Darwinism The Origin of the Species by Natural Selection

Plato Believed there were two worlds A real world that is ideal and eternal An illusory world of imperfection perceived by senses

Aristotle Believed that all living forms could be arranged on a scale of increasing complexity. This was known as scala naturae.

Charles Darwin Son of a prominent physician in England At age 16 his father sent him to the University of Edinburgh to study medicine Enrolled at Christ College at Cambridge to become a clergyman In December of 1831 at the age of 22 he sailed with the crew of the HMS Beagle 1844 – Wrote a long essay on the origin of species by natural selection 1859 – Published The Origin of the Species by Natural Selection

Others Influencing Darwin LinnaeusGeorge Cuvier James Hutton Lyell Jean Bapiste Lamark Wallace

Wrote a paper almost identical Darwin’s unpublished essay and asked for Darwin’s opinion.

Lamark Published his theory of evolution in 1809 ( the year that Darwin was born.) He is most noted for his explanation of how specific adaptations evolved. His emphasis was on adaptation to the environment. Flaw – “acquired characteristics can be inherited”

Lyell Theory of Uniformitarianism Geological process have not changed through out Earth’s history. Encouraged Darwin to publish his essay Origin of the Species before someone else did.

Hutton Gradualism – profound changes in the cumulative product of slow but continuous processes.

Cuvier Largely responsible for the development of paleontology (study of fossils) He advocated catastrophism.

Linnaeus Founder taxonomy Binomial Nomenclature system The scientific name is composed of two names: the genus and species The genus name is capitalized and the species name is lower case. The scientific name is in italics or underlined. Example: Homo sapiens Homo sapiens

Summary of Darwin’s Ideas Natural Selection is the differential success in reproduction, and its product is adaptation of organisms to their environment Natural selection occurs from the interaction between environment and the inherent variability in a population

Variations in a population arise by chance but natural selection is not a chance phenomenon, since environmental factors set definite criteria for reproductive success. Variation and overproduction make natural selection possible

Examples of Natural Selection in Action Average beak depth varies with rainfall Butterfly population adapted to a vegetation change in a ten year period Antibiotic resistant bacteria

Darwin made two claims Modern species evolved from ancestral forms The mechanism for evolution is natural selection

The Evidences for Evolution Artificial Selection Fossil EvidenceComparative Anatomy EmbryologyComparative BiochemistryBiogeography

Figure 22.2 Fossils of trilobites, animals that lived in the seas hundreds of millions of years ago