.

15. Problems:
Doesn’t account for biological aspects of the environment
- maybe the native range is limited by competition/predation
- separated from that competitor/predator, the range may increase
Water Hyacinth
“Biological Control Agent”
Neochetina eichhorniae

16. Problems:
Doesn’t account for biological aspects of the environment
- maybe the native range is limited by competition/predation
- separated from that competitor/predator, the range may increase
Doesn’t account for the possibility of adaptation

17. A. Determining Factors
B. Dispersion – how organisms in a population are spaced

18. B. Dispersion
- Regular
Low variance

19. B. Dispersion - Regular - intraspecific competition - allelopathy
- territoriality

20. B. Dispersion - Clumped - patchy resource - social effects
- limited dispersal
High variance

21. B. Dispersion - Random - canopy trees, later in succession
Normal distribution

22. B. Dispersion
- Complexities
Varies with type of dispersal

23. B. Dispersion
- Complexities
Varies with life-history stage

24. B. Dispersion - Complexities
Varies with spatial scale and resource distribution

25. 1. Correlates with Niche Parameters – greatest at center of range
C. Population Density
1. Correlates with Niche Parameters – greatest at center of range
Density of Dickcissel, a prairie songbird

26. C. Population Density 2. Habitat Selection
Fretwell – Lucas model of habitat selection (1972)

27. 3. Maintenance of Marginal Populations
C. Population Density
3. Maintenance of Marginal Populations
Why don’t these adapt to local conditions?