1. Evolution is a change in the hereditary features of a population over time Adaptations are traits that make organisms better able to survive Mutations are the source for new traits Ideas of the Time 1. Georges Buffon suggested: The Earth is much more than 10,000 years old Fossils were similar and different to living animals 2. Jean Baptiste Lamark proposed inheritance of acquired characteristics Giraffe necks lengthen by stretching over time Mistaken explanation The Voyage of Charles Darwin 1. Charles Darwin voyaged around the world on the HMS Beagle Gathered plant and animal specimens Made observations on the Galapagos Islands Read about gradual geological processes that shape the Earth 2. Wrote The Origin of Species which explained his “theory of evolution” Natural Selection The Origin of Species 1. Descent with modification Organisms living today descended from ancestors They accumulated modifications to diverse ways of life 2. Natural selection: something in the environment determines if an organism will survive to have offspring Overproduction- more organisms are produced than can survive Variation- different traits found in a population Completion- struggle to survive, compete over resources “Survival of the fittest”- only the strongest survive, mate, and produce offspring with string traits Speciation- evolution of species with adaptations Artificial Selection 1. Artificial Selection: humans determine if an organism will survive to have offspring selective breeding of domesticated plants and animals Selection in Action

1. Natural selection and evolution can be observable events Pesticide resistance in insects The peppered moth on Manchester Evidence of Evolution Geological Evidence

2. Fossils Preserved remain of once living organisms (extinct) footprint, leaf imprint, bones, insect in sap 2. Sedimentary rock Forms from layers of mud, sand, other, small particles Fossils form in these layers Oldest in bottom layers, youngest in top layer Selection

3. Similarities in development Comparison of embryos Many animal embryos look very similar 2. Comparison of DNA All organisms have DNA More similar organisms have more similar DNA 3. Comparison of structures Homologous- similar in structure Inherited from a common ancestor Example: arm of human and cat Analogous- similar in function Not inherited from a common ancestor Example: wing of butterfly and bird Vestigial- no longer has a function Inherited from an ancestor Examples: appendix of human, wings of an ostrich Mechanisms of Selection Hardy- Weinberg’s Gene Pool

   1. A gene pool consists of all the alleles of all the individuals in a population

4. Microevolution is a change in a population’s gene pool

5. Hardy- Weinberg equilibrium: no change in gene pool = no evolution

6. Changes in population can arise by: Genetic drift Gene flow Nonrandom mating Mutation Natural Selection Genetic Drift

   1. Genetic drift is a change that occurs by chance in a small gene pool Bottleneck effect- a disaster (fire) leaves only a few to reproduce Founder effect- a few individuals colonize an isolated area (island) Gene Flow & Mutation

   2. Gene flow is due to migration of fertile individuals into or out of a population

   3. Nonrandom mating includes inbreeding and the selection of mates with specific phenotypes

7. A mutation is a random change in an organism’s DNA that creates a new allele The original source of variation The Evolution of Health Evolution of Sickle Cell

   1. Sickle cell affects 1 in 25 in parts of Africa Suffer pain, organ damage even death

8. Individuals with one copy of the gene (32%) are resistant to malaria Antibiotic Resistant Bacteria

   1. Antibiotic kill or slow the growth of bacteria

   2. Resistant to antibiotics evolves by natural selection Tuberculosis (TB)

   3. We must prevent overuse of these drugs