Evolution and Charles Darwin A.

Chapter 13: The Theory of Evolution

II. Charles Darwin
A. In 1831, as a naturalist, went on a voyage on the Beagle in the southern hemisphere, including the east coast of Africa.
B. Before Darwin, most people believed in divine creation.
C. As a naturalist, he saw evidence that species may have evolved from a common ancestor, like the finches.
D. Darwin also saw evidence that the earth is very old.
E. He said that natural selection is the mechanism of how organisms adapted to their environment.
F. Waited 20 year to publish his book On the Origin of Species.
G. Very controversial, especially the part where man evolved from apes.
H. Not the first with these ideas, but the first to publish.
III. Natural Selection
A. The more fit individuals or species will survive, adapt or change, and reproduce over time.
B. Reasons for change
1. Mutations – Change because of genetic “errors”
2. Gene flow – Change because organisms move or seeds carried somewhere else and mate with different group.
3. Nonrandom mating – Change because of selecting mate, like mating dance.
4. Genetic drift – Only certain members reproduce by chance, like a natural disaster.
IV. Evidence of Evolution Today?
A. Fossils
1. Older organisms deposited deeper in strata
2. See evidence of changes over millions of years.
B. Biogeography
1. Distribution of plants and animals that had a common ancestor to different areas.
2. When in different areas, develop different characteristics, like snakes in gene flow.
C. Anatomy
1. Vestigial structures – Structures which are fully developed in one organism, but not used and nonfunctional in another. Ostrich wings, human tailbones.
2. Homologous structures – Same bones in different organisms.
Embryos are very much alike.
D. Biochemical
1. All organisms have similar cell components such as membrane, mitochondria.
2. All organisms have amino acids – 1 different in primates and humans.
3. Nucleic acids – DNA and RNA

V. Specification – Making a new species A. Species definition 1. Members of species interbreed 2. Have shared gene pool 3. Reproductively isolated from another species 4. Have fertile offspring