1 / 30


Evolution. By: Andrew George!!!!!! YAY!!!!!. Evolution and the Nature of Science . Evolution is the theory that organisms change over time as a result of natural selection Scientists estimate that the first fish-to-land transitional animals existed 375 million years ago

Download Presentation


An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. Evolution By: Andrew George!!!!!! YAY!!!!!

  2. Evolution and the Nature of Science • Evolution is the theory that organisms change over time as a result of natural selection • Scientists estimate that the first fish-to-land transitional animals existed 375 million years ago • Paleontologists found fossils with primitive lungs as well as gills • In Canada a scientific expedition discovered the Tiktaalik which was a transitional animal

  3. Cont’d • This fish was found in Nunavut, near the Arctic circle in northern Canada • Evolution helps to understand how things are related • Differences in organisms genetics and experiences causes natural selection.

  4. Cont’d • When SARS broke out in China the virus was found to be evolved from a known type. • Antibiotics and bacteria • Guppies in streams are bigger • Guppies in rivers are smaller • Incremental evolution takes a long period of time. (subgroups & separation)

  5. Cont’d • Speciation can be the result of incremental evolution • Turtles have amniotic eggs • Reptiles split into dinosaurs and birds • Transition from reptiles to mammals showed larger brains, specialized organs, and movement of limbs under the body.

  6. Cont’d • For thousands of years people have been harvesting crops. By selecting the best grain to replant they modified the genetic structure of the plants • (artificial selection)

  7. Cont’d • Theory or fact? • Theory refers to a comprehensive explanation that is supported by a vast body of evidence • Fact is an observation, measurement, or other form of evidence

  8. Cont’d • Positions on Evolution are scientism, deism, and theism • Scientism- science is everything • Deism- God made it but doesn’t mess with it now • Theism- God made it and is still changing things around

  9. The Rise of Evolutionary Biology • “Nothing in biology maks sense except in the light of evolution” (Theodosius Dobzhansky) • “change over time via descent with modification” (Harrison, 2001) • The woodpecker was one of Darwin’s favorite examples of adaptation • (beak, tail, feet)

  10. Cont’d • The stages of evolution • Evolutionary and non-Evolutionary ideas before Darwin • Darwin’s theory(1859) • The eclipse of Darwin(1880-1920) • The modern synthesis (1920s to 1950s)

  11. Cont’d • Species fixity was a staple of Darwin’s time • Darwin’s grandfather Erasmus Darwin also discussed evolution • John Baptiste Lamarck and his theory of transformism

  12. Cont’d • Lamarck’s thoery • An internal force caused offspring to be slightly different from the parents • Inheritance of acquired characteristics also changed offspring (giraffes)

  13. Cont’d • Lamarck was wrong • He published Philosophie Zoologique • Georges Cuvier began the study of taxonomy • His major groups though modified are used today • Contrary to Lamarck he believed that species could go extinct

  14. Cont’d • Darwin traveled aboard a ship named the Beagle(1832-1837) • His father was a doctor • His father in law controlled the Wedgwood china business • Darwin did not label which island his various species came from

  15. Cont’d • Alfred Russel Wallace had arrived at a very similar idea to Darwin’s natural selection • Both ideas were announced at the Linnaean Society in London (1858) • After that Darwin wrote “On the Origin of Species”

  16. Cont’d • In Darwin’s theory evolution is not inherently or automatically progressive • There is not inherent tendency to rise to a higher form

  17. Cont’d • One objection to Darwin’s theory was that it lacked a good theory of heredity • “blending” • Red and white couple • Lamarckian theory was most popular theory of heredity

  18. Cont’d • German Biologist August Weismann produced strong evidence and theoretical arguments that acquired characteristics are not inherited • Erik Nordenskiold wrote “An influential history of biology” that questioned Darwin

  19. Cont’d • Gregor Mendel’s work was rediscovered • Mendelism became the generally accepted theory of heredity since the 1920’s • Early mendelians opposed Darwin’s theory of natural selection • They supported the theory that macromutations caused evolution

  20. Cont’d • The synthesis of Darwin’s thoery of natural selection with the Mendelian theory of heredity is known as neo-Darwinism • “The variation of Animals in Nature” was written by G.C. Robson and O.W. Richards • They accepted neither Mendelism or Darwinism • Argued that species are non-adaptive and have nothing to do with natural selection

  21. Cont’d • “The Material Basis of Evolution”, argued that speciation was produced by macromutations and not small variations • The changes in gene frequencies within a gene pool is evolution • Orthogenesis is straight line vs tree

  22. Summary of evolution • Evolution means decent with modification (tree) • Living things possess adaptations to their natural environment • Evolution was discussed prior to Darwin but fixity of species was the prevalent thought

  23. Summary Cont’d • Darwin explains change and adaptation through natural selection • Darwin’s peers accepted his idea of evolution but not his theory of natural selection • Darwin lacked a theory of heredity, Mendel’s work supported his later

  24. Summary Cont’d • Fisher, Haldane, and Wright demonstrated that Mendelian heredity and natural selection are compatible(neo-darwinism) • Neo-Darwinism spread through all areas of biology in the 1930’s and 40’s

  25. The Development of Evolutionary Theory • Greek Philosopher Anaxiamander • Roman philosopher Lucretius • They coined the concept that all living things were related and had changed over time • Carl Linn set up the hierarchical classification of animals

  26. Cont’d • Linnaean Structure was that each species or taxon belonged to a higher category • Georges-Luis Leclerc, Comte de Buffon proposed that species could change during the 18th century in a 44 volume history of all (then) known animals and plants

  27. Cont’d • William Smith developed the Principle of Biological Succession • Each period of earth history has it’s own fossil layer • Father of Stratigraphy

  28. Cont’d • Abraham Gottlob Werner and Baron Georges Cuvier were proponents of catastrophism • Proposed that there had been several creations and catastrophes in the history of earth • Only bacteria are able to incorporate non-genetic traits

  29. Darwin’s Theory • Adaptation: all organisms adapt to their environments • Variation: all organisms are variable in their traits • All organisms tend to over reproduce • Some organisms reproduce more that others (natural selection)

  30. Wallace-Darwin Theory • Individuals have different successes in reproducing • Left unchecked population tends to expand exponentially • Organisms best able to survive and reproduce will leave more offspring • Genes frequencies changing in the gene pool will cause the phenotype to change

More Related