1. The Evolution of Evolution Historic ideas about organisms and how they change over time

2. Aristotle (384 - 322 B.C.) ● “Ladder of life” ● Nature is ordered from lower to higher ● No vacant rungs ● No movement up or down the ladder ● Included living and non- living things

3. Jean-Baptiste Lamarck (1744-1829) ● First scientist to propose a mechanism for how organisms change (1809) ● His idea: “Inheritance of Acquired Traits” ● Greater use of a body part would change it, and the change would pass on to the organism’s offspring.

4. Use and Disuse  Organisms could alter the size or shape of organs  USE: giraffe stretching its neck to reach taller trees  DISUSE: if a bird did not use its wings, then they would decrease and disappear

6. Lamarck’s Assumptions 1.Organisms have a desire to change. They have an inborn urge to better themselves for their environment. Ex: Birds tried to fly and eventually grew wings because of their efforts.

7. Lamarck’s Assumptions 2. Organisms can change shape by using or not using their bodies. Ex: The wings of a bird that does not fly would get smaller from generation to generation and the wings would eventually disappear.

8. Lamarck’s Assumptions 3. Organisms can pass on acquired traits to their offspring. Ex: If an animal developed muscles from lifting weights during its lifetime, it could pass those muscles on to its offspring.

9. Charles Darwin (1809-1882) ● English naturalist ● Traveled around the world on the Beagle (1831); famously stopped in the Galapagos Islands ● Observed many species and fossils ● Particularly studied finches, tortoises, blue-footed boobies

11. Galapagos Islands  Small islands of the western coast of S. America  Close together but different climates  Smallest/lowest were hot, dry, barren  Higher ones had more rain and greater diversity of life

13. The Galapagos Islands (Ecuador)

14. Patterns of Diversity  Darwin was puzzled by species and where they lived  No kangaroos in England  No rabbits in Australia  Collected fossils  Why did species disappear?  How are they related to living species?

15. Wildlife  Tortoises- the shape of the shell could be used to identify which island a particular tortoise inhabited.  Finches – birds on different island with different beaks

17. “Darwin’s finches” ● Darwin noticed that finches were different on each Galapagos Island. ● He concluded that the different finches had descended from a common ancestor and had changed to be able to do and eat different things.

19. “Descent with Modification” After his studies, Darwin came up with 4 main ideas… 1.Individuals differ, and some of this variation can be inherited. 2.Organisms produce more offspring than can survive; thus they have to compete for resources, and only the most fit will survive and reproduce. 3.The most fit organisms pass on their heritable traits to their offspring. 4.Species alive today are descended with modification ( change ) from their ancestors.

20.  Natural Variation : differences among individuals of a species  Artificial selection : humans select those variations that they find useful (dogs)  Descent with modification: change in organisms over time (many generations)  Natural Selection: pressure the environment puts on the specific traits that affects their ability to survive  Evolution: change over time  Common Descent: All living organisms are related to one another  Differential Reproduction: individuals that have certain traits are more likely to survive and pass on those traits (they become more frequent) Therefore we now call Darwin’s idea ‘biological evolution” DEFINITIONS

21. Lamarck’s explanation for the giraffe’s long neck:

22. Darwin’s explanation for the giraffe’s long neck:

23. Thomas Malthus (1766-1834) British clergyman and scholar His prediction:  the human population would grow faster than the space and food supplies needed to sustain it.  The only checks on the human population would be war, famine, and disease.

24. Influence of Malthus on Darwin Malthus’ theory of population growth was observed by Darwin in other animal populations as well. In nature, Darwin saw many organisms that produced many offspring. Most died. Darwin wondered, what determines which individuals survive and reproduce ?

25. James Hutton and Charles Lyell British Geologists  Hutton is considered the “father of modern geology”  Based on layers found in rock structures, Lyell proposed that Earth is millions of years old  Lyell proposed that geological features could be built up or torn down over long periods of time  stressed that scientists must explain past events in terms of observable processes (volcanoes, erosion) Grand Canyon, Arizona

26. Influence of Geology on Darwin  After reading Lyell’s book, Darwin was convinced that Earth was old.  Darwin reasoned that if geological phenomena could change the earth, then life on Earth could change as well.