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Evolution and Change

Evolution and Change. Chapter Thirteen: Evolution. 13.1 Evidence for Evolution 13.2 How Evolution Works 13.3 Natural Selection. 13.1 Evidence for Evolution. An adaptation is an inherited trait that helps an organism survive.

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Evolution and Change

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  1. Evolution and Change

  2. Chapter Thirteen: Evolution • 13.1 Evidence for Evolution • 13.2 How Evolution Works • 13.3 Natural Selection

  3. 13.1 Evidence for Evolution • An adaptationis an inherited trait that helps an organism survive. • Adaptations include body structures that help an organism feed, move around, and protect itself.

  4. 13.1 Evidence for Evolution • Evolutionis the process of how organisms acquire adaptations over time. Eohippus is an ancestor of what modern animal?

  5. 13.1 Evolution is a branching process • Diversity means variety. • Scientists hypothesize that all life forms evolved from a common ancestor and new species branch off from earlier species. • Similarities among all cells support the hypothesis that all life evolved from a common ancestor. • All cells have a similar cell membrane. • Many cells have the same type of cellular respiration. • All cells have DNA as their hereditary material.

  6. 13.1 Evolution is a branching process • An ancestoris an organism from which others have descended. • A cladogramdisplays evolutionary relationships among living species and their ancestors.

  7. 13.1 Lines of Evidence • Many lines of evidence provide the basis for the theory of evolution. These include: • comparative anatomy • DNA analysis • fossil record

  8. 13.1 Lines of Evidence • Comparative anatomyis the study of anatomical similarities and differences among species. • What does your arm have in common with the wing of a bird, the flipper of a porpoise, and the forelimb of an elephant? • Analogous structuresserve the same function but come from different origins. • Homologous structureshave a common origin, but do not necessarily perform the same function.

  9. 13.1 Lines of Evidence • Vertebratesare animals with a backbone. • Comparative anatomists have discovered similarities in embryos of vertebrates. • Adult vertebrates also share many similarities in their skeletons and muscles.

  10. 13.1 Lines of Evidence • Species that share more similarities in their DNA base sequences are more closely related than those that share fewer similarities.

  11. 13.1 Fossils • A fossilis a remnant or trace of an organism from the past, such as a skeleton or leaf imprint, embedded and preserved in Earth’s crust.

  12. 13.1 Fossil Record • Fossils found in the upper (newer) sedimentary layers more closely resemble present-day organisms than fossils found in deeper (older) layers.

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