Laboratory_12_Population_Genetics_and_Natural_Selection

Laboratory_12_Population_Genetics_and_Natural_Selection -...

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Unformatted text preview: Laboratory 12: Population Genetics & Natural Selection Genetics Objectives Objectives To understand the difference between To individual human genetics and genetics of populations populations Concept of gene frequencies changes Understand Darwin’s concept of natural Understand selection selection Understand the concept of random genetic Understand change in populations change Charles Darwin, we hardly knew ye (1809 – 1882) (1809 English Naturalist Developed the concept of Developed natural selection natural Spent five years on the Spent Beagle Beagle His ideas were His controversial controversial Worked with botanists Worked and animal husbanders to give evidence to gain public approval public Charles Darwin (cont.) Charles On The Origin Of Species By Means Of Natural On Selection (1859) (1859) Established evolution by common descent as Established the dominant scientific explanation of diversification in nature Darwin’s Theory of Darwin’s Natural Selection 1. Organisms tend to multiply at a geometric rate. Darwin’s Theory of Darwin’s Natural Selection 1. Organisms tend to multiply at a geometric rate. 2. The number of individuals in a population remains 2. remarkably constant. Darwin’s Theory of Darwin’s Natural Selection 1. Organisms tend to multiply at a geometric rate. 2. The number of individuals in a population remains 2. remarkably constant. 3. Therefore a struggle for survival results. Darwin’s Theory of Darwin’s Natural Selection 1. Organisms tend to multiply at a geometric rate. 2. The number of individuals in a population remains 2. remarkably constant. 3. Therefore a struggle for survival results. 4. Variations exist among the members of a population. Darwin’s Theory of Darwin’s Natural Selection 1. Organisms tend to multiply at a geometric rate. 2. The number of individuals in a population remains 2. remarkably constant. 3. Therefore a struggle for survival results. 4. Variations exist among the members of a population. 5. Individuals with favorable variations will survive to 5. produce offspring. produce Lateral Thinking Lateral "You cannot dig a hole in a different place by digging the same hole deeper" by This means that trying harder in the same direction may not be as useful as changing direction. direction. Effort in the same direction (approach) will not necessarily succeed. not Organisms Do Not Evolve, Populations Do Populations Evolution & Natural Selection Evolution Individuals genetics cannot change Populations over time can change Selection pressures by the environment cause Selection natural selection to occur natural These can include temperature, food availability, These climatic change, etc. climatic H.B.D. Kettlewell & Peppered Moths Moths Conducted his experiments in England Conducted after the Industrial Revolution (1950’s) after Marked hundreds of moths in an Marked industrialized area & a rural area industrialized Found that in industrialized areas the dark Found moths were more prominent & light moths in the rural area: Why? in Answer: Birds Artificial Selection Artificial Human induced selection Breeding of Animals Pesticides, herbicides, insecticides, etc. Antibiotics Experiment #1: Mating with No Selection Pressure Selection Everyone starts out heterozygous You mate with one person for each You generation, and no more generation, You mate only when I tell you to DO NOT mate ahead & everyone must DO mate in every generation mate You can not mate with the same individual You twice in a row twice Cheesy Pick-Up Lines: Selection Pressure? Pressure? Damn girl, you have more curves than a race track. Damn Is that the sun coming up... or is that just you lighting up my world? Is your last name Gillete cause your the best a man can get. get. You have a onion butt...... it makes me want to cry. Experiment #2: Mating with Selection Pressure Selection Same experiment as before, however Same homozygous individuals do not mate in the next generation next If you are homozygous recessive, you die If and need to pick again. and A human case of this would be Tay-Sachs human disease, a disease that causes nerve deterioration and death occurs before the age of 5 age Allelic Frequencies Allelic Complete tables 12.3 and 12.4 to Complete determine how many of each allele are present in each generation present Do they differ? Why? ...
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This note was uploaded on 08/08/2010 for the course BIO 100 taught by Professor Dr.dave during the Spring '08 term at E. Kentucky.

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