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Understanding Natural Selection: How Evolution Shapes Species and Traits

Natural selection is the process through which advantageous traits become common in organisms over generations. By producing numerous offspring, variations arise through sexual reproduction and mutations. Those with beneficial traits, such as longer necks in giraffes for better feeding, have greater survival rates and pass those traits to future generations. This can lead to the emergence of new species. Adaptations, whether physical or behavioral, enhance organisms' survival, highlighting the critical role of geographic isolation and differing rates of evolution in shaping the natural world.

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Understanding Natural Selection: How Evolution Shapes Species and Traits

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  1. How Natural Selection Happens

  2. How Natural Selection Works • How does the “fittest” organism happen?

  3. How do we get organisms with the best traits? 1. Lots of offspring

  4. Differences or variations occur in those offspring (due to sexual reproduction or mutations)

  5. Some variations are helpful, this results in a better chance of survival, reproduction, and passing on of those good variations.

  6. Over time, individuals with new variations may become a new species. This is evolution.

  7. Giraffes with long necks exist because… • Mom and Dad giraffe had lots of offspring • Those offspring were each different. • Some had helpful variations (longer necks) which meant better survival (more food) and more likely to reproduce. • Long neck genes get passed on to future offspring, eventually a new species of giraffe occurs.

  8. Mom and Dad bug had lots of offspring • Those offspring were each different. • Some had helpful variations (grey) which meant better survival (not eaten) and more likely to reproduce. • Grey genes get passed on to future offspring, eventually a new species of bug occurs.

  9. http://www.nysci.org/explore/ontour/charlieandkiwi/Charlies-and-Kiwis-Evolutionary-Adventure-Videohttp://www.nysci.org/explore/ontour/charlieandkiwi/Charlies-and-Kiwis-Evolutionary-Adventure-Video

  10. Adaptations are variations that make an organism better suited for its environment. • Adaptations can be physical (on their body) or behavioral.

  11. Adaptations can help an organism….

  12. Attract a mate http://www.youtube.com/embed/REP4S0uqEOc

  13. Warn predators

  14. Hide from predators (camouflage)

  15. http://www.youtube.com/watch?v=k8RlGbpuhgc

  16. Imitate a more dangerous animal (mimicry)

  17. mimicry

  18. Geographic Isolation can allow some variations to appear in a species that might have been otherwise stayed hidden

  19. Geographic Isolation

  20. Geographically Isolated Animal Examples Flightless birds and mouse lemurs

  21. Speed of Evolution

  22. Gradualism- a continuous series of mutations and variations over time will result in a new species.

  23. Punctuated Equilibrium- rapid evolution that occurs when the mutation of a few genes results in the appearance of a new species over a relatively short time. + The 0.1% of bacteria that survives, reproduces and now is resistant to the spray http://www.youtube.com/watch?v=BwuL4J_jEyc&feature=related

  24. How many germs will survive? 20,000 single celled organisms, which are genetically different from the dead, will still survive and continue to reproduce.

  25. So what? Why does evolution matter? http://www.youtube.com/watch?v=6jBD8xfbf4Y

  26. http://www.nytimes.com/2013/04/17/business/report-on-us-meat-sounds-alarm-on-superbugs.html?_r=0http://www.nytimes.com/2013/04/17/business/report-on-us-meat-sounds-alarm-on-superbugs.html?_r=0 April 16, 2013 Report on U.S. Meat Sounds Alarm on Resistant Bacteria http://www.nytimes.com/2013/04/12/world/asia/report-published-on-3-who-died-from-h7n9-bird-flu.html?_r=0

  27. The End of Evolution….or is it? http://www.youtube.com/watch?v=zGqae7vuUWo&feature=PlayList&p=60D07D9950E069A4&playnext_from=PL&playnext=1&index=16

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