1. Ecosystems and Living Organisms
Chapter 4
Ecosystems and Living Organisms

2. Evolution Genetic changes in a population through time.
Occurs through natural selection
Overproduction
Variation
Struggle for existence
Differential reproductive success

3. Evolution
Darwin’s Finches

4. Evolution
Kingdoms of Life

5. Biological Communities
Rotting Log Community

6. Biological Communities
Succession:
How Communities Change over Time
Primary succession –
Rocks
Lichens
Mosses

7. Biological Communities
Succession: How Communities Change over Time
Primary succession –
Rocks
Lichens
Mosses
Grasses
Shrubs

8. Biological Communities
Succession: How Communities Change over Time
Primary succession –
Rocks
Lichens
Mosses
Grasses
Shrubs
Trees

9. Biological Communities
Secondary Succession

10. Interactions Among Organisms
Symbiosis –
one species living in or on another species
results from coevolution

11. Interactions Among Organisms
Symbiosis –
Three types
1) Mutualism
With mycorrhizae
Without mycorrhizae

12. Interactions Among Organisms
Symbiosis –
Three types
2) Commensalism
Epiphytes

13. Interactions Among Organisms
Symbiosis –
Three types
3) Parasitism
Tracheal mites

14. Interactions Among Organisms
Predation – predators consuming prey
Most common method: Pursuit and Ambush

15. Interactions Among Organisms
Animals that consume plants = herbivores
Animals that consume animals = carnivores
(can be further subdivided based on prey type, such as an insectivore)

16. Interactions Among Organisms
Defenses against predators:
Plant defenses –
spines, thorns
leathery leaves
toxic chemicals
thick waxes

17. Interactions Among Organisms
Defenses against predators:
Animal defenses –
armor, spines
toxic chemicals

18. Interactions Among Organisms
Defenses against predators:
Animal defenses –
armor, spines
toxic chemicals
camouflage
running away

19. Interactions Among Organisms
Competition –
individuals attempting to utilize common resources
Intraspecific competition
Interspecific competition

20. The Ecological Niche
An organism’s adaptations, use of resources, lifestyle, and habitat.
Fundamental vs. Realized Niche
Example: Tale of Two Anoles
Green Anole
Brown Anole

21. The Ecological Niche Fundamental vs. Realized Niche
Fundamental Niche of Green Anole
Fundamental Niche of Brown Anole
Overlap
Brown anole out-competes green anole, therefore . . .

22. The Ecological Niche Fundamental vs. Realized Niche
Realized Niche of Green Anole
Realized Niche of Brown Anole
Overlap

23. The Ecological Niche
Limiting Resources

24. The Ecological Niche
Competitive Exclusion

25. The Ecological Niche
Competitive Exclusion

26. The Ecological Niche
Competitive Exclusion

27. The Ecological Niche
Resource partitioning

28. Keystone Species
Single species that strongly influences an entire community.
Example: figs
- frugivores depend upon fruit
- usually avoid figs, but during certain times of the year, figs are only species bearing fruit
- if figs were eliminated, many frugivores would die out

29. Species Richness
Number of different species in a community

30. Species Richness Forest Grassland ECOTONE Where edge effect occurs
Typically greater species richness

31. Species Richness Species Richness and Ecosystem Services Ecosystem
Forests, Grasslands
Purify air / water
Produce / maintain soil
Absorb CO2
Wildlife habitat
Freshwater systems
Moderate water flow
Mitigate flooding
Dilute / remove pollutants
Drinking water
Recreation

32. Species Richness Species Richness and Community Stability
Greater the richness = Greater the stability