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Chap 22


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Modern Age of Biology began:
on November 24, 1859, the day Charles Darwin published On the Origin of Species by Means of Natural Selection
natural selection
is that a population can change over generations if individuals that possess certain heritable traits leave more offspring than other individuals. (Guiding forces in Evolution, Is a creative force)
evolutionary adaptation
an accumulation of inherited characteristics that enhance organisms⬲ ability to survive and reproduce in specific environments
The process of which the form and overall genetic structures of organisms change over time.
Common opinion of 19th century
Species were immutable products of sudden creation
the branch of biology concerned with naming and classifying organisms (Carolus Linnaeus)He developed the two–part, or binomial, system of naming organisms according to genus and species that is still used today
the orgin of matter and of distinct species of animals and plants are due to acts of creation by God.
the study of fossils, was largely developed by French scientist Georges Cuvier (1769–1832)
(Cuvier) speculating that each boundary between strata represents a catastrophe, such as a flood or drought, that destroyed many of the species living at that time
Small scale changes, does not lead to new species
Large scale changes, lead to new species
the idea that profound change can take place through the cumulative effect of slow but continuous processes.
Lyell proposed that the same geologic processes are operating today as in the past, and at the same rate. IE: Vulcanism, Mt Bldg, Formation of water falls.
Darwins Evidences used to combat the static view of species (1)
Fossils in South America resemble animals on the Galápagos. He hypothesized that the Galápagos had been colonized by organisms that had strayed from South America and had then diversified on the various islands.
Darwins Evidences used to combat the static view of species (2)
Resemblances between living species. Mammals have common ancestor- each with different purpose, same bones arranged in the same order.
Adaptive Radiation
When ancestral animal adapt and change or adapt to local conditions. (Finches)
castaways from storms on drift wood.
descent with modification
a phrase that summarized his view of life. Darwin perceived unity in life, with all organisms related through descent from an ancestor that lived in the remote past. As the descendants of that ancestral organism spilled into various habitats over millions of years, they accumulated diverse modifications, or adaptations, that fit them to specific ways of life.
Nat Selection Info 1
Organisms vary and these variations at least in part are inherited by their offspring. Variations are passed
Nat Selection Info 2
Organisms produce more offspring then what can survive, Many going to be eaten, Diseased, weak genotypes
Nat Selction Conclusion
on average offspring that vary most strongly in directions favored by the environment will survive and propogate. Favorable variation will there for accumulate in population by natural selection.

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