Natural SelectionThe Mechanism to Explain

How Evolution Works

Who was Charles Darwin? (1809 – 1882)

• 1. British Naturalist – from a wealthy family, well educated, trained in theology

• 2. H.M.S. Beagle: at age 22 he sailed the world for 5 years as the ships naturalist (instead of getting a real job like his family would have preferred.)

• 3. Credited with the “Principles of Natural Selection as the mechanism for evolution”

Who was Jean-Baptiste de Lamarck? (1744 – 1829)

• French naturalist who came up with the idea of “Acquired Characteristics” to explain how evolution works.

How do the Ideas of Lamarck and Darwin compare?

• both were trained naturalists

• both believed in evolution: that species change over time

Lamarck• Organisms acquire traits they need to

survive and then pass those traits to their offspring.

• Organisms naturally vary or differ and the strongest survive, passing on those traits to their offspring.

Darwin

Darwin’s Travels:• At age 22 he set sail on the HMS Beagle for 5

years.• Explored the South American coast. • On his travels he saw an amazing diversity of life

and began to formulate his theory of natural selection.

• His time in the Galapagos Islands are most famed for showing diversity.

• Fossils he found in South America were also very important to his theory.

Farmers

• Breed animals and plants to get certain traits in their livestock and crops, called artificial selection.

Robert Malthus (1766 – 1834)

• An economist.• Wrote about industrialized society and it’s

plights. Many, many people were moving to cities and there were many problems as a result.

• “There is an overproduction of offspring” (used to be a good thing on the farm)

• “…not enough resources to go around” (not growing their own food, cutting own firewood, etc)

James Hutton (1726 – 1797) & Sir Charles Lyell (1797 – 1875)

• Geologists.

• Examined rock layers in England and across the Channel in France and then figured out that the world was WAY older than the church taught.

• Fossils of extinct species from deep buried layers supported this.

• Faunal Succession

Alfred Wallace (1823 – 1913)

• Hard working field naturalist who came up with the Principles of Natural Selection on his own while doing fieldwork in Malaysia and Indonesia.

• Wrote to Darwin, someone he looked up to, and told him his theory.

• Darwin sat on Wallace’s work while finishing up his own theory and presented it as all his own.

• Wallace was too busy working out in the jungles half way around the world to defend himself.