Evolution

1. Evolution

2. History of Evolution Important Players

3. James Hutton • Published studies in 1785 • Geologist • Theory of Uniformity- the earth was created by the same forces that are in existence today (plate tectonics) • Before Hutton, world was thought to be 6000 years old and formed by catastrophic events, not geological ones • His research supported that the Earth to be millions of years old

4. Thomas Malthus • Worked with human population studies • Observed that plants and animals reproduce at a greater rate than their ability for survival, creating competition within a species • Important to Wallace and Darwin’s theory

5. Jean-Baptiste Lamarck • 1809- 1st to develop a scientific theory of evolution known as Theory of inheritance of acquired characteristics: • Organisms developed new organs or modified old ones to meet environmental challenges • Working toward perfection- more complex, more perfect • Selective use or disuse would alter the size or shape of organs or structures passed to offspring

6. Examples Larmarck Observed • Long Neck giraffes - short neck giraffes that strained to reach higher branches would grow longer necks • Fiddler crabs large claw (male) -developed one larger front claw because it used to claw often to attract mates and ward off predators

7. Lamarck’s Theory Proven to be False • Change DNA by usage of the structures (BOGUS! Mendel was not yet born so little was known about genetics). Think of body building and passing that on to your offspring • No extinction of species, just changed into other organisms • Lower order organisms were spontaneously created to fill the void (nothing was due to chance).

8. Alfred Wallace • 1850’s • Naturalist • Developed a theory similar to Darwin’s • His essay to Darwin motivated Darwin to publish the book, On the Origin of Species.

9. Charles Darwin • 1830’s • Known as the “Father of Evolution” • Naturalist on the HMS Beagle (shipping vessel) collecting specimens of flora and fauna and created detailed written observations • Inspired by the biological diversity of the Galapagos Islands

11. Voyage of the Beagle • 5 year voyage began in 1831 • Only 5 weeks spent on the Galapagos Islands • Found endemic species • Saw variations of organisms on the different islands (thought that this could be modification due to environment)

13. Evolution Terms • Evolution – descent with modification / changes over time • Adaptation – inherited characteristic that may increase organisms chance of survival • Speciation – formation of new species • Species – group of similar organisms that can breed in nature and reproduce fertile offspring.

14. Evolution Terms • Homologous Structures – similar structures found in different organisms that serve different functions • Analogous Structures – structures that are different in form but have the same function.

15. Evidence of Evolution • Biochemistry – DNA and amino acids • Embryological Development • Fossil Record • Morphology – form and structure of organisms without consideration of function • Vestigial Organs - structure that no longer serves a useful function in an organism (ex. Human appendix)

17. Fossils • Age of fossils can be determined by: 1.analyzing its position in the sedimentary layers 2. Radioactive dating

18. Archaeopteryx – earliest bird (had reptilian and bird –like characteristics

19. Vestigial Organ

20. 4 Mechanisms for Change • Natural Selection • Mutation • Migration • Genetic Drift

21. Why are brown beetles more prevalent in a population? Each of the 4 mechanisms will change the gene pool frequency

22. Natural Selection • Process in which organisms with favorable traits (traits well suited for their environment) are more likely to survive and reproduce Survival of the Fittest or the “Sexiest”

23. Imagine that green beetles are easier for birds to spot (and hence, eat). Brown beetles are a little more likely to survive to produce offspring. They pass their genes for brown coloration on to their offspring. So in the next generation, brown beetles are more common than in the previous generation.

24. Mutation • change in DNA sequence that causes a variation in the offspring • A mutation could cause parents with genes for bright green coloration to have offspring with a gene for brown coloration. This would make the genes for brown beetles more frequent in the population.

25. Migration • Some individuals from a population of brown beetles might have joined a population of green beetles. That would make the genes for brown beetles more frequent in the green beetle population.

26. Genetic Drift • “Pure chance” • Imagine that in one generation, two brown beetles happened to have four offspring survive to reproduce. • Several green beetles were killed when someone stepped on them and had no offspring.

27. Patterns of Evolution • Founder Effect • Speciation • Punctuated equilibrium • Adaptive/Divergent Radiation • Convergent evolution • Coevolution

28. Founder Effect • Organisms become separated or isolated and the gene frequency changes • Founding organisms arrived on different islands of the Galapagos and due to the different availability of food slowly changed the gene pool of the population.

29. Speciation • Reproductive isolation causes new species to form • Types of Isolation: • Behavioral • Geographic • Temporal

30. Punctuated Equilibrium • Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change Hardy-Weinburg Theory • No movement in or out of the population • No mutations • No natural selection forces

31. Evolution Terms • Adaptive/Divergent Radiation – process that causes a single species to evolve into new forms and eventually new species • Homologous Structures

32. Evolution Terms • Convergent Radiation process by which unrelated organisms come to resemble one another because of similar environment • Analogous structures Cactus and spurge are another example of convergent evolution.

33. Coevolution • Two species that evolve in harmony with one another because of the close interaction they have with each other