1 / 27

Evolution

Evolution. What is Evolution?. evolution - changes in populations over time modern evolutionary theory is based on the ideas of Charles Darwin. Darwin’s Theory. Organisms have changed over time; the ones living today are different from those that lived in the past.

shika
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

  2. What is Evolution? • evolution- changes in populations over time • modern evolutionary theory is based on the ideas of Charles Darwin

  3. Darwin’s Theory • Organisms have changed over time; the ones living today are different from those that lived in the past. • Organisms are derived from common ancestors through branching; populations split into different species.

  4. Change is gradual and slow. • The mechanism for evolutionary change is natural selection.

  5. What is natural selection? • organisms compete for food, mates, space, etc. • traits of organisms vary • organisms with less desirable traits are less likely to survive and reproduce

  6. natural selection- occurs when organisms with favorable variations survive, reproduce, and pass their variations to the next generation

  7. artificial selection- breeding organisms with specific traits in order to produce offspring with those traits • dog breeds

  8. Evidence for Evolution-Adaptations • adaptation- any structure, behavior, or internal process that aids an organism’s chances of survival

  9. according to Darwin’s theory, adaptations develop over many generations • most structural adaptations develop over millions of years • examples- thorns, porcupine quills, teeth, claws, coloring

  10. mimicry- adaptation that enables one species to resemble another species • camouflage- adaptation that enables species to blend with their surroundings

  11. MONARCH VICEROY CORAL SNAKE MILK SNAKE

  12. physiological adaptations- changes in an organism’s metabolic processes • can evolve over a very short period of time • Examples • bacterial resistance to antibiotics • insects/weeds resistance to pesticides

  13. Fossils • fossil- physical evidence of an organism that lived long ago; appear in rocks, amber, and ice • fossil records are incomplete • scientists use the fossils they have to understand how groups evolved

  14. HOMINID SKULLS

  15. Anatomy • anatomy- location/appearance of body features • used as evidence that organisms evolved from a common ancestor

  16. homologous structures- structural features with a common evolutionary origin; can be similar in arrangement, function, or both • Example- the forelimb bones of whales, crocs, and birds are arranged in a similar way

  17. analogous structures- body parts or organisms that are similar in function but do not have a common evolutionary origin • Example- bird and butterfly wings

  18. vestigial structure- a structure in a present-day organism that no longer serves its original purpose, but was once useful to an ancestor • Examples- eyes of blind mole-rats, pelvic bones in baleen whales

  19. WHALE EVOLUTION

  20. BOA HUMAN

  21. Embryology • embryo- the earliest stage of growth and development in plants and animals • shared features in young embryos suggest evolution from a common ancestor

  22. Biochemistry • all living things are biochemically similar- made of the same stuff • Examples • DNA • ATP • cellular respiration/metabolism • mitochondria • plasma membranes • similarities in gene sequences can determine relatedness • chimpanzees are the closest living species to humans- 98% of their genes match ours

More Related