Darwin’s Theory of Evolution The Puzzle of Life’s Diversity Chapter 15-1 Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006

What scientific explanation can account for the diversity of life? ANSWER: A collection of Scientific Facts, observations and hypotheses EVOLUTIONARY THEORY-

WRITE A DEFINITION: change over time; the process by which modern organisms have descended from ancient organisms a well-supported testable concept that is supported by evidence EVOLUTION : THEORY :

The person who contributed the most to our understanding of evolution was Charles Darwin In 1831, he joined the crew of the Beagle as a naturalist for a 5 year voyage around the world. Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006

DARWIN WONDERED? Why do Argentina and Australia have different Animals even though they have similar grassland? Why are there no rabbits in Australia and no kangaroos in England? Why have so many species disappeared? How are these extinct species related to living species?

Fossil record showed 2 types of organisms –Ones that were similar to animals and plants alive at the time –Ones that were different to animals an plants alive at the time Why had these species disappeared?

Charles Darwin spent one month observing life on the Galapagos Islands. There, he encountered some unique animals, such as finches and tortoises. Darwin's greatest influence

The Galάpagos Islands are close together but have very different climates. hot and dry, with little vegetation more rainfall and were rich in vegetation Each island had its own unique Assortment of plant and animal species. Biology by Miller and Levine; Prentice Hall Publishing©2006

Go to Section: Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandina Isabela Tower Giant Tortoises of the Galápagos Islands Section 15-1 On the desert-like Hood Island, tortoises had long necks… …while on the lush rainforest of Isabela Island, tortoises had short necks… and on Pinta Island, tortoise necks were somewhere in between

After his voyage, Darwin spent a great deal of time thinking about his findings. Biology by Miller and Levine; Prentice Hall Publishing©2006

Darwin’s Theory of Evolution Ideas that Shaped Darwin’s Thinking Chapter 15-2 Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006

Ideas that shaped Darwin’s thinking: James Hutton (1795)- the EARTH was shaped by geological forces occurring over very long periods of time, and the Earth is millions of years old.

Ideas that shaped Darwin’s thinking: Charles Lyell (1830)- the geological processes still occurring now have shaped Earth’s features over long periods of time

Ideas that shaped Darwin’s thinking: Theory of Pangaea

Ideas that shaped Darwin’s thinking: Continental drift convergent divergent Transform

Ideas that shaped Darwin’s thinking: Thomas Malthus (1798)- If the human population continued to grow unchecked, there would be insufficient living space and food.

Ideas that shaped Darwin’s thinking: Jean-Baptiste Lamarck (1830)- one of first scientists to recognize living things changed over time and that all species were descended from other species. Lamarck's Hypothesis: 1.Tendency towards perfection 2.Use and disuse 3.Inheritance of acquired traits

What’s wrong with Lamarck’s hypothesis? Lamarck didn’t know about genes and how traits are inherited. If you lifted weights your whole young adult life, and then you had children, would your kids be more muscular? NO! acquired traits can not be passed on to their offspring.

The male fiddler crab uses its front claw to attract mates and fight off predators. Through repeated use, the front claw becomes larger. The fiddler passes on this acquired characteristic to its offspring Individuals DO NOT evolve!!!!

Acquired traits cannot be inherited

What’s right with Lamarck’s hypothesis? Lamarck was first to develop a scientific hypothesis about evolution and recognize that organisms are Adapted to their environment

competition Inherited adaption's that accumulate in a population over many generations= Evolution Living things must compete for food, shelter, space and mates What does drive evolution?