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Patterns In Evolution

Patterns In Evolution. Two Major Patterns Observed. MACROevolution And micro evolution. Macroevolution. Macroevolution: evolution of groups larger than an individual species. Takes a long period of time. Macro= looking at bigger sections of evolution.

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Patterns In Evolution

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  1. Patterns In Evolution

  2. Two Major Patterns Observed MACROevolution And microevolution

  3. Macroevolution • Macroevolution: evolution of groups larger than an individual species. Takes a long period of time

  4. Macro= looking at bigger sections of evolution

  5. The 6 Patterns that influence how macroevolution occurs are… 1-Mass Extinctions - 2-Adaptive Radiation 3-Convergent or Divergent Evolution 4-Co-evolution 5-Punctuated Equilibrium 6-Gradualism

  6. Mass Extinction • Loss of complete huge number of species and ecological systems • Causes could be: • large asteroid during the Cretaceous period l throwing huge amonts of dust and vapor altering global climate affects organisms…like dinosaurs • Volcanic eruptions, continental shifts, changing sea levels, other major environmental changes

  7. Adaptive Radiation • A single species or a small group of species evolved into several different forms and live in different ways • Darwin’s Finches

  8. Convergent Evolution • Unrelated organisms come to resemble each other • This effect is due to different organisms undergoing adaptive radiation in different places BUT in ecologically similar environments • Face similar environmental demands • Examples: streamlined bodies and flippers of water organism ( shark, dolphin, seals, penguins)

  9. Convergent Evolution

  10. Divergent Evolution • Because of different environments organisms begin to look more and more different over generations • Ex) Dog and Wolf

  11. Coevolution • Two species evolve in response to each other due to ecological interactions • Flowers and insects(Madagascar orchid and hawk moth) • Plants and plant eating insects: plants have developed poisons to prevents plant eating insects from feeding on them. Natural selection in insect eating plant favored variants that could alter, inactivate, or eliminate the poisons both organisms change in response to each other

  12. Coevolution

  13. Macroevolution is also influenced by… RATE • Rate= how quickly the evolution occurs Quick= Punctuated Equilibrium Gradual= Gradualism

  14. Punctuated Equilibrium • Pattern of long, stable periods interrupted by brief periods of rapid changes. Punctuated on the right

  15. When does this type of evolution occur? • Small populations become isolated from the main part of the population .Population changes quicker because genetic changes can spread more quickly among fewer organism • Small group of organisms migrate to a new environment GALAPAGOS FINCHES

  16. Gradualism slow change in a population over a long period of time

  17. Microevolution • Quick change in gene frequency within a population. • Quicker then macroevolution. • observed over short periods of time Examples: Antibiotic resistance, Pesticide resistance

  18. Antibiotic resistance Bacteria can evolve quicker when they are resistant to the antibiotic. This is because of genetic shuffling due to their quick reproduction rateswhich means more chances for mutation (changes) less likely to be killed by antibiotics if they have changed their genes SO SMART!! http://www.pbs.org/wgbh/evolution/library/11/2/quicktime/e_s_6.html

  19. Microevolution example • Imagine that you go to the mountaintop this year, sample these beetles, and determine that 80% of the genes in the population are for green coloration and 20% of them are for brown coloration. You go back the next year, repeat the procedure, and find a new ratio: 60% green genes to 40% brown genes. • You have detected a micro evolutionary pattern: a change in gene frequency. A change in gene frequency over time means that the population has evolved.

  20. What caused the microevolution? • Mutations in genes • Migration of organism • Genetic Drift of alleles • Natural Selection of the environment for a given trait

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