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Chapter 22 Bio

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Evolution
specific: a change over time in the genetic composition of a population; broad: populations change over generations
Aristotle and Scala Naturae
Viewed species as fixed and unchanged
The Old Testament
Species were individually designed by God, and thus perfect
Carolus Linnaeus
Developed taxonomy, which would classify the diversity of God
Georges Cuvier
Believed in catastrophism, and not in evolution
Explain the role of fossils in rock strata as a window to life in earlier times
Fossils are remains or traces of organisms from the past. Because rocks are in layers, time periods can be divided into such layers, and thus the gradual changes in creatures over time periods can be observed
How would Georges Cuvier have explained the appearance of the record of life shown in rock strata
Catastrophism: each boundary represents a catastrophe that destroyed many of the species at the time.
James Hutton
Gradualism: Earth's geologic features could be explained by gradual mechanisms currently operating in the world
Charles Lyell
Uniformitarianism: same geological processes are operating today as in the past at the same rate
What is the importance of uniformitarianism?
It implied that the world is much older than was believed at the time.
Use and disuse
Parts of the body that are used extensively become bigger and stronger; those not used would deteriorate
Inheritance of acquired characteristics
Organisms could pass on modifications (from use and disuse) to their offspring
What is considered to be the great importance of Lamarck's ideas?
The importance was that variation was introduced through inheritance
What are adaptations? Give two examples.
Characteristics of organisms that enhance survival. Differing beak variations, color of body (aposematic coloration)
Natural selection
Individuals with certain inherited traits leave more offspring than individuals with other traits
Variations in traits exist
large beaks v small beaks
Variations are heritable
Large beaked birds that reproduce with large beaked birds will most likely have large beaks
Species overproduce
e. Coli will divide non stop so long as they are moved to allow for more space and waste is removed
This competition for resources; not all offspring survive
Those HIV viruses that are not resistant to particular bacteria die out
What are two inferences that Darwin made?
1) Descent with modification explains life's unity and diversity. 2) Natural selection brings about the match between organisms and their environment
____ do not evolve, ______ evolve
Individuals... Populations
What is the role of 3TC in inhibiting HIV reproduction?
3TC is inserted instead of cytosine which inhibits gene expression because the genetic code cannot be used properly.
Do antibiotics cause bacteria to become resistant?
No, but it selects for resistant individuals
What are four evidences for evolution?
Fossil record, homologous structures, analogous structures, vestigial structures
How does the fossil record give evidence for evolution?
Past organisms differ from present day organisms and many species have become extinct
Example of Homologous structures
Bat wings and whale fins
Example of Vestigal structures
Snakes having vestiges of the pelvis and leg bones
Analogous structures
Sugar glider and the flying squirrel
How do homologous structures give evidence for evolution?
They imply a common ancestor from which the organisms evolved
What is summarized in an evolutionary tree
Evolutionary relationships among groups of organisms
What is indicated by branch points?
Common ancestor of the lineage
What is indicated by the hatch marks?
Homologous characteristics shared by the group
Are crocodiles more closely related to lizards or to birds?
Birds, both are amniotes
Explain convergent evolution and describe how analogous structures can rise
Independent evolution of similar features in different lineages is convergent evolution. Analogous structures can rise when different organisms from different lineage face similar problems
Two examples of convergent evolution
Sugar glider and flying squirrel; bird wing and butterfly wing
What is biogeography? How is it affected by continental drift?
Study of the biographic distribution of species. Continental drift makes continents shift which can make it more difficult to analyze biogeography.
Endemic species
Species that are found nowhere else on earth