1. Environmental Science © 2012 W. H. Freeman and Company
Andrew Friedland • Rick Relyea
Environmental Science
FIRST EDITION
CHAPTER 5
Evolution of Biodiversity
© 2012 W. H. Freeman and Company

2. F. assafoetida – Dung of the Devil

3. Nature’s Pharmacy
Rosy periwinkle

4. Species Diversity
…in a healthy forest

5. Plantation -v- Forest

6. Ecosystem Diversity
Species Diversity
Genetic Diversity

7. Species: A population of organisms With shared characteristics
Capable of interbreeding, and
Producing fertile offspring
In nature

8. How diverse are insect populations in the rainforest?
What group of insects is most abundant?
Where do most insects reside within the rainforest?

10. Species Richness -v- Evenness

11. Derived Trait
Phylogenies are used to show how closely related different groups of animals are based upon their shared traits.

13. Environmental pressures affect phenotype

14. Artificial Selection

16. Principles of Natural Selection
A mechanism to explain how evolution works

17. Over-reproduction
Producing more offspring than can possibly survive in nature Why would an organism waste all of this energy? Because many will not survive, (life’s hard!!), having many offspring ensures that at least some will survive

18. Variation
Organisms have differences in the their phenotypes, their characteristics. We’re not all identical!!
Sources of variation:
mutation
meiosis:
Crossing over
Independent assortment
Sexual reproduction

19. Struggle for Survival Organisms must compete for limited resources
What do they compete for?
Food
Water
Mates
Territory
Shelter

20. Survival of the Fittest
Only those organisms best adapted to their environment can survive (and pass on their DNA!) What will happens to populations of organisms over time? A population becomes better suited to its environment.

21. What makes an organism/population/species fit?
Adaptation:
A structure, behavior or internal process that makes an organism better suited to its environment
Evolution:
Occurs to a population (species), not an individual

28. Hardy Weinberg Equation
p2 + 2pq + q2 = 1
What does this mean?
A population is comprised of the sum of its various genotypes, and this should remain constant.
But it doesn’t remain constant. Ever.
It does give us a baseline from which to evaluate change.
What factors cause the frequencies of genotypes to change?

35. Allopatric Speciation

36. PANGAEA
LAURASIA
120°
40°
80°
120°
120°
80°
120°
80°
80°
GONDWANALAND
135 million years ago
225 million years ago
NORTH AMERICA
EURASIA
AFRICA
120°
80°
120°
120° 0°
40°
120°
INDIA
SOUTH
AMERICA
AUSTRALIA
ANTARCTICA
65 million years ago
Present

38. Sympatric speciation through polyploidy

40. Ability of a Species to Adapt to Change

41. Ability of a Species to Adapt to Change

42. Ability of a Species to Adapt to Change

43. Ability of a Species to Adapt to Change
……R and K strategists, coming soon

44. Range of Tolerance for a Species
Just one of many factors

45. Is it better to be a generalist?

46. …or a specialist?

47. How do we collect this data?

48. Predicting Future Species’ Distribution

49. The Fossil Record

50. Mass Extinctions & Explosions of Life

52. An FRQ, to ponder.