Evolution Cont

Evolution Cont - Evolution Cont Tuesday, March 24, 2009...

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Evolution Cont Tuesday, March 24, 2009 9:31 AM 1. Drug Resistance evolution that can see everyday o Artificial Selection 2. Most that we see going on in our lifetimes are natural selection o Tomatoes o Plants 3. Conditions for Microevolution o Founder effect (not large) Small populations, may lose alleles. Definite change in organism over time. o Gene Flow (not isolated) Alleles coming and going o Mutations Form new alleles o Nonrandom Mating Certain ones selected o Natural Selection One that think about most often If these conditions that promote change, useful for people examining allele frequencies to examine situations with no change. 4. Hardy-Weinberg equilibrium violations o 1=1 p 2 + 2pq + q 2 o Describes equilibrium Conditions for equilibrium Large population Population isolated No mutational change Random mating All types equally successful (no selection) o 1=p 2 + 2pq + q 2 o Group of Mongoose. Have trait with 2 alleles. Short tails and long tails. o L= long tails o l= short tails o p=60% of all alleles in population = L 100%=L + l o q=40% = l o 100%=p+q o 1=p+q o .6p .4q .6p .36p2 .24pq
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.24pq .16q2 o 100%=p 2 +2pq+q 2 o 2 alleles p and q o 36% of p, 48% (24% p, 24% q), 16% q o 60% p 40% q o Allele formation stay same o .16 = q 2 o .4=q .6=p if can count homozygous recessive can figure out the rest. o People take percentage that have disorder, take square root, equals frequency of people that have allele in population. o Half of people with a disorder die before reproduction. Tells q 2 is gonna get smaller, P is gonna get bigger. o If frequency of one allele decreases, frequency of another allele increases. o On test should be able to work problem. o Might give percent 5. Examples of Selection- - change from generation to generation o Balancing Polymorphism More than one form From balancing selection for/against alleles Maintains two forms (alleles) because each is favored under different conditions Selection for this one, selection for this one. Selection against one, selection against one Sickle Cell Anemia Malaria SS Ss have some misshaped red blood cells, but are ok. Sickle Cell Disease ss In countries with malaria, molaria parasites spend time in red blood cells. People with SS die of Malaria, ss die with Sickle Cell. If Ss survive get 1:2:1, selection against both alleles. Balancing Polymorphism o Snail Shell Color o Shells different o Certain areas where most of snails have different color o When hatched color equal in frequency o Color of sand/rock change o Ones that look like background lived, ones that didn’t were plucked up o Selection factor-- predators Bird drops shells Both alleles selected for or against in any population
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This note was uploaded on 11/05/2011 for the course BIOL 101 taught by Professor Hogan during the Fall '08 term at UNC.

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Evolution Cont - Evolution Cont Tuesday, March 24, 2009...

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