1 / 23

Evolution

Evolution. By Diana L. Duckworth Rustburg High School Campbell County. Two Separate Issues. Does evolution occur? Immutability of species or transmutation of species Did all life originate from one common ancestor? If evolution occurs, how does it occur?. Before Origin of Species.

kioko
Download Presentation

Evolution

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.

E N D

Presentation Transcript

  1. Evolution By Diana L. Duckworth Rustburg High School Campbell County

  2. Two Separate Issues • Does evolution occur? • Immutability of species or transmutation of species • Did all life originate from one common ancestor? • If evolution occurs, how does it occur?

  3. Before Origin of Species • Erasmus Darwin – physician, poet • All life descended from single filament • Grew in complexity; capacity for self improvement; improvements handed down to offspring • Darwin’s grandfather http://a-evolucao-de-darwin.weblog.com.pt/arquivo/2008/02/concurso_erasmus_darwin

  4. Lamarck -Philosophie Zoologique • French – translation problems • After career of 30 years abruptly became an evolutionist (1800) • Spontaneous generation • Tend toward complexity • Explanation: • Pressures from environment – new needs • Use certain organs more; grow larger • Acquired characteristics are heritable http://bio.research.ucsc.edu/people/bernardi/Marina/public_html/Bio175/Bio175Website/Index.html

  5. Important Influences on C. Darwin • Malthus – populations grow exponentially; competition for food so not all survive • Charles Lyell – professor at Cambridge; lifelong friend & advisor • First textbook of geology • Propounded uniformitarian principle instead of catastrophism • Earth history built up through small, gradual changes • Earth is very old http://www.lakesideschool.org/studentweb/worldhistory/modernworld/ThomasRobertMalthusessay.htm http://io.uwinnipeg.ca/~simmons/16cm05/1116/16evolut.htm

  6. Charles Darwin • Young man – without real direction • Obtained position on HMS Beagle as companion to captain • Voyage 1831 – 1836 • Started out believing common view – species are immutable http://nayagam.wordpress.com/2006/02/

  7. Changing Ideas • During voyage, Darwin became convinced that species do change over time – the transmutability of species • Fossil evidence from South America • Similarity of species in Galapagos to those on South American mainland http://www.geol.umd.edu/~jmerck/galsite/research/projects/hayeslip/darwin.html http://www.mccullagh.org/image/d30-3/iguana-closeup.html

  8. Galapagos • Chance remark by governor of Galapagos – • Can tell what island a tortoise comes from by the shape of his shell

  9. Mockingbirds • Darwin recognized mockingbirds • Labeled with island of origin – • Gave them to bird expert, John Gould, on his return to London • Gould found 3 speices among specimens • Each species from a different island!

  10. http://www.hiltonpond.org/ThisWeek020501.html http://www.birddigiscoping.com/2005_10_01_archive.html http://costaricaphoto.wordpress.com/ Collected a bunch of little brown birds; based on beaks, he thought they were a mix of grosbeaks, wrens, finches & orioles; did not label collection location. http://www.avianweb.com/finchspecies.htm

  11. “Darwin’s” Finches • Gave them to John Gould • All finches – 13 species!! • Now Darwin wondered • how could 13 different, but closely related species arrive in the Galapagos? • His answer • one arrived & evolved into 13 species

  12. http://www.greenclub.bc.ca/Green_Club_Activity/GVRD_Parks_Events/gvrd_parks_events.htmhttp://www.greenclub.bc.ca/Green_Club_Activity/GVRD_Parks_Events/gvrd_parks_events.htm

  13. Insights led to theory • Idea was fully formed by 1838 • Filled series of notebooks which contain every important concept in evolution • Done by 1844 • Yet he did not publish until 1859 http://www.shimer.edu/admissions/dialectic-natural-sciences.cfm

  14. Why the delay? • Darwin had very poor health. Long periods of inactivity. • Knew dramatic impact of his ideas & wanted to support them with more data. • Began work on barnacle classification which took 10 years & other experiments to bolster his theory. • Other considerations: • Impact on his marriage since his wife was pious Christian, distractions & responsibilities of family & community life; political climate (he was establishment, idea might encourage radicalism); did he not want to offend his friends in clergy?

  15. What prompted the publication • Competition from a young naturalist working in East Indies • Alfred Russell Wallace • Independently happened on the same idea, even calling it “natural selection” • Observed the change from Australian to Asian species in the Indonesian Islands • Darwin simply did not want to be scooped! His ego would not allow it! http://www.thebeagleproject.com/2007/03/i-am-afraid-ships-on-fire-or-why-this.html

  16. Wallace Line http://people.eku.edu/ritchisong/RITCHISO/birdbiogeography.html

  17. On the Origin of Species • Took Darwin one year to complete and publish manuscript. He could not include all of the data he had amassed in intervening years. • First half of Origin he answered the question “HOW?” • Natural Selection • Second half he presented arguments from four areas of research that supported the concept of transmutation of species & that all life had evolved from a common ancestor. • Biogeography; comparative anatomy; embryology; & paleontology (fossils)

  18. Natural Selection • Populations of a species have variability in traits & these traits are heritable. • A trait may convey a survival advantage on the individual possessing it. • These individuals survive to reproduce in greater numbers. • Advantageous trait is passed on to their offspring. • Advantageous trait increases in population.

  19. Speciation • Isolation of a population is required for natural selection to produce another species. • May be geographic isolation. • Changes in the environment produce the selective force which causes natural selection.

  20. From 1859 to 1882 • Darwin was already well known in scientific circles for his body of work • This book made him famous at all levels of society and on all continents • It quickly sold out & there were 5 more editions • Subject of much rumor; not everyone read the book & just over simplified ideas & distorted them.

  21. Single greatest misconception: • Man evolved from monkeys…. Man was not discussed in Origin but in a later book, The Descent of Man… • What Darwin said: • All life developed from a common ancestor – note that the word evolution does not appear in Origin • In other words, man and monkey had a common ancestor that was neither man, nor monkey

  22. Greatest Flaw • Darwin did not abandon some of the Lamarckian ideas • He did not know of the work of Gregor Mendel, so he did not know the reality of inheritance • Enamored of idea of use & disuse (use it or lose it) • Did not refute the idea of the inheritance of acquired traits.

  23. How does transmutation occur? • Natural Selection – survival of the fittest • Individuals with traits that give them an advantage in their environment will survive and reproduce, thus passing these advantageous traits on to the next generation. • Populations must have variable traits • These traits must be heritable

More Related