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Biology 441 Lecture 2: 9/10/07

Biology 441 Lecture 2: 9/10/07. Last time: Course mechanics, What is animal behavior?, Why study animal behavior? This time: History and Review of Evolution (& things I forgot to say) Next time: Proximate and Ultimate causes of behavior. Introduction to Ethology: Historical Perspectives.

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Biology 441 Lecture 2: 9/10/07

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  1. Biology 441Lecture 2: 9/10/07 • Last time: Course mechanics, What is animal behavior?, Why study animal behavior? • This time: History and Review of Evolution (& things I forgot to say) • Next time: Proximate and Ultimate causes of behavior

  2. Introduction to Ethology: Historical Perspectives • When did the study of animal behavior emerge?

  3. Introduction to Ethology: Historical Perspectives • When did the study of animal behavior emerge? • As far back as recorded history!!! (cave paintings; petroglyphs) • Animals were sources of FOOD and FEAR

  4. Introduction to Ethology: Historical Perspectives • Aristotle (384-322 B.C.) • First written records of mutualism, tool use, and brood parasitism

  5. Introduction to Ethology: Historical Perspectives • Three advances • 1. New Detailed biological knowledge: studies in inheritance and genetics; Human anatomy: structure of nervous system and brain (Helmhotz 1850)

  6. Introduction to Ethology: Historical Perspectives • Three advances • 1. New Detailed biological knowledge • 2. The Origin of Species 1859 • Natural selection • Sexual selection

  7. Introduction to Ethology: Historical Perspectives • Three advances • 1. New Detailed biological knowledge • 2.Darwin: The Origin of Species 1859 • 3. Development of a comparative method

  8. Introduction to Ethology: Historical Perspectives • Darwin’s contributions: 3 other books • 1. Variation of animals and plants under domestication • Argues that artificial selection can act on behavior as well as morphology

  9. Introduction to Ethology: Historical Perspectives • Darwin’s contributions • 1. Variation of animals and plants under domestication • 2. Expression of the emotions in man and animals • Principle of servicable habits • Antithesis

  10. Introduction to Ethology: Historical Perspectives • Darwin’s contributions • 1. Variation of animals and plants under domestication • 2. Expression of the emotions in man and animals • 3. The descent of man • Similarity between human and primate expressions • Similar states of mind?

  11. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes’ Animal Intelligence • “mental continuity”

  12. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes’ Animal Intelligence • “mental continuity” • ANTHROPOMORPHISM

  13. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes • C. Lloyd Morgan • Law of Parsimony

  14. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes • C. Lloyd Morgan • Law of Parsimony “in no way may we interpret an action as an outcome of the exercise of a higher faculty if it can be attributed as the outcome of one that stands on a lower physical scale”

  15. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes • Conway Lloyd Morgan • James Watson & B.F. Skinner (“Skinner Box”) • Strictly objective view of behavior • All behavior can be explained by stimuli/response mechanisms & reinforcement • Ignored any higher mental processes, motivation, hormones, etc.

  16. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes • Conway Lloyd Morgan • James Watson & B.F. Skinner (“Skinner Box”) • Behaviorism • Considered sterile and divorced from reality

  17. Introduction to Ethology: Historical Perspectives • The Comparative Method • George Romanes • Conway Lloyd Morgan • James Watson & B.F. Skinner (“Skinner Box”) • Behaviorism • Considered sterile and divorced from reality “Give me a dozen healthy infants, well-formed, and my own specified World to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief and yes, even beggar-man and thief…”

  18. Introduction to Ethology: Historical Perspectives • Birth of Ethology (early 1900s) • Extensive observation of animals in their natural environments

  19. Introduction to Ethology: Historical Perspectives • Birth of Ethology (early 1900s) • Observation of natural behavior: First creation of ETHOGRAMS • Recognition of species-specific patterns • Questions as to how these patterns arise; what is the adaptive significance?

  20. Introduction to Ethology: Historical Perspectives • Birth of Ethology • Observation of natural behavior: ETHOGRAMS • Recognition of species specific patterns • 1940’s Konrad Lorenz & Niko Tinbergen (Fathers of Ethology)

  21. Introduction to Ethology: Historical Perspectives • Lorenz • Pioneered studies of genetically programmed behavior (instinct) • Concept of imprinting

  22. Introduction to Ethology: Historical Perspectives • Tinbergen • Field biology • Developed Ethology’s 4 areas of inquiry

  23. Introduction to Ethology • Aims and Methods of Ethology: 4 Areas • Causation

  24. Introduction to Ethology • Aims and Methods of Ethology: 4 Goals • Causation • Development

  25. Introduction to Ethology • Aims and Methods of Ethology: 4 Goals • Causation • Development • Function

  26. Introduction to Ethology • Aims and Methods of Ethology: 4 Goals • Causation • Development • Function • Evolution (Tinbergen 1963)

  27. Evolution: the Basics • What is Evolution?

  28. Evolution: the Basics • What is Evolution? • any change in allele (gene) frequencies in a population over time

  29. Evolution: The Basics • What is Evolution? • any change in allele (gene) frequencies in a population over time • What is a population? • A localized group of organisms which belong to the same species

  30. Evolution: The Basics • What is Evolution? • any change in allele (gene) frequencies in a population over time • What is a population? • A localized group of organisms which belong to the same species • What is a species? • A group of populations whose individuals have the potential to interbreed and produce fertile offspring in nature

  31. Evolution: The Basics • What is Evolution? • any change in allele (gene) frequencies in a population over time • What is an allele?

  32. Evolution: The Basics • What is Evolution? • any change in allele (gene) frequencies in a population over time • What is an allele? • A variant of a gene or trait

  33. Evolution: The Basics • Examples of variation in traits • Eye color (blue, brown, hazel, green) • Timing of shell-removal for black-headed gulls • (45, 50, 60 minutes after hatching etc.)

  34. Evolution: The Basics • If frequency of particular variants of traits changes over time = evolution

  35. Evolution: The Basics • Change happens, therefore Evolution is fact • I.e., Species change over time

  36. Evolution: The Basics • Change happens, therefore Evolution is fact • I.e., Species change over time • Details of how this change occurs is explained by Darwin’s Theory of Natural Selection

  37. Darwin & Natural Selection • Observation 1 • All species have great potential fertility • Observation 2 • Populations remain stable • Observation 3 • Environmental resources are limited

  38. Darwin & Natural Selection • Observation 1 • All species have great potential fertility • Observation 2 • Populations remain stable • Observation 3 • Environmental resources are limited • Inference 1 • struggle for existence

  39. Darwin & Natural Selection • Observation 4 • Individual variation exists in populations • Observation 5 • This variation is heritable

  40. Darwin & Natural Selection • Observation 4 • Individual variation exists in populations • Observation 5 • This variation is heritable • Inference 2 • Survival in the struggle for existence is not random • Inference 3 • This leads to gradual change in populations with the accumulation of favorable characteristics

  41. Example: Black headed gulls • Assume that black-headed gulls have not always removed eggshells • The 1st eggshell remover appeared (perhaps a genetic mutation altered the birds nervous system) • The egg remover had good nest success • The “egg removing gene” was passed on • Eggshell removing offspring produced more offspring • Now all remove eggshells

  42. Natural Selection • = the differential success in reproduction of variants in a population

  43. Natural Selection • Mechanism of adaptive evolution • Chance events produce variation • Natural selection favors some variants over others

  44. Natural Selection • Evolutionary fitness • Def. The relative contribution an individual makes to the gene pool of the next generation • = Success of an organism in producing progeny

  45. Natural Selection • Limitations (I.e., why we don’t see only ‘perfect’ organisms • History (constraints) • Adaptations are often compromises • Not all evolution is adaptive (e.g., inbreeding or chance) • Selection can only edit variations that exist • Environmental change

  46. Natural Selection: Types • Sexual Selection • Sexual dimorphism • Def. Distinction between the secondary sexual characteristics of males and females

  47. Natural Selection: Types • Sexual Selection • Sexual dimorphism • E.g., size, plumage, lion manes, antlers, etc.

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