Transcript IV. Diversity of Life

IV. Diversity of Life
http://cache.eb.com/eb/image?id=6535&rendTypeId=4
A. Micro evolution:
1. evolution on the smallest scale
2. generation to generation change in
frequencies of alleles
http://evolution.berkeley.edu/evosite/evo101/images/micro_mech_3.gif
B. Gene Pool:
1. consists of all the alleles in all individuals
that make up a population
2. reservoir where next generation draws it
genes from
3. where genetic variation is stored
http://www.brooklyn.cuny.edu/bc/ahp/LAD/C21/graphics/C21_GenePool_2.GIF
C. Changes in the Gene Pool:
1. Natural Selection is not random
2. Environment favors genetic
combinations & contribute to survival and
reproductive success
3. some alleles may become more
common
4. changes in
frequency of alleles
http://biology.unm.edu/ccouncil/Biology_203/Images/PopGen/bugflow.gif
D. Hardy-Weinberg Equilibrium
1. Population that does not undergo change in
gene pool
2. Are not presently evolving
3. Frequency of gene pool is constant
4. Rarely occurs for long period of time in nature
5. Provides “no change” baseline for comparison
http://biology.unm.edu/ccouncil/Biology_203/Images/PopGen/nonrandom.jpeg
E. Changes to the Gene Pool?
1. Genetic drift: a change in the gene
pool of a population due to chance
2. Natural Selection
Genetic drift: When the beetles
reproduced, just by random luck
more brown genes than green
genes ended up in the offspring.
http://images.google.com/images?um=1&hl=en&q=genetic+drift
Natural selection: Beetles with brown
genes escaped predation and survived
to reproduce more frequently than
beetles with green genes, so that
more brown genes got into the next
generation.
F. Macro Evolution
1. More dramatic biological changes
2. Evidence found in fossil records
3. Includes:
a. Origin of different species
b. Extinction of species
c. Evolution of major new features of living things
http://evolution.berkeley.edu/evosite/evo101/VIADefinition.shtml
http://www.talkorigins.org/faqs/macroevolution.html
4. Speciation:
a. The origin of new species
b. Biological diversity
c. Increase in number of species
http://www.virtuallaboratory.net/Biofundamentals/lectureNotes/AllGraphics/SpeciesBeaks.jpg