What is Evolution?What is Evolution?• Variation exists in all populations• Variation is inherited
• Evolution is heritable changes in a population over many generations.
• Descent with modification • Evolution is change in allelic frequency
• Variation exists in all populations• Variation is inherited
• Evolution is heritable changes in a population over many generations.
• Descent with modification • Evolution is change in allelic frequency
Mechanisms of EvolutionMechanisms of Evolution• Natural Selection (Darwinism)
• individuals with favorable variations (traits) better survive and reproduce.
• The genes (inherited variation) of the successful individuals increase in frequency in subsequent generations.
Survival of the fittest
• Genetic Drift
• Natural Selection (Darwinism) • individuals with favorable variations (traits) better
survive and reproduce.• The genes (inherited variation) of the successful
individuals increase in frequency in subsequent generations.
Survival of the fittest
• Genetic Drift
Evolutionary Theory does not:
Evolutionary Theory does not:
• Propose the origin of life.“There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”
• Charles Darwin, 1859, The Origin of Species
• Specify a rate of evolution
• Propose the origin of life.“There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”
• Charles Darwin, 1859, The Origin of Species
• Specify a rate of evolution
Points to RememberPoints to Remember
• Populations Evolve• Individuals do not
• Mutations are random, selection is not
• Populations adapt to new environments
• Individuals acclimate
• Populations Evolve• Individuals do not
• Mutations are random, selection is not
• Populations adapt to new environments
• Individuals acclimate
SahiwalSahiwal
TharparkarTharparkar
Genotypic Frequencies of Indian Dairy Cattle
Genotypic Frequencies of Indian Dairy Cattle
AA = 0.031AB = 0.276BB = 0.693
AA = 0.023AB = 0.733BB = 0.244
What are the allelic frequencies of each breed?
Allelic Frequencies of Indian Dairy Cattle
Allelic Frequencies of Indian Dairy Cattle
A = 0.17B = 0.83
A = 0.39B = 0.61
What are the expected genotypic frequencies of each breed?
Expected Genotypic Frequencies of Indian Dairy Cattle
Expected Genotypic Frequencies of Indian Dairy Cattle
ExpectedAA = 0.029AB = 0.282BB = 0.689
How do you interpret these results?
ExpectedAA = 0.152AB = 0.476BB = 0.372
ObservedAA = 0.031AB = 0.276BB = 0.693
ObservedAA = 0.023AB = 0.733BB = 0.244
How would test for significance?
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χ 2 =∑Observed − Expected( )
2
Expected
