BIOL 1202 Chapter : Chapter22Notes
Descent with Modification: A Darwinian View of Life
Chapter 22
I. What is Evolution & Adaptation?
a. Evolution: two main ideas
i. Change over time of the genetic composition of a population
ii. Decent of modern organisms with modification from preexisting
organisms
b. Evolutionary Adaptation
i. Accumulation of inherited characteristics that enhance organisms’
ability to survive in specific environments [look at the traits of an
organism; some of the traits help them to survive & reproduce
than other organisms, so it has more offspring with more
concentrated traits]
II. Pre-Darwinian Theory of Evolution
a. Lamarck
i. Use & disuse
1. Bodies of living organisms are modified through the use or
disuse of parts
ii. Inheritance of acquired characteristics
1. These modifications are inherited by offspring
iii. These ideas turned out to be wrong
III. Evolution by Natural Selection
a. Darwin & Wallace developed the theory independently
b. Darwin—voyage of the Beagle
i. Given the most credit
c. Wallace—naturalist in Indonesia
IV. Natural Selection
a. The unequal survival & reproduction of organisms due to environmental
forces, resulting in the preservation of favorable adaptations [looking at a
population, some organisms will have traits that allow them to survive &
reproduce, and those organisms will pass on more of those traits to the
next generation, which will alter the gene pool in that next generation]
b. Process “selects” from what is available in the gene pool
c. New characteristics are not created on demand
d. Mechanism Behind Natural Selection
i. Observations: Individuals in a population vary in their heritable
characteristics. & Organisms produce more offspring than the
environment can support.
ii. Inferences: Individuals that are well suited to their environment
tend to leave more offspring than other individuals. & Over time,
favorable traits accumulate in the population.
Document Summary
Descent with modification: a darwinian view of life. Ii: lamarck, use & disuse, bodies of living organisms are modified through the use or disuse of parts, inheritance of acquired characteristics, these modifications are inherited by offspring, these ideas turned out to be wrong. Evolution by natural selection: darwin & wallace developed the theory independently, darwin voyage of the beagle, given the most credit, wallace naturalist in indonesia. & organisms produce more offspring than the environment can support: inferences: individuals that are well suited to their environment tend to leave more offspring than other individuals. & over time, favorable traits accumulate in the population: clicker: within a few weeks of treatment with the drug. 3tc, a atietns hiv population consists almost entirely of. A few drug resistant viruses were present at the start of treatment, and natural selection increased the number. Artificial selection: selective breeding of organisms to encourage the occurrence of desirable traits, analogous to natural selection.
