1 / 29

Evolution

Evolution. The Earth has been home to living things for about 3.8 billion years. Evidence. Fossils – the remains of once living organisms preserved in the Earth Types of fossils: Hard Body parts (such as bones, teeth, shells ) Imprints in Sedimentary Rock. W hich rock layer is the oldest?.

frieda
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 The Earth has been home to living things for about 3.8 billion years.

  2. Evidence • Fossils– the remains of once living organisms preserved in the Earth • Types of fossils: • Hard Body parts (such as bones, teeth, shells) • Imprints in Sedimentary Rock

  3. Which rock layer is the oldest?

  4. Mass Extinction • A period when large number of species became extinct at nearly the same time. • Permian Era- 225 mya: 90% of marine life when extinct • Cretaceous Era – 65 mya. Disappearance of dinosaurs

  5. How did new species arise on Earth? • Evolution- the change of a species over a LONG period of time.

  6. We know today that the changes arise from genetic mutations or variations that are passed down from generation to generation. • But where did this idea come from?

  7. 2 Theories of Evolution • 1. Theory of Acquired Characteristics • The idea that a species can “get” a trait by passing it on to the next generation. • Lamarck!

  8. Lamarck thought that if an animal acquired a characteristic during its lifetime, it could pass it onto its offspring.

  9. Charles Darwin • Naturalists who published The Origin of Species after studying a variety of species on his voyage.

  10. 2. Theory of Natural Selection • Natural Selection – the best trait that is suited for the environment will allow a species to survive and reproduce at a higher rate

  11. The Beagle

  12. Darwin’s Voyage1831-1836

  13. The Galapagos Island (just read…) • Darwin was fascinated in particular by the land tortoises and marine iguanas in the Galápagos. • Giant tortoises varied in predictable ways from one island to another. • The shape of a tortoise's shell could be used to identify which island a particular tortoise inhabited.

  14. The Galapagos Islands • Darwin collected the preserved remains of ancient organisms, called fossils. • Some of those fossils resembled organisms that were still alive today.

  15. The Journey Home • Darwin Observed that characteristics of many plants and animals vary greatly among the islands • Hypothesis: Separate species may have arose from an original ancestor

  16. Discovery of Genetics?!?!? • From 1856-63, a monk called Gregor • Mendel cultivated 29,000 pea plants • to investigate how evolution worked • i.e., how characteristics were passed • down the generations. • He figured out the basic principles of • genetics. He showed that offspring • received characteristics from both • parents, but only the dominant • characteristic trait was expressed. • Mendel’s work only came to light in • 1900, long after his death Mendel and his peas

  17. Four Factors that support Natural Selection • Adaptation- trait that allows species to survive and reproduce in a particular environment. • Selection– organisms with particular adaptations are most likely to survive and reproduce. • Overproduction– an abundance of offspring are produced, but not all survive. • Variation- results from mutations and increases the variety of traits in a species

  18. Evolution by Natural Selection • The Struggle for Existence-members of each species have to compete for food, shelter, other life necessities • Survival of the Fittest-Some individuals better suited for the environment • Where food was limited, competition meant that only the fittest would survive. • This would lead to the natural selection of the best adapted individuals and eventually the evolution of a new species.

  19. Welcome to Shark Tank! • Which shark is the fittest?

  20. Natural Selection • Over time, natural selection results in changes in inherited characteristics of a population. These changes increase a species fitness in its environment

  21. Evidence of Evolution • Fossilized Evidence • Similarities in Early Embryonic Development • Geographic Distribution of Living Things • Homologous Body Structures

  22. FossilizedEvidence

  23. Similarities in Early Development(look @ colorsheet)

  24. Evidence for Evolution • Vestigial organs - physical structures that were fully developed and functional in an ancestral group of organisms, but is reduced and unused in the later species. • So basically… organs that serve no useful function in an organism • i.e.) appendix, miniature legs, arms

  25. Homologous Structures • Similar structures that are related species have inherited from a common ancestor. • Ex- the bones in a bird’s wing, dolphin’s flipper, dog’s leg, human’s arm

  26. GENETIC EVIDENCE!!!

  27. Works Cited • http://www.pbs.org/wgbh/evolution/change/family/index.html • http://www.ucmp.berkeley.edu/education/explorations/tours/Trex/index.html • What did T-Rex taste like? • http://www.the-brights.net/images/TeacherRequest%20Form.pdf • http://www.nclark.net/Evolution#Activities

  28. Activity Natural Selection in the Peppered Moth

More Related