V. Diversity

1. V. Diversity A. Age of Exploration (15th – 17th Century) 1. Modern estimates: 5-50 million species 2. Problems • Not enough room on the Ark • Extinction • Organization?

2. V. Diversity B. God’s organizer: Carl von Linne (Linnaeus) (1707 – 1778) 1. System of Nature (1735) • 4400 species of animals/ 7700 species of plants • Binomial nomenclature • Genus and species: Pan paniscus • Bonobos • Homo sapiens • Mammalia

3. V. Diversity B. God’s organizer: Carl von Linne (Linnaeus) (1707 – 1778) 2. Taxonomic categories • Gorillas • Chimps • Orangutans • controversy

4. V. Diversity • Linnaeus: taxa only real in the mind of God • Idealized forms (type species) • Darwin: • Evidence of common ancestry • Works well with evolutionary • scheme, not the Ladder of Life • Nested hierarchies family genera • Genetic connection species • DNA-DNA • hybridization • DNA profiling 3. Linnaeus remained creationist until late in life

5. V. Diversity C. Richard Owen (1804 – 1892) 1. Archetypes (body plans) • Homology : same structures modified for different purposes 2. Owen: example of argument from design 3. Darwin: evidence of common ancestry

6. VI. Before Darwin A. Non-evolutionary thought 1. The Greeks • Plato: idealized forms are templates for imperfect • replicas • Aristotle • Life is one big continuum • Ladder of Life dominant until Darwin 2. The Bible • All life created in one week, 4004 BC

7. VI. Before Darwin A. Non-evolutionary thought 3. Natural Theology • As far back as Galen • William Paley (1743 – 1805) • Argument from design • Revival in 19th Century • Evolution’s biggest competitor

8. VI. Before Darwin A. Non-evolutionary thought 3. Natural Theology • Mid 18th Century (Enlightenment) looks for natural • (materialistic) causes • David Hume (1711 – 1776) • Dialogues Concerning Natural Religion (1796) • False analogy: many ways in which living • things are not like machines • We don’t know the nature of the designer(s) • Much in the world that is imperfect and unjust • Our knowledge of the Universe is limited “No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish. “

9. VI. Before Darwin B. Evolutionary thoughts 1. Comte de Buffon (1707 – 1788) • All “species” from family ancestors • Species not real but rather varieties evolved from • original form • Ancestral forms from spontaneous generation • First episode on primeval hot earth; went extinct • Second episode gave rise to ancestors of modern forms

10. VI. Before Darwin B. Evolutionary thoughts 2. Erasmus Darwin (1731 – 1802) • Single common ancestor • Competition • Sexual selection “Organic life beneath the shoreless wavesWas born and nurs'd in ocean's pearly caves;First forms minute, unseen by spheric glass,Move on the mud, or pierce the watery mass;These, as successive generations bloom,New powers acquire and larger limbs assume;Whence countless groups of vegetation spring,And breathing realms of fin and feet and wing.” Temple of Nature (1802)

11. VI. Before Darwin B. Evolutionary thoughts 3. Jean-Baptiste Lamarck (1744 – 1829) • Spontaneous generation starts • the evolutionary process • Progressive evolution with each generation becoming more complex • Linear scale with humans the ultimate goal • No gaps, only missing data • No extinction (missing fossil not yet found) • Process that distorts progression • Inheritance of acquired characteristics • Use and disuse of parts

12. VI. Before Darwin B. Evolutionary thoughts 4. Robert Chambers (1802 – 1871) • Vestiges of Creation (1844) • Progressive evolution • Embryo occasionally jumps to another form • Popular with the middle classes • Not popular with conservatives or scientists • Legacy • Evolution equated with progress (popular idea) • Starts debates over evolution • Uproar over Vestiges makes Darwin cautious

13. VII. Charles Darwin (1809 -1882) A. Life

14. VII. Charles Darwin (1809 -1882) B. Voyage of the Beagle (1831 -1836)

15. B. Voyage of the Beagle (1831 -1836) 1. Observations in South America and Australia Greater Rhea Lesser Rhea Sloths • marsupials

16. B. Voyage of the Beagle (1831 -1836) 2. Observations in the Galapagos Islands “animals and plants of a region are most closely related to those of nearby regions and reflect the history of the region”

17. C. The Discovery of Natural Selection 1. Evidence from travels 2. Barnacles 3. Artificial Selection 4. Malthus (1766 - 1834) • Population growth will always • outpace food production • Exponential vs. geometric

18. C. The Discovery of Natural Selection 5. Darwin’s eureka moment (July 1837) “ it was like admitting murder” 6. The long interlude (20 years!) • Other commitments • Confidence • Illness • Concern 7. Letter from Alfred Russell Wallace (1823 – 1913) • 1858

19. D. On the Origin of Species (1859) 1. Contents and evidence • Artificial selection Zea mays • Teosinte maize

20. D. On the Origin of Species (1859) 1. Evidence • Taxonomy = common ancestry Neanderthals • Fossil record Archaeopteryx

21. Biogeography “animals and plants of a region are most closely related to those of nearby regions and reflect the history of the region” Cactus Spurge Convergent evolution

22. Homology • Comparative anatomy • analogy

23. Homology Embryonic development: • structure and pathways • Pharyngeal pouches Gills Eustachian tubes

24. Dandelion Imperfections • Vestigial structures Pollen Wisdom teeth Goosebumps Wings of flightless birds Appendix Whale pelvis Cravings: sugar and fat

25. Evolution is a tinkerer. Imperfections Our textbooks like to illustrate evolution with examples of optimal design ,,,. But ideal design is a lousy argument for Evolution ,,,. Odd arrangements and funny solutions are the proof of evolution--paths that a sensible god would never tread but that a natural process, constrained by history, follows perforce.   --Stephen Jay Gould

26. 2. Challenges to the Theory Time Variation The fossil record

27. Fossil record • Fish to amphibian • Ape to human • Whale evolution • Bird evolution • Caveat!

28. Theory: a well documented, explanatory principle 3. Natural Selection • All populations have the potential to overproduce 2. Because of limited resources, no population increases indefinitely 3. Therefore, individuals must compete for limited resources 4. Individuals with variations that allow them to compete successfully for resources will survive and reproduce at a higher frequency 5. If variations (4) are heritable, individuals with those variations will exist at a higher frequency in future generations

29. 3. Natural Selection Differential reproductive success ‘survival of the fittest’ ‘Descent with modification’ Bonobos

30. 4. The Fact and the Theory of Evolution

31. 5. The Uniqueness of Darwin’s Theory No direction Adaptation to local environments

32. 5. The Uniqueness of Darwin’s Theory Population thinking

33. 5. The Uniqueness of Darwin’s Theory Common ancestry ‘There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.’ Charles Darwin, 1859.

34. 6. The Reaction to Darwin’s Theory • Evolution • Natural Selection • Problems: • No mechanism to • create diversity • No progress

35. 7. Evolution:the Organizing Principle of Biology Evolution explains why organisms are similar (common ancestry) and why they are different (adaptation).