GENES AND EVOLUTION Unit Eight

Principles of Evolution 1)Genetic variety ◦DNA mutations-adds new phenotypes to a population ◦Genetic recombination (crossing over) allows for variety 2)Mutation and Environment ◦New phenotype either “fits” or doesn’t “fit” with environment ◦Those that fit best are more likely to reproduce and survive (natural selection) 3)New Species Evolve ◦Mutations and natural selection result in a new species over millions of years

Difference between Natural Selection and Evolution: Natural selection drives evolution

Today’s Focus ◦DNA mutations: ◦Brings in new alleles ◦Adds new phenotypes to a population ◦Allows organisms to adapt to their environment

Sequencing Neanderthal DNA 1.Why is comparing human DNA to Neanderthal DNA difficult in the lab? 2.How can the bases of DNA change overtime? 3.Where was the sample taken from Pääbo found and how old was it? 4.What did the lab results say about the population size of Neanderthals? 5.How many Neanderthals did Paabo sequence and where were they from? 6.Was the Neanderthal DNA genetically diverse? 7.How does the DNA differ between modern humans and Neanderthals? 8.What percent of DNA changed after humans split from Neanderthals?

Sequencing Neanderthal DNA

Thursday Assessment Question How do DNA mutations give rise to new species over millions of years? Notebook Checklist Evolution foldable Neanderthal questions

GENES AND EVOLUTION Unit Eight

Which of the following best describes evolution? a.Changing of organisms over time b.The descent of an organism from a common ancestor c.Phenotypes of an organism and how they fit with the environment d.Both a and b

Which of the following is the most necessary in order for evolution to happen? a.Organisms need to have selective pressure b.There needs to be a common ancestor c.Phenotypes need to be successful d.There must be genetic mutations

What is the difference between a gene and a phenotype? a.A gene is a sequence of DNA and a phenotype is the gene expression b.A gene is a protein and a phenotype is DNA c.A gene is a sequence of DNA and a phenotype is the physical protein expression d.I don’t know

Gene Frequency ◦Indicates which genotypes are most prevalent or least prevalent in a population ◦Calculated as a percent ◦# in population/total

Gene Frequency ◦Brown- AA ◦White-aa What is the genotypic frequency for homozygous recessive?

Beetle Genotypic Frequency Lab Purpose Explore the genotypic frequency in a beetle population Connection to Learning Objective How does a changing in genotypic frequency result in evolution? Friday Assessment Question How did a change in genotypic frequency cause your beetle population to evolve?