1. EVOLUTION

2. Evolution – The process by which modern organisms have descended from ancient organisms.

3. Evolution – The process by which modern organisms have descended from ancient organisms.

4. Adaptation – A trait that helps an organism be better suited to its environment.
ex) a ducks webbed feet

5. Adaptation – A trait that helps an organism be better suited to its environment.
ex) an arctic fox’s heavy fur coat

6. Fitness – The physical traits and behaviours that better enable organisms to survive and reproduce in their own environment.
What makes these polar bears fit to live in the arctic?

7. What makes this fenec fox fit to survive in the extremes of the Sahara Desert?

8. EXPLANATIONS FOR EVOLUTION
Around 1800, scientists began to realize that living things changed over time.

9. Jean Baptiste de Lamarck
Lamarck is considered to be the first person to develop a theory of how evolution occurred.
He is credited with encouraging future scientists to examine how evolution occurred.

10. Lamarck’s Big Ideas Desire to change Law of use and disuse
Inheritance of acquired characteristics

11. Lamarck also believed body parts could change shape or size depending on needs.
Lamarck explained the long neck of a giraffe by saying if it stretched its neck for leaves a “nervous fluid” would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations. Meanwhile organs that organisms stopped using would shrink.

12. Lamarck believed in the inheritance of acquired characteristics.
Consider the ears and tails of Doberman Pinschers.

13. Charles Darwin
English naturalist
travelled around the world on the H.M.S. Beagle observing plant and animal life
the trip took over 5 years

14. Further Influences on Darwin:
Charles Lyell (a rock star - geologist)
he argued the Earth was very old while most believed earth to be a few thousand years old
this meant common descent could have had enough time to occur

15. Further Influences on Darwin:
Farmers
Darwin knew farmers altered their stocks with breeding programs (artificial selection)
with a.s. humans ensure only animals with desirable traits are allowed to breed
Darwin felt nature must have a similar process only allowing the best suited to the environment to survive

16. Further Influences on Darwin:
Thomas Malthus
he realized babies were being born faster than people were dying
he felt only famine, disease and war would prevent endless human population growth
Darwin extended this to plants & animals as he realized many individuals of each species die and few raise offspring. The question was what determined who survived and reproduced?

17. The Beagle’s Journey

18. Darwin’s time on the Galapagos Islands had a big impact on him developing his theory of evolution.

19. marine iguana

20. flightless cormorant
Galapagos penguin

21. Sally Lightfoot crab

22. frigate bird

23. Galapagos Tortoises – These were important to Darwin developing his Theory of Evolution.

24. The islands were once home to 15 different sub-species
The islands were once home to 15 different sub-species. 11 of these remain today. One sub-species only has one individual.
Lonesome George – the last of his kind

25. Five sub-species are found on Isabela and one each on Santiago, Pinzon, Santa Cruz, Española and San Cristobal. Lonesome George is from Pinta but lives on San Cristobal today in a breeding facility.

26. The main differences between sub-species is the length of their limbs and necks and the shape of their shells.

27. Galapagos Finches
The 13 species of Galapagos Finches were also important to Darwin developing his Theory of Evolution.

28. Darwin decided that species change over time
in 1859, he published his famous book that describes his theory of evolution

29. a key part of the theory was the idea of Common Descent
a key part of the theory was the idea of Common Descent. It argued all species have evolved from one common ancestor.
an evolutionary tree, from one of Darwin’s notebooks

30. Darwin’s Theory of Natural Selection states:
more organisms are born than survive
- the environment can’t support them all

31. Darwin’s Theory of Natural Selection states:
organisms vary within a species
- no two individuals are exactly alike

32. Darwin’s Theory of Natural Selection states:
survival of the fittest
organisms with favourable variations survive and reproduce
the individuals with characteristics not well suited to their environment either die or leave fewer offspring
in this way, favourable variations are passed from generation to generation

33. Darwin’s Theory of Natural Selection states:
a population that is adapted to its environment will result

34. Natural Selection

35. In 1858 Alfred Wallace wrote to Charles Darwin about his ideas of evolution.
His work also describes the theory of natural selection.
Wallace and Darwin co-published a paper on evolutionary theory and are considered the co-discoverers of the Theory of Evolution.
Each man gave the other as much credit as possible.