In your own words, write out a definition of evolution. In science, evolution refers not to change in individuals, but in a species over many generations. Evolution- comes from the word evolve

Read about the star-nosed mole in your book on page 297. Two parts of the evolutionary story: descent and modification, or “descent with modification”. Evolution focuses on changes that occur across generations, therefor, the relationship can be described in terms of descendants (an individual who can be traced back to a particular family or group) and ancestors (an individual or group from wh0m one is descended). What sorts of modification are obvious in the star-nosed mole? (ray-like feelers, poor eyesight, prominent claws) How do such traits arise to begin with? (mutation) What is the role of descent in evolution? (mutations can be passed on from one generation to the next.) How do mutations arise? What other factors could be at work in generations of star-nosed moles that have caused the moles to have the features that they do? (environment)

KEY CONCEPT There were theories of biological and geologic change before Darwin. Most people believed that the world was only 6000 years old and that the earth and the organisms that inhabit it did not change over that time. The also believed that species could not become extinct.

Early scientists proposed ideas about evolution. Evolution is the biological change process by which descendants come to differ from their ancestors. Darwin= credit, but the idea was tossed about for about 100 years before him.

There were many important naturalists in the 1700s. Carolus Linnaeus: created a classification system from kingdom to species Came to believe that animals could change over time. Some could have arisen through hybridization. A species is a group of organisms that can reproduce and have fertile offspring. Linnaeus: Sweedish botanist He grouped animals by similarities. Interestingly, his system also reflects evolutionary relationships. The system is still in use today.

There were many important naturalists in the 1700s. Georges Louis Leclerc de Buffon based on evidence of past life on earth (fossils), he believed that species shared ancestors rather than arising separately believed the world was much more than 6000 years old Age of earth: similar to Charles Lyell, a geologist who influenced Darwin in later years

There were many important naturalists in the 1700s. Erasmus Darwin (Charles Darwin’s grandfather) Proposed that all living things were descendants of a common ancestor more-complex forms developed from less-complex forms Respected english doctor and poet

There were many important naturalists in the 1700s. Jean-Baptiste Lamarck Believed that all organisms evolved toward perfection and complexity environmental change leads to use or disuse of a structure (organ, limb, etc.). We know this is not true. Changes in the environment lead to changes in behavior, leading to greater use or disuse or organs or limbs. The structure would become larger or smaller over time. That changed structure would be passed to its offspring. He did not propose how these traits were passed on, but his ides influenced Darwin none the less.

Theories of geologic change set the stage for Darwin’s theory. There were three theories of geologic change supporting the idea that the earth was mush older. Catastrophism Gradualism Uniformitarianism

Theories of geologic change set the stage for Darwin’s theory. Georges Cuvier- geologist Did not believe that species could change, but believed that they could become extinct. Observed stratum (layers of rock) each held specific types of fossils (traces of organisms that existed in the past (ex. bones, eggs, carbon prints, tracks, nests, poop)) Catastrophism- natural disasters happened in the past, could shaped the land and make organisms go extinct. He said that new fossils in the area come from other species that moved in after the disaster

Theories of geologic change set the stage for Darwin’s theory. James Hutton- geologist Gradualism- changes in landforms happened slowly over a long period of time Charles Lyell- geoloist Uniformitarianism- states that the geologic processes that shaped earth are uniform through time He said that new fossils in the area come from other species that moved in after the disaster

Uniformitarianism is the prevailing theory of geologic change.