1. Chapter 16 Darwin’s Theory of Evolution

2. What is evolution??

3. It simply means…… A change in an organisms genes, over periods of time (usually long ones!!) However this is changing with MRSA and viruses HIV and Influenza each year. A change in an organisms genes, over periods of time (usually long ones!!) However this is changing with MRSA and viruses HIV and Influenza each year. Why is it a “theory”??? Why is it a “theory”??? –A theory is a well-supported explanation of things that have happened in the natural world.

4. How did this theory start??? By Charles Darwin (2/12/1809) – same day as Abe L. By Charles Darwin (2/12/1809) – same day as Abe L. He sailed on the HMS Beagle, (5 years) and brought back new animals, plants, bones, fossils etc.. He sailed on the HMS Beagle, (5 years) and brought back new animals, plants, bones, fossils etc..

5. His observations…Diversity - Why do similar ecosystems on different continents contain different animals??? Why do similar ecosystems on different continents contain different animals??? Ex: no rabbits in Australia, no kangaroos in England? Ex: no rabbits in Australia, no kangaroos in England?

6. Fossils - Some look similar to modern species Some look similar to modern species Some look so different they must no longer exist today Some look so different they must no longer exist today

7. The Galapagos Islands- 1000 km. off the coast of Ecuador 1000 km. off the coast of Ecuador Islands are close, but have different climates. Therefore they have similar species but with unique differences. Islands are close, but have different climates. Therefore they have similar species but with unique differences.

8. Look at the beaks: what are they adapted for? Did they all start out the same and then change?

9. Tortoises - The tortoises on each island have different shells. The tortoises on each island have different shells. On Hood Island, vegetation is sparse and higher up. The tortoise shell is notched, not so on islands with low lying vegetation. On Hood Island, vegetation is sparse and higher up. The tortoise shell is notched, not so on islands with low lying vegetation.

10. Galapagos cont’: Marine iguanas are found here but no where else on Earth – why? Marine iguanas are found here but no where else on Earth – why?

11. 16 – 2 Darwin’s ideas Earth is not only a few thousand years old Earth is not only a few thousand years old Hutton and Lyell proved this by geological layers and processes. (Continental drift) Hutton and Lyell proved this by geological layers and processes. (Continental drift)

12. Population Growth: Malthus – if the population grows unchecked, there won’t be enough space and food for everyone. Life must be a struggle to survive -Are we seeing this today? Malthus – if the population grows unchecked, there won’t be enough space and food for everyone. Life must be a struggle to survive -Are we seeing this today? In animals and plants – only a few young survive…. WHY?? Is this true of humans ? In animals and plants – only a few young survive…. WHY?? Is this true of humans ?

13. LaMarck – Use and disuse If an organism uses something a lot – it will pass that trait on to its’ offspring: If an organism uses something a lot – it will pass that trait on to its’ offspring:

14. Origin of Species - 1859 Book published by Darwin. Caused an uproar because people thought it went against the church, in that species were created from previous species – not specially created from God. Book published by Darwin. Caused an uproar because people thought it went against the church, in that species were created from previous species – not specially created from God.

15. Artificial Selection: Artificial Selection: Nature provides variation, while humans select the traits they want. Nature provides variation, while humans select the traits they want. Pig farmers will breed the largest pigs, cows that milk best etc…. Look at all the dog species! Pig farmers will breed the largest pigs, cows that milk best etc…. Look at all the dog species!

16. Survival of the Fittest: The best adapted live and reproduce. Organisms inherit characteristics that increase their chances of survival. Ex: a lizard that sheds its tail will survive to reproduce instead of dying out. Organisms inherit characteristics that increase their chances of survival. Ex: a lizard that sheds its tail will survive to reproduce instead of dying out.

17. Descent with modification: Species today look different than their ancestors – because they have descended and changed over time. Some still look remarkably the same though….crocodiles? Species today look different than their ancestors – because they have descended and changed over time. Some still look remarkably the same though….crocodiles?

18. Evidence of Evolution: Fossil record, changes in Earth have been seen (continental drift, volcanoes, earthquakes, uplifting of mountains) Fossil record, changes in Earth have been seen (continental drift, volcanoes, earthquakes, uplifting of mountains) Geographical distribution of living species Geographical distribution of living species Homologous structures Homologous structures Similarities in early development Similarities in early development

19. Fossil Record: Show ancestors and their gradual changes into current species. Show ancestors and their gradual changes into current species. Fossils show differences Fossils show differences in horse size, feet, in horse size, feet, skulls etc.. skulls etc.. Several species are well mapped! (dinosaurs, elephants, mapped! (dinosaurs, elephants, Horses etc..)

20. Geographical distribution: Animals share a common ancestor, but were isolated and evolved different traits specific to that environment (blubber, fins, beaks, fur) Animals share a common ancestor, but were isolated and evolved different traits specific to that environment (blubber, fins, beaks, fur) Isolated islands typically have their own species (Australia). No snakes on Guam etc.. Isolated islands typically have their own species (Australia). No snakes on Guam etc..

21. Early Development: Embryology Look at how similarly organisms look as they develop from a fertilized egg. Human embryos have gills slits and tails… Look at how similarly organisms look as they develop from a fertilized egg. Human embryos have gills slits and tails…

22. Similar Body Structures: Homologous structures Resemblance in all front limbs of very different animals: Resemblance in all front limbs of very different animals:

23. Vestigial Organs: Serve no purpose now, but at one time probably did. Serve no purpose now, but at one time probably did.

24. Similar Chemical Compounds: All living things use ATP for energy. All living things use ATP for energy. All living things reproduce by DNA (same nucleotide bases) All living things reproduce by DNA (same nucleotide bases)

25. Humans and apes?? DNA in apes and man is 97% the same. Humans have 46 chromosomes, apes 48. They look the same except that #2 is fused in humans and separate in apes: DNA in apes and man is 97% the same. Humans have 46 chromosomes, apes 48. They look the same except that #2 is fused in humans and separate in apes:

26. Fossil Record Problems - Incomplete – getting stronger everyday. Incomplete – getting stronger everyday. Finding “missing links”. Many living things don’t Many living things don’t turn in to fossils. Quality of fossils vary. Quality of fossils vary. Dating can be difficult. Dating can be difficult. http://www.youtube.com/watch?v=yDdaSt k5SEM