10.4 Evidence of Evolution The Evolution of Whales Pg. 318 (Sponge # 5) Please read the evidence on pg. 318 showing how whales evolved over time 1) Fossil Evidence: How had the Dorudon (40 million years ago), Ambulocetus (50 million years ago), and Pakicetus (52 million years ago) changed over millions of years? How are they similar and different than today’s whales? 2) Embryological Evidence: Looking at the whale embryo, please explain how the nostrils differ in whales from other land mammals. 3) Vestigial Evidence: Looking at the vestigial evidence, explain why whales have a femur and pelvis.

11.1 Genetic Variation Within Population KEY CONCEPT A population shares a common gene pool.

11.1 Genetic Variation Within Population Do you see any variation in this population of penguins? How is human variation different? Can you think of another animal that has very little variation? One with a lot of variation?

11.1 Genetic Variation Within Population Genetic variation in a population increases the chance that some individuals will survive. Genetic variation leads to phenotypic variation. Phenotypic variation- is any observable characteristic or trait of an organism (you can see it!) –color, size, looks

11.1 Genetic Variation Within Population Phenotypic variation is necessary for natural selection. –The greater the variation in phenotypes, the more likely it is that some individuals can survive in a changing environment Ex: The Peppered Moth Moths after pollutionMoths before the pollution

11.1 Genetic Variation Within Population Genetic variation is stored in a population’s gene pool. A gene pool is made up of all alleles in a population –allele combinations form when organisms have offspring

11.1 Genetic Variation Within Population Allele frequencies measure genetic variation. –measures how common allele is in population –can be calculated for each allele in gene pool

11.1 Genetic Variation Within Population Attached earlobes Tongue rolling Hitchhikers thumb

11.1 Genetic Variation Within Population PHENOTYPE ACTIVITY Attached Earlobes Tongue RollingHitchhiker’s Thumb YES NO Total Population

11.1 Genetic Variation Within Population SPONGE Why does genetic variation increase the chance that some individuals in a population will survive? (Think Peppered Moth)

11.1 Genetic Variation Within Population MUTATIONS

11.1 Genetic Variation Within Population A Mutation is a random change in the DNA of a gene. – can form new allele – can be passed on to offspring if in reproductive cells UGUAC AUG UAU ACG UCU CAA UGUAC AUG UAU ACG UCU CAG

11.1 Genetic Variation Within Population Mutations- Can be positive, neutral, or negative. Whether it is positive or negative depends on the environment CCR5-Δ32- gene found in some European people, but not in any South African people

11.1 Genetic Variation Within Population Genetic variation comes from several sources. Hybridization is the crossing of two different species. –occurs when individuals can’t find mate of own species –topic of current scientific research Liger= lion and tiger Tigon=Tiger and lionMule= horse and donkey

11.1 Genetic Variation Within Population Recombination forms new combinations of alleles. – usually occurs during meiosis – parents’ alleles arranged in new ways in gametes –-method of DNA repair *Can lead to offspring having a different combination of genes than their parents