Notes - Chapter 22- Descent with Modification: A Darwinian...

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Chapter 22- Descent with Modification: A Darwinian View of Life What is evolution and adaption? Two Main ideas o Change over time of genetic composition of a population o Decent of modern organisms with modifications from preexisting organisms Evolutionary Adaption o Accumulation of inherited characteristics that enhance organism’ ability to survive in specific environments Pre-Darwinian Theory of Evolution Lamarck o Inheritance of acquired characteristics Bodies of living organisms are modified through the use or disuse of parts These modifications are inherited by offspring This idea turned out to be wrong Evolution by Natural Selection Darwin and Wallace developed the theory independently o Darwin Voyage of the beagle o Wallace Naturalist in Indonesia Natural Selection The unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations Process “selects” from what is available in the gene pool New characteristics are not created on demand Mechanism Behind Natural Selection- Pg. 458 Not every animal lives (some that do may not reproduce) Population tends to grow exponentially
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Populations in nature remain constant (only so much food/water) limited survival o Leads to competition among animals fight for food o Fight for attractive mates o Survival Skills Artificial Selection Selective breeding of organisms to encourage the occurrence of desirable traits Analogous to natural selection Concept 22.3- Evolution is supported by an overwhelming amount of scientific evidence (Fig 22.13) Fossil Record (Fig 22.15) Show the change in organisms through time Change in types of organisms o Past organisms differ from present day organisms o Many species have become extinct Homologous and Analogous Homologous Structures (Fig 22.17) o May differ in function, but have similar anatomy Analogous Structures o Have similar functions and superficially similar appearance, but different anatomies (convergent evolution) Homologous Structures (Fig. 22.19) Vertebrate Embryos (Fig. 22.18) o All vertebrates share similar development genes o Differences arise by some genes being expressed differently Biochemistry and Molecular biology o DNA is universal genetic material o All life forms use approximately the same 20 amino acids to make proteins o All use ATP as primary form of cellular energy
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o All use RNA and ribosome to make proteins Biogeography Geographic distribution of species o Closely related species tend to be found in the same region
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Notes - Chapter 22- Descent with Modification: A Darwinian...

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