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AIM. What is Evolution?. Evolutionary Theory. Process of change in species over a long time They are distinctly different from earlier forms. Proof of Evolution. Fossils provide clues to the history of earth’s organisms. Proof of Evolution. DNA Analysis (Gel Electrophoresis).

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  1. AIM What is Evolution?

  2. Evolutionary Theory • Process of change in species over a long time • They are distinctly different from earlier forms

  3. Proof of Evolution • Fossils provide clues to the history of earth’s organisms

  4. Proof of Evolution • DNA Analysis (Gel Electrophoresis)

  5. What did organisms evolve from? Multi-cellular Unicellular

  6. How do organisms acquire new traits so evolution can occur over many years? • Crossing-over during meiosis when gametes are formed • Mutations in gametes (Sperm or egg)

  7. Recombination in Gametes • Crossover (Sorting) during meiosis (Meiosis- special cell division when gametes are formed)

  8. Mutation in Gametes • Base pair sequence change • Change passed on to offspring

  9. Leads to Variety • Sexual Reproduction (Crossover during meiosis) • Mutations

  10. Variation in Dogs

  11. Variation in Ladybugs

  12. Variation in Frogs

  13. Variation in Finches

  14. Passed to Offspring • Mutations passed to offspring when they occur in gametes(sperm or egg)

  15. 1.Which phrase best defines evolution? 1.an adaptation of an organism to its environment 2.a sudden replacement of one community by another 3.a geographic or reproductive isolation of organisms 4.a process of change in organisms over a period of time

  16. 2.Which two factors provide the genetic basis for variation within a species? 1.asexual reproduction and geographic isolation 2.mutations and sexual reproduction 3.competition and protein synthesis 4.constant gene frequency and reproductive isolation

  17. 3.As a result of sexual reproduction, an organism can pass a gene mutation to its offspring if the mutation occurs in 1.a body cell 2.a gamete 3.liver tissue 4.white blood cells

  18. AimHow does evolution occur?

  19. Struggle for Existence • Members of each species compete for food, living space and the necessities of life • A finite supply of resources

  20. Fitness • The member that is better fit will survive. • Fitness-The ability to survive

  21. Adaptation • An inherited characteristic that increases an organism’s chance for survival Quills

  22. Example-Adaptation • Long tongue lizard is better adapted than a lizard with a short tongue.

  23. Survival of the Fittest • Individuals that are better suited to their environment - survive and reproduce more successfully

  24. Natural Selection • Survival of the fittest is also referred to as Natural Selection • Environment changes first, those best adapted survive

  25. Adaptations • Beneficial traits will be passed on to offspring (More frequency) • Unfavorable traits will be less common

  26. Favorable Traits • Those best adapted pass on favorable adaptations to their offspring • Higher frequency of favorable traits are passed along to offspring increasing chances for survival of the species Camouflage

  27. 1.In most populations, the individuals that produce the greatest number of offspring are 1.always the strongest 2.usually the best adapted 3.those that have only recessive traits 4.those that are the most intelligent

  28. 2.According to modern evolutionary theory, genes responsible for new traits that help a species survive in a particular environment will usually 1.not change in frequency 2.decrease gradually in frequency 3.decrease rapidly in frequency 4.increase in frequency

  29. 3.Even though the environment changes, a population that occupies a given geographic area will most likely continue to be found in this area if the 1.variations in the population decrease over time 2.members of the population decrease in number 3.members of the population exceed the carrying capacity 4.population passes on those genes that result in favorable adaptations

  30. Aim What conditions are important to evolution?

  31. Force behind Evolution • The interaction between individual organisms and the environment

  32. Conditions Important to Evolution • Variation (Differences) • Overproduction • Finite supply of resources (limited) • Natural Selection

  33. Variation • New traits that can lead to evolution come from normal variation within species

  34. Overproduction • Population of a species remains stable • Turtle eggs

  35. Struggle for Survival • Finite Resources (not enough) • Competition among individuals of a species mean only the most adapted to the environment will survive

  36. Natural Selection • Evolution is controlled by nature not people • Organism that are best adapted to an environment will survive

  37. Selection by Environment • The proportion of individuals with advantageous traits will increase • This change over time is evolution

  38. AIMWhat are the changes organisms undergo from Genetic Variation?

  39. Sources of Variation • Sexual Reproduction (Crossover during Meiosis) • Mutations

  40. Results of Variation 1.Structural Change 2.Functional Change 3.Behavioral Change

  41. Structural Change • Homologous structures - Have different mature forms but developed from the same ancestors (embryonic tissues)

  42. The bones in the forelimbs of three mammals are shown below. For these mammals, the number, position, and shape of the bones mostlikely indicates that they may have • developed in a common environment • developed from the same earlier species • identical genetic makeup • identical methods of obtaining food

  43. Functional Change • Humans-Electrical Impulses to move muscles • Eels -Electrical impulses to shock and kill its prey

  44. Behavioral Change • Rate of light blinking helps organisms recognize same species for mating

  45. Some behaviors such as mating and caring for young are genetically determined in certain species of birds. The presence of these behaviors is most likely due to the fact that • birds do not have the ability to learn • individual birds need to learn to survive and reproduce • these behaviors helped birds to survive in the past • within their lifetimes, birds developed these behaviors

  46. Evidence of Common Ancestors • If Amino acid sequence in proteins they synthesize are similar • Suggests DNA is also similar (Controls Synthesis)

  47. Things to Remember • Individuals that produce the most offspring are the best adapted to the environment

  48. The kit fox and red fox species are closely related. The kit fox lives in the desert, while the red foxinhabits forests.Ear size and fur color are two differences that can be observed between the species.An illustration of these two species is shown below.  Which statement best explains how the differences between these two species came about? • Different adaptations developed because the kit fox preferred hotter environments than the redfox. • As the foxes adapted to different environments, differences in appearance evolved. • The foxes evolved differently to prevent overpopulation of the forest habitat. • The foxes evolved differently because their ancestors were trying to avoid competition.

  49. Aim What affects the rate of evolution among organism?

  50. Affects Rate of Evolution • Environmental Change - More Environmental change equals more Evolution - Less Environmental change equals less Evolution Horseshoe crab

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