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Biology 3rd Block Room 128
Mr. R. Bair Biology Teacher
Mrs. MV Smith Resource Teacher
Date: November 21, 2007
Drill
Name 4 pieces of evidence, which support the theory of evolution.
Played
1.
2.
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5.
Fossil Record
Radiometric Carbon Dating
Comparative Anatomy
Comparative Embryology
Genetics
What’s the Evidence for Evolution?
Evolutionary Time Scales
Macroevolution long time scale events that create and destroy species
Darwin did not talk about the origin of things but the evolution of things (changes)
Microevolution
Short scale events (generation to generation) that changes the genotypes and phenotypes population
Change the frequency of alleles
Evidence for Evolution - The Peppered Moth Experiment:
(ex) Photographs of peppered moths naturally camouflaged while at rest upon tree trunks as evidence for natural
selection.
(crit) Biologists have known since the 1980's that peppered moths don't normally rest on tree trunks. The
Biology 3rd Block Room 128
Mr. R. Bair Biology Teacher
Mrs. MV Smith Resource Teacher
photographs found in the textbooks were staged using dead moths glued to tree trunks. (Jonathan Wells, Ph.D.,
"Second Thoughts about Peppered Moths," 1999: http://www.arn.org/docs/wells/jw_pepmoth.htm.)
Evidence for Evolution - Genetic Mutations:
(ex) Genetic mutations have been shown to cause variation within species.
(crit) Genetic mutations result in a net loss of genetic information. There is no naturalistic source for genetic
information (nor is there a naturalistic explanation for the existence of information). Genetic mutation simply causes
existing genetic information to become corrupted - genetic mutations follow a downward trend. For example, it is
universally agreed that wolves, coyotes, dingoes, jackals, foxes, and the hundreds of different domestic dog breeds
probably all came from an original pair of "dogs". This is "Variation within a Kind," NOT upward evolution from
simplicity into complexity as supposed by Darwin's theory of evolution. The variations are always in a downward
trend constrained by the genetic code (the dogs do not grow wings and learn to fly). No new genetic information is
added, genetic information is always lost: the original pair of "dogs" had all of the potential characteristics of all
their various progeny, while the descendants themselves have lost that same potential.
http://www.brentrasmussen.com/log/guest_post_where_is_the_evidence_for_evolution
The weak link in Darwin’s theory understood how traits were transmitted
The rediscovery of Mendel’s work and the development of population genetics in the first decades of the 20th
century greatly strengthen evolutionary theory, leading to the so-called synthetic theory
A population is a group of interbreeding organisms present in a specific location at s specific time.
The gene pool is all the alleles present in a population.
Pedigree of Queen Victoria's Descendants
The appearance of hemophilia as it emerged in Spain, Russia, and Prussia (Germany) can be traced by
following the family tree of Queen Victoria's descendants.
http://www.knowledgene.com/public/view.php3?db=gene_school&uid=35
Allele frequency is the frequency of a particular allele in the population.
Evolution: change in the frequency of alleles
In breeding-One form of Non-random Mating
Inbreeding occurs when related individuals mate.
Inbreeding reduces the proportion of heterozygote and increases the population of homozygous in a
population.
This is a bad idea when considering recessive
Biology 3rd Block Room 128
Mr. R. Bair Biology Teacher
Mrs. MV Smith Resource Teacher
Forces of the Allele Frequency Changes
Mutation is the only source of new alleles in a species.
Mutation provides the raw material of evolution
Mutation acting alone works too slowly to drive evolution
Age of earth 4.6 billion years
Forces of Allele Frequency Change
There is only one force that changes allele frequency so that population become better adapted.
This is natural selection
Survival of the fit enough
The story of the peppered moth
Industrial melanism in peppered moths is one of the most frequently used examples of natural selection in action. This is largely
because of its pedagogical simplicity -- it is a straightforward example that is visual and dynamic -- and its copious documentation.
Industrial melanism refers to the darkening of color that occurred in a number of species of insects following the Industrial
Revolution. This change appears to be related to the increase in pollutants in the environment. Before the Industrial Revolution,
individuals of the moth species Biston betularia (commonly called the "peppered moth") were predominantly white with black
speckles. By the end of the 1800s, they were predominantly charcoal grey. This change was well documented and led Tutt (1896) to
hypothesize that this change was a result of pollution- stained trees' affecting the camouflage potential of the moths. This change
was termed "industrial melanism." In the 1950s, Bernard Kettlewell decided to test the hypothesis that natural selection was
working on the differential camouflage of the moths. In order to do this, he released marked light and dark moths into polluted and
non-polluted forests. He found that birds appear to prey selectively on light moths in polluted forests and on dark moths in nonpolluted forests and so documented the idea of natural selection of these color patterns in moths by birds. After anti-pollution laws
took effect and the bark lightened, the moth populations in formerly polluted areas returned to previous color distributions.
http://www.natcenscied.org/icons/icon6moths.html
Kettlewell’s moths
Gene Flow or Migration
Gene flow makes separate populations more similar genetically
Gene flow: Random movement of genes in a population
Genetic Drift is the random fluctuation in allele frequency between generation. Its effects are pronounced in
small proportions
1. This process supplies the new genetic material for
evolution
2. Long term time scale events which crate an destroy
c. Mutation
B. Macroevolution
Biology 3rd Block Room 128
Mr. R. Bair Biology Teacher
Mrs. MV Smith Resource Teacher
species
3. Short term events which change frequency of
alleles/genotypes and traits/phenotypes
4. Movement of genes into or out of a population
5. chance occurs which change the frequency of alleles
A. Microevolution
E. Gene Migration
D. Genetic Drift
Traits
Polygenic traits- bell curve
Size of anything
Leg length
http://fig.cox.miami.edu/~cmallery/150/mendel/polygenic.jpg
http://www.algebralab.org/img/49ab8f77-f675-423a-b8af-d46874987ab3.gif
directional selection
http://www.anselm.edu/homepage/jpitocch/genbios/23-12ModesOfSelection-L.gif
Biology 3rd Block Room 128
Mr. R. Bair Biology Teacher
Mrs. MV Smith Resource Teacher
Vestigial
Galapagos island