Chapter 4: Evolution, Biological Communities, and Species Interactions

1. Chapter 4: Evolution, Biological Communities, and Species Interactions Advanced Environmental Science

2. Section 4.1 Evolution produces species diversity

3. Summary: • artificial selection • natural selection • adaptation in ecosystems • speciation • evolution still at work

4. Artificial Selection

5. Artificial Selection

6. Natural Selection adaptation: the acquisition of traits that allow a species to survive in its environment natural selection: the process of better-selected individuals passing their traits on to the next generations

7. selection pressures: factors in the environment that favor successful reproduction of individuals possessing heritable traits and that reduce viability/fertility of individuals not possessing those traits (examples…)

8. critical factor: the single factor in shortest supply relative to demand tolerance limits: minimum and maximum levels for each environmental factor

9. Adaptation in Ecosystems habitat vs. niche

10. competitive exclusion principle: no two species can occupy the same niche for long (the more successful will exclude the other) resource partitioning: allows several species to utilize the same resource and coexist (examples…)

12. Speciation speciation: development of new species

13. allopatric speciation: geographic barriers cause reproductive isolation sympatric speciation: biological or behavioral barriers cause reproductive isolation (once isolation occurs species diverge genetically)

14. Evolution is still at work… • Galapagos island finches • pesticide resistant insects • drug-resistant pathogens

15. Section 4.2 Species Interactions shape biological communities

16. Competition intraspecific interspecific

17. Predation • Predator-prey relationships exert selection pressures that favor evolutionary adaptation. • Predators become more efficient at searching and feeding, and prey become more effective at escape and avoidance.

18. coevolution: species exert selective pressures on each other and gradually change as a result

21. Predator Avoidance Batesian mimicry: species that are harmless resemble poisonous or distasteful ones Müllerian mimicry: two unpalatable or dangerous species look alike

22. Batesian mimicry

23. Symbiosis mutualism

24. Symbiosis commensalism

25. Symbiosis parasitism

26. keystone species: a species that plays a critical role in a biological community that is out of proportion to its abundance

27. Section 4.3 Community Properties affect species populations

28. primary productivity: rate of biomass production abundance: total number of organisms in a community diversity: number of different species, niches, or genetic variation present in a community

29. complexity: the number of species at each trophic level and the number of trophic levels in a community

30. Stability and Resiliency in Ecosystems constancy: lack of fluctuations in composition or functions inertia: resistance to perturbations renewal: ability to repair damage after disturbance

31. edge effects: changes encountered at the boundary between two ecosystems ecotone: a boundary between two types of biological community *interior area is significant*

32. Section 4.4 Communities are dynamic and change over time

33. Ecological Succession primary succession: succession that occurs in an area where no community existed before secondary succession: succession that occurs in an area where the existing community is disturbed

35. pioneer species: the first species to colonize a new area

36. climax community: the community that develops last and stays the longest • represents the maximum complexity and stability possible • depends on climate and soil

37. disturbance: any force that disrupts the established patterns of species diversity and abundance, community structure or community properties disturbance-adapted species: species that depend on disturbances to succeed