(we’ll work as a class in 5 min.) WELCOME BACK!!! In Activity: Scent Lab Pick up Scent Lab by door & Read the Directions (we’ll work as a class in 5 min.)

Scent Lab Pretend you are a wolf and must find your pack using your sense of smell. Why is the adaptation of smell important to the survival and evolution of Wolf packs?

TEKS 7C Analyze and evaluate how natural selection produces change in populations, not individuals

Population Genetics Lab Clear your desk & Read the introduction Use the materials to model populations in various scenarios: Population, Natural Selection, Mutation, Reproductive Isolation, Gene Flow, Genetic Drift, Barrier Isolation Answer all questions on the handout Return the materials to your teacher Class Debrief

Concept Map Notes: Speciation Mutations Gene Shuffling Gene Flow (migrations) Genetic Drift (bottle neck effect & founder effect)

Emergence of Evolutionary Thought Galapagos Islands Charles Darwin 1809 - 1882

Voyage of the H.M.S. Beagle Darwin was 22 joined the crew of the H. M. S. Beagle as naturalist left England in 1831 arrived in the Galapagos Islands in 1835 collected specimens & recorded observations

Darwin’s Galapagos Observations: 1835 Darwin’s hypothesis: Perhaps all the species descended from the mainland finch, then changed slightly after becoming isolated on different islands.

Concept Map Notes: Speciation Mutations Gene Shuffling Gene Flow (migrations) Genetic Drift (bottle neck effect & founder effect)

Evolution: How It Works Mechanisms of Evolution: natural selection Mutation Non-random mating Population Genetics: Genetic drift Migration (gene flow)

Mechanisms of Evolution: Natural Selection V = Variation: All life forms vary genetically within a population. I = Inheritance: Genetic traits are inherited from parents and passed on to offspring. S = Selection: Organisms with traits that are favorable for survival get to live and pass on their genes to the next generation. T = Time: Evolution can happen in a few generations, but major change, such as speciation, often takes long periods of time. http://evolution.berkeley.edu

Mechanisms of Evolution: Natural Selection Natural Selection is determined by the environment.

Mechanisms of Evolution: Nonrandom Mating A preference by one sexual partner for a particular phenotype The result of nonrandom mating is that some individuals have more opportunity to mate than others and thus produce more offspring

Mechanisms of Evolution: Causes of Mutations 1. DNA fails to copy accurately 2. Environmental influences can cause mutations.

Mechanisms of Evolution: Population Genetics Important terms: Gene Pool consists of all genes including all the different alleles in population Relative Frequency of an allele is the number of times that the allele occurs in a gene pool. Single Gene Traits are controlled by a single gene that has two alleles

Mechanisms of Evolution: Genetic Drift p.400 Genetic drift is a change in a population’s allele frequencies due to chance. The smaller the population, the larger the effect. Bottleneck Effect Founder Effect Genetic Drift (2007) by Michael Dumas

Genetic Drift: Bottleneck Effect Disease, starvation, or some other disaster can nearly wipe out large populations. Even though the population recovers, the relative abundance of alleles has been randomly altered.

Genetic Drift: Bottleneck Effect Gene pool

Genetic Drift: Founder Effect p.400 A few individuals leave a population and establish a new one. By chance the allele frequencies for many traits may not be the same as in the original population.

Mechanisms of Evolution: Migration (gene flow) Movement of genes from one population to another. If genes are carried to a population where those genes previously did not exist, gene flow can be a very important source of genetic variation.

Evolution vs. Genetic Equilibrium Hardy-Weinberg Principle: allele frequencies in a population remain constant unless one or more factors cause those frequencies to change. (p.402) Genetic Equilibrium: allele frequencies remain constant (no change = no evolution).

Development of New Species: Speciation Speciation is the development of one or more species from an existing species. How does speciation occur? (p.404)

Speciation: How Does it Work? (p.404) Sometimes barriers arise between parts of a population and create local breeding units. Then, two or more gene pools exist when there was only one. Geographic isolation: populations can be separated by geographic barriers Reproductive isolation: any aspect of structure or behavior that prevents breeding (breeding seasons, behavior, etc)

Evidence of Evolution 1. fossil record 2. homologous structures 3. vestigial organs 4. developmental embryology 5. biogeography – different species are found in similar geographic regions 6. molecular (DNA) evidence – comparisons can be made between organisms

Evolution Simplified selection time genetic variation in individuals +

“OUT” Exit Ticket Explain 3 examples of how population genetics can affect the evolution of a population.

A Final Thought (read this quote & respond with your thoughts on paper) Evolution is not merely an idea, a theory or a concept, but it is the name of a process in nature, the occurrence of which can be documented by mountains of evidence that nobody has been able to refute. It is now actually misleading to refer to evolution as a theory, considering the massive evidence that has been discovered over the last 140 years documenting its existence. Evolution is no longer a theory, it is a fact.” Ernst Mayr Professor Emeritus Harvard University