16 JANUARY 201423_BIO130_0116141/16/2014Bio 130 Lecture 3 TR 12:40-1:55pBig quiz one week from today on Tuesday’s (1/14) material.Review class notes, complete review questions, read textbook, professor and TA office hoursEvolution by Natural SelectionEvolution and Information Flow and Storage, 2 of 5 Big IdeasObjectives:- List three requirements for natural selection- Describe how natural selection can cause a trait to evolve- Define adaptation Clicker quiz, no credit, just to test softwareSpecies is now seen as something can change over time, first proposed by Lamarck. Darwin is credited with the theory of evolution through natural selection. He did most of his research on the Galapagos Islands. Wallace and Darwin published their ideas together. Natural selection is only effective on traits expressed in the genes of a specimen. Dog breeders mate dogs with desirable phenotypes. For change to occur the phenotypes must be passed to the offspring through genes. DNA is the blueprint for how to build and maintain an organism. A gene is a portion of DNA that codes for a specific protein. Information flowGene  mRNA protein, DNA is packaged into chromosomes. Each human has 23 chromosomes. A genotype is a combination of alleles for a given gene in an individual. For eye color, there are three possible genotypes: BB, Bb and bb. BB, Bb – brown eyes, bb – blue eyes. Offspring inherit these genes from their parents’ gametes that are divided through meiosis. Half the chromosome comes from the egg, half from the sperm. Body size in dogs is caused by a growth factor. Possible alleles: I and B. II, BI = big dog, BB = small dog. When breeders were breeding small dogs, they were selecting for the B alleles. Phenotypes can also be determined by the environment. Identical twins can differ in appearance based on lifestyle. These traits caused by the environment are not passed to offspring. Evolution by Natural Selection will occur if:1. Variation: individuals in a population have variable phenotypes (traits).2. Heritability: phenotypic variation is heritable (passed on to offspring).3. Differential Reproduction: There is UNEQUAL reproductive success in the population and individuals with favorable traits are more likely to survive and produce more surviving offspring (have higher fitness)Natural selection is a two-step process.1. Heritable variation (e.g. speed)2. Individuals are selected (e.g. slowest gazelles are killed)3. The result is in the next generation (e.g. faster gazelles)16 JANUARY 2014Individuals are selected, populations evolveIn class assignment: After the drought, what change occurred in the Daphne Major Finch population?^This is the kind of question that will be on the big quiz and exams. 1. Before the drought occurred, there was variation in beak depth.2. Beak depth is heritable.3. During the drought birds with large beaks are more likely to survive and reproduce.Therefore, average beak depth increased in the next generation. Evolution is any genetic change in the