Evolution Standard: SB5d EQ: How does natural selection lead to a change in a species?

1. EvolutionStandard: SB5dEQ: How does natural selection lead to a change in a species? By: Amber Tharpe

2. Evolution • Change in a species over time • “descent with modification” • Theory- subject to change, but much evidence to support it • Does not mean humans came from monkeys • Unites many scientific fields

3. Lamarck • Inheritance of acquired traits • An organism could acquire characteristics during its life and pass them on to offspring • Ex: giraffes stretched their necks to reach food and passed the long neck trait to their offspring • Problem- can only pass heritable traits to offspring, not those acquired during life

5. Darwin • Naturalist on the Galapagos Islands- observed many species • Darwinism- evolution by natural selection • Published Origin of Species in 1859 • Fitness- ability to survive and reproduce better than others

6. Extinction • When a species is forever wiped out from existence on earth • Ex: dinosaurs, dodos, wooly mammoths, saber-toothed tigers

7. Gradualism • Theory that biological change results from slow and steady changes over a long period of time • Small changes add up to large change over time • Evidence- Intermediate forms are found in the fossil record for some species • Darwin favored this theory

8. Punctuated Equilibrium • Biological change results from a quick, sporadic process over a short period of time • Mutations of a few genes result in the appearance of a new species • Evidence- gaps appear in the fossil record

9. Galapagos Islands

10. Darwin’s Finches • Noticed many different types of finches on the Galapagos Islands • The finches were all related- similar except for their beaks • Each beak was suited to its diet, the diets varied to the various habitats • The beaks were adapted to their habitat • Evidence of natural selection

12. Geographical Isolation • physical barriers that divide a population into 2 or more groups • Speciation • the rise of 2 or more species from 1 existing species

13. Lyell • Tectonic plate shifting • Land was once all connected as one continent, Pangea • Wallace • Came up with the theory of natural selection at the same time as Darwin • Mendel- late 1800’s • Genetics and heredity support theory of natural selection • Genes provided the missing link for how traits could pass from parent to offspring

14. Natural Selection • Aka. “Survival of the fittest” • Individuals with more favorable characteristics survive and reproduce better than others • Mechanism that causes evolution • Acts on phenotypes (physical traits), not genotypes

18. Steps of Natural Selection • Variation • Overproduction • Adaptation • Descent with Modification

19. Variation • Natural differences between individuals of a species • Overproduction • More offspring are produced than can survive • There are not enough resources, so there is competition for them • Adaptation • A certain feature that allows an individual to survive better and reproduce in its environment, so it is “naturally selected”

20. Descent with modification • When individuals with this adaptation survive and reproduce, they pass the genes for this trait to their offspring • The trait becomes more common in the population as long as it provides a benefit

21. Artificial Selection • Breeding • When humans decide what traits are favorable and select for them • Ex: toy, miniature, and teacup dogs

22. Fossils • Fossils provide evidence of organisms that once lived • Ex: Skeletons, bone fragments, footprints, ect • Form in wetlands or on the floor of bodies of water • Show changes in organisms over time • evidence of evolution • Paleontology- the study of fossils

25. Dating Fossils • Relative dating- • Deeper layers of rock are older, while those closer to the surface are younger • We use the placement of fossils in the layers to determine the approximate age the organism lived • Radiometric dating- • Use half-lives of radioactive isotopes found in the living organisms

26. Biogeography • The distribution of species on earth • Ex: don’t find the same exact species on an island and the mainland • Provides evidence for evolution • Characteristics of organisms are well-suited to their environment

27. Embryology • The structure of animals before birth • Many organisms are similar in appearance as embryos but are significantly different as adults • The sooner a characteristic appears in development, the older the trait is • The similarities provide evidence for evolution

29. Comparative Anatomy or Morphology • Homologous structures • Similar body parts that come from a common ancestor • Ex: fins of whales, wings of bats, and arms of humans • Analogous structures • Serve the same purpose, but not from a common ancestor • Ex: wings of insects, bats, and birds

30. Convergent evolution • Unrelated species become similar due to a similar environment • Ex: analogous structures • Divergent evolution • Related organisms become more and more different due to isolation • Ex: speciation

31. Homologous Structures

32. Analogous Structures

33. Comparative Anatomy or Morphology • Vestigial Organs • Structures that have no use • Remnants of structures that had a function in an earlier ancestor • Ex: wings on flightless birds, appendix in humans

34. Biochemistry and Molecular Biology • Comparing DNA or proteins • Same 4 nucleotides make up DNA for all living things • Same 20 amino acids make up proteins for all living things • The more similar DNA or proteins, the more closely related 2 organisms are

35. Phylogenic Trees • Family trees that show evolutionary relationships • Can be made by examining evidence of evolution

36. Origins of Life • Life on earth began 4.5 billion years ago • Water was present and prokaryotes were the first organisms to live • Eukaryotes came from small prokaryotes living symbiotically in larger prokaryotes • endosymbiosis- mitochondria and chloroplasts were formed this way • Sexual reproduction gave greater diversity

37. Geologic Time Scale • Precambrian- bacteria lived • Cambrian explosion- time when a huge diversity of animal species evolved • Paleozoic Era- invertebrates, reptiles, and seed plants lived • Mesozoic Era- dinosaurs, birds, flowering plants lived • Cenozoic Era- Mammals and humans lived

38. Geologic Time Scale • Units of time from largest to smallest • Era • Period • Epoch

39. Coevolution • When a species evolves in response to changes in another species • Ex: plants and insects

40. Biological Resistance • Living organisms over time become resistant to substances made to kill them • Ex: antibiotics, pesticides, herbicides, ect • Due to natural selection