1. 1 Campbell et al. Chpt. 24 The Origin of Species

2. 2 leads to changes Microevolution leads to changes within populations within populations Macroevolution leads to great phenotypic changes resulting in distinctive lineages (e.g. species)

3. 3 Diversity of life What is a species? How does speciation occur? Rate of evolution

4. 4 1. Diversity of Life

5. 5 Part of giant experiment called life 1. Diversity of Life Cambrian Explosion (Burgess shell)

6. 6 1. Diversity of Life Diversity increased over time…

7. 7 1. Diversity of Life … with some interuptions

8. 8 1. Diversity of Life

9. 9 Bushy tree Evolution does not follow an inbuilt direction!

10. 10 1. Diversity of Life Hobbits - human tree just got bushier still. Homo floresiensis from 18,000 years ago, 1m high

11. 11 1. Diversity of Life Species = basic unit

12. 12 1. Diversity of Life Species = basic unit Speciation - rise of new species Continuous lineage - information passed through genes

13. 13 1. Diversity of Life 1.4 million species described ca. 10 million estimated many extinct species (about 90% of all species that ever lived are extinct)

14. 14 1. Diversity of Life 1.4 million species described ca. 10 million estimated many extinct species Large diversity of species - speciation must be a common event Understanding how this diversity arose is a central question in evolutionary biology

15. 15 Diversity of life What is a species? How does speciation occur? Rate of evolution

16. 16 2. Species Concepts I. Morphological Species Concept Species are similar in their appearance

17. 17 2. Species Concepts I. Morphological Species Concept - sometimes hard to apply Two different speciesOne single species

18. 18 2. Species Concepts I. Morphological Species Concept - sometimes gets it wrong New Zealand moa (extinct): females much bigger than males

19. 19 2. Species Concepts II. Biological Species Concept Two individuals of the same species interbreed with another in the wild and produce viable and fertile young

20. 20 2. Species Concepts II. Biological Species Concept - problems Fossils - how do we know if they interbreed? Good species can sometimes produce hybrid Asexual organisms

21. 21 2. Species Concepts II. Biological Species Concept - problems

22. 22 2. Species Concepts III. Cohesion Species Concept Adaptive landscape

23. 23 2. Species Concepts IV. Phylogenetic Species Concept Species = lineage between successive speciation events

24. 24 Diversity of life What is a species? How does speciation occur? Rate of evolution

25. 25 3. Speciation Process of speciation Parent species I. Barrier 2 separate species III. Dont interbreed II. Diverge

26. 26 3. Speciation I. Establishing a barrier Geographical separation Breed at different times Different courtship display etc Species are prevented from mating with each other- pre-zygotic barriers

27. 27 3. Speciation II. Population divergence Can be caused by any of the 5 causes of evolution Example: Artificial selection of domesticated animals

28. 28 3. Speciation II. Population divergence Example: Ring species Herring/Lesser Black-backed Gull

29. 29 3. Speciation II. Population divergence Genetic subdivision Example: Mice on Madeira

30. 30 3. Speciation III. Sexual incompatibility Offspring from matings between groups are not viable or fertile - post-zygotic barriers

31. 31 1. Barrier 3. Speciation Example Picture-winged fruit fly (Rhagoletis)

32. 32 3. Speciation Example Picture-winged fruit fly (Rhagoletis) Witnessed speciation! 1. Barrier 2. Divergence 3. Dont interbreed

33. 33 Diversity of life What is a species? How does speciation occur? Rate of evolution

34. 34 4. Rate of Evolution Gradualism (Darwin) - steady accumulation of small changes over long periods of time Rapid bursts of fast changes Stasis - no changes over long periods of time

35. 35 4. Rate of Evolution Example: Radiolaria Punctuated Equilibrium (Eldrige & Gould) - long periods of stasis interrupted by short periods of rapid change

36. 36

37. 37 Can speciation events be replicated? Play again the tape THE END

38. 38 1. Diversity of Life

39. 39 2. Species Concepts

40. 40 4. Rate of Evolution Example: Radiation of Darwin Finches on Galapagos