Darwin: Natural Selection, & Evolution Chapter 13

What you need to know! How Lamarck’s and other notable predecessors’ views of the mechanism of evolution differed from Darwin’s. The difference between structures that are homologous and those that are analogous, and how this relates to evolution. The role of adaptations, variation, time, reproductive success, and heritability in evolution.

Preceding Darwin Aristotle 384-322 BC – Scala naturae: oragnization of life based on increasing complexity Linnaeus 1707-1778 – taxonomy: naming and classifying all organisms, binomial nomenclature: genus and species Cuvier 1769-1832 – father of paleontology, study of fossils leads to theory of catastrophism (mass extinction) which explains the boundaries between strata and the location of different species

Preceding Darwin Hutton 1726-1797 & Lyell 1797-1875 – Theory of Gradualism (uniformitarianism): Earth geology changes slowly and continuously The Earth must be VERY old Darwin studied Lyell’s work

Preceding Darwin Lamark 1744-1829 – 1st theory of evolution Use or disuse of body parts leads to their development or deterioration (acquired characteristics) Inheritance of acquired characteristics

Charles Darwin Born in England in the 1800’s Went to college Rich family Went to college Studied the bible Sailed around the world studying life Pictures, fossils, samples Wrote the book: The Origin of Species Father of Evolution by Natural Selection

Darwin’s Journey Darwin was fascinated by life He wanted to learn about all different kinds He sailed around the world in the mid 1800’s aboard the H.M.S. Beagle

Darwin Video: http://www.pbs.org/wgbh/evolution/library/11/ 2/quicktime/e_s_2.html

The Galapagos Islands It was in the Galapagos Islands that Darwin made his most famous observations

The Galapagos Islands Pinta Island Intermediate shell Hood Island Hood Section 15-1 Pinta Tower Pinta Island Intermediate shell Marchena James Fernandina Santa Cruz Isabela Santa Fe Hood Island Saddle-backed shell Floreana Hood Isabela Island Dome-shaped shell

Darwin’s Finches Darwin gathered many finches from all the Galapagos Islands He noticed that each finch from each island was slightly different They have a beak best suited to eat the food available on their island

Darwin’s Finches

Artificial Selection (Selective Breeding) Darwin modeled natural selection after artificial selection: Humans choose which traits they like and use selective breeding to manipulate the traits

Evolution by Natural Selection Individual organisms differ, and some of this variation is heritable. Organisms produce more offspring than can survive. Because more organisms are produced than can survive, organisms compete for limited resources.

Evolution by Natural Selection Individuals best adapted to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring. Species alive today are descended with modification from species that lived in the distant past. If you go back far enough all life on this planet is linked in one great tree of life.