2. What is Evolution? In biology, evolution is the change in the inherited traits (a.k.a. genes/alleles, genotypes/phenotypes) of species (or populations of a species) over time. Throughout this unit, you will see that three main processes determine the rate of evolution: –1) variation within a species (i.e. the fact that no one is an identical clone to another person) –2) reproduction: the method of reproduction and the rate at which a species reproduces will affect how fast it evolves. –3) selection: whether natural selection or sexual selection, you will see that those best suited to their particular environment will pass on their genes more frequently.

3. Evolution by Natural Selection The most famous explanation of evolution was made by Charles Darwin, who stated that those organisms best suited to their environment will be more successful at passing on their traits to the next generation. This he called Evolution by Natural Selection.

4. Darwin’s Influences Charles Darwin did not foresee himself getting into the field of evolutionary biology. He wanted to be a doctor like his father, but he could not stand the sight of blood and the savagery of surgery. He then wanted to be a minister, but he did not want to study. He preferred riding and shooting to studying. He eventually became interested in biology through his fascination with such exciting animals as barnacles, beetles and pigeons.

5. Darwin’s Influences He changed his path at college and took more biology courses as he developed a great love of taxonomy (yes, the classification stuff we did in the first unit) and studied intensely under the tutelage of botany professor John Stevens Henslow. Henslow recommended Darwin for work as an unpaid naturalist on a voyage around the world upon the HMS Beagle, under captain Robert Fitzroy. As you will see, this journey not only changed Darwin’s life, but also the face of biology forever…

6. Adaptation and Variation Organisms face constant environmental challenges that limit their ability to survive –Weather –Famine –Competition (food, space and mating) Organisms must survive long enough to pass along to offspring the genetic information that helped them survive If not, species will eventually become extinct Species do not “choose” to adapt, They either adapt or die!

7. Adaptation and Survival Adaptation is a structure, behavior, or physiological process that helps an organism survive and reproduce in an environment Camouflage hibernation

8. Camouflage

9. Mimicry

10. Mimicry: A type of Structural Adaptation A harmless species resembles a harmful species in coloration or structure Viceroy mimics Monarch. Monarch is toxic, Viceroy is not, birds avoid both

11. Development of Adaptations Result of gradual accumulative changes that help an organism survive and reproduce Random heritable mutations in DNA Variations are structural, functional differences between individuals of the same species Not all variations become adaptations

12. Peppered Moth: Variation to Adaptation Pre Industrial RevolutionAfter Industrial Revolution

13. The English Peppered Moth http://www.youtube.com/watch?v=LyRA807djLc

14. In Class Work Pg 299, Q 1-6

15. Variation Within Species Why is there so much variation Amongst members of human species? Genetic variation in a population results from the variety of genetic information in all individuals of the population

16. Mutations lead to genetic variation Mutations are a permanent change in the genetic material Provide new alleles in a species and source of new genetic variation when inherited Can occur spontaneously or through mutagens (UV, cigarettes, X-rays) Most mutations are benign or harmful

17. Mutations in gamete cells If a mutation occurs in a somatic cell, it disappears from the population when the organism dies. If mutation is in gametes, can be passed to future generations as a new allele

18. Mutations can provide a selective advantage If a mutation is beneficial it becomes a selective advantage; improves an organisms chance of survival Individuals living in malaria-plagued regions have a selective advantage of what genotype?__________

19. Rapid reproduction and selective advantage Some bacteria can double their population in under 10 minutes! Rapid reproduction means that an allele that was insignificant in the population may provide a selective advantage when the environment changes http://www.youtube.com/watch?v=UxHacm6gA0c

20. Antibiotic Resistance Activity 7.2, pg 302 Thoughtlab pg 312 (Due Wed May 2) all the questions up to extend further