Natural Selection/ Evolution Study Guide

Science Natural Selection/Evolution Study Guide

Important People: - Charles Darwin developed the theory of evolution by natural selection after collecting and studying many organisms on the voyage of the H.M.S. Beagle. - Jean Baptiste Larmarck (1700s): he was a soldier and a biologist and an early proponent of the idea of evolution and natural laws. - George Cuvier (1800s): Was in instrumental in establishing the field of comparative anatomy through his work in comparing living animals with fossils. He established extinction as a fact. - Charles Lyell’s (1800s): his interests ranged from volcanoes to stratiography or basically Prehistoric Archaeology. He argues that earth was shaped by slow moving forces still in operation today. - Alfred Wallace: best known for independently proposing a theory of evolution due to natural selection. (This prompted Charles Darwin to publish his theory)

Important Vocabulary: - Evolution: the development of new types of organisms from preexisting types of organisms over time. - The theory of Natural Selection: the process in which individuals that are better adapted to their environment survive and reproduce more successfully than less adapted individuals. Their environment selects the traits. - Homologous Structures: anatomical structures that occur in different species and that originated by heredity from a structure in most recent common ancestor of species. - Analogous Structures: anatomical structures that have closely related functions but do not derive from the same ancestral structures. (ex. Wings of birds vs. wings of butterflies or insects) - Vestigial Structures: Anatomical structures that seem to fit no function but that resemble structures with functional roles in related organisms. (eyes of moles, human coccyx, human appendix) - Phylogeny: the relationship by ancestry among groups of organisms using a tree or cladogram.

Identify 4 points of reasoning in Darwin’s Theory of Evolution by Natural Selection.

1. There is variation within individuals of a population 2. Some variations are inherited 3. Some individuals survive and reproduce better than other individuals 4. Differential survival and reproduction (Darwinian fitness) is influenced by the heritable traits of individuals

Evidence of Darwin’s Theory: - Fossil Record: the remains of an organism that died a long tome ago; by looking at fossil record scientists are able to determining how species evolved and from what species. - Ancestor: the study of a body structure of an organism. As generations pass different populations of descendants adapted to their environments thus limbs and bones change. (ex. Horse’s feet and teeth) - Embryology: the study of how organisms develop. - Biological Molecules: DNA, RNA, Proteins. These molecules can be compared between species to look for similarities and differences. - Adaptations: camouflage (pepper moth), mimicry (yellow jacket wasp), Gene mutations (antibiotic resistant bacteria, favorable mutations change an organism’s physiology). - KNOW THE FOLLOWING ARE EXAMPLES: Sickle Cell anemia, industrial melanism, Galapagos finches, Galapagos Tortoises.

What is the difference between Allopatric Speciation and Sympatric Speciation?

- Well… Allopatric speciation means that speciation occurred in different regions. Sympatric speciation means that one population of one species became two species while in the same geographic region with no physical separation.

Graphs of Natural Selection:

Disruptive Selection: both extremes of a phenotype are favored over the averages.
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Directional Selection: The overall makeup of a population shifts to one extreme away from the average.
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Stabilizing Selection: the POPULATION average is favored, and acts AGAINST the extremes in a population.
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How does Gradualism differ from Punctuated Equilibrium?

Punctuated equilibrium is a theory of evolutionary biology which states that most sexually reproducing populations experience little change for most of their geological history. A genetic equilibrium occurs when an allele within a gene pool is not changing in frequency (i.e. evolving).