EVOLUTION

A. Evolution is a STRONGLY supported theory…. lots of evidence! the genetic change in a species over time. *** occurs in a population NOT IN INDIVIDUALS! B. Evolution is I. Introduction & Famous Theorists

C. Famous Theorists: 1. Jean-Baptiste Lamark (1809) a)Use and Disuse: organisms evolve because they needed to adapt to changes in environment b) Inheritance of Acquired Traits: useful traits developed during an individual’s lifetime are passed on to its offspring Ex. If you cut off your left hand… your kids won’t have one either

2. August Weismann (early 1900s) a) Disproved Lamark’s theory by cutting off the tails of mice for 50 generations. You could say I am a …..wise…..man…… *surprisingly… every generation grew tails. Well that’s just not cool!

I’m the man.

a) English naturalist. b) Travelled around the world on the HMS Beagle 3. Charles Darwin (mid-1800s) c) He studied and collected many organisms

d) On The Origin of Species (1859) * Darwin’s book e) Natural Selection: Overpopulation -More offspring are born than can possibly survive Competition -These offspring must compete for limited resources

Variation - Adaptation - Slight differences occur among members of the population (Caused by mutations and genetic recombination/crossing-over during meiosis) Variation that causes some individuals to have a greater Fitness (ability to survive and reproduce) than others. So… close… I’m better than you. Mmm… This tree is delicious… Curse this short neck! Survival of the Fittest -

Individuals who are more fit for their environment are more likely to survive and reproduce to pass on their favorable traits. Less fit individuals die and their unfavorable traits are eliminated from the gene pool Survival of the Fittest - Speciation - Many changes ultimately produce new species better adapted to an environment

Early fox population Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Gray Fox Arctic Fox Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward and separates Southern population Northern population Fig. 5.8, p. 113

*Examples of Natural Selection 1) Galapagos Island Finches Distinct differences (beak sizes and shapes) among birds on different islands Selecting agents = varying foods the finches ate.

2) Peppered Moth (in England) Two varieties: light-colored and dark-colored Pre-industrialization: light-colored moths blended in with light tree bark  more light moths than dark moths Post-Industrialization:  soot covered trees  Dark moths have advantage

3) Insecticide-resistant Insects & Antibiotic-resistant Bacteria Insecticides kill most insects, while some insects are resistant to the insecticide & live to reproduce (Insecticide acts as a selecting agent) Antibiotic kills most bacteria, while resistant bacteria live to reproduce. (Antibiotic is selecting agent) A natural variation existed which allowed some insects/bacteria to survive exposure to insecticide/antibiotic (selecting agent) and reproduce

II. Evidence of Evolution A. Fossils: preserved remains or evidence of an ancient organism * Whole organism, bones, teeth, footprint, leaves, etc. * Fossils form by layering of sedimentary rock Oldest Recent

B. Evidence in Living Organisms 1) Comparative Anatomy: structural similarities Homologous structures: similar form but different function Vestigial structures: remnants of structures that used to be useful Ex. Appendix

2) Comparative Embryology: closely related species have similar patterns of development *Common ancestor

3) Comparative Cytology: similarities in cell structures 4) Comparative Biochemistry: closely related organisms have similar DNA and proteins Ex. human vs. ape hemoglobin

III. Causes of Evolution: 1. Mutations 2. Sexual Reproduction: Crossing over A. Sources of Genetic Variations B. When two populations are isolated from one another… Natural selection might affect them differently, leading to new species.

Geographic Isolation…

Behavioral Isolation

*Adaptive radiation* Period of evolutionary change in which groups of organisms form several new species with adaptations to fill different niches in the community.

Galapagos Island Finches Similarities among all of the species, both on the mainland and the islands Distinct differences (i.e. beak sizes and shapes) among those on different islands, which Darwin attributed to the selecting agents of the varying foods the finches ate.

C. Things to remember: Evolution is a change in a population over many generations Natural selection doesn’t act directly on genes- it acts on phenotypes by determining which traits (alleles) are passed on.

D. Theories of Evolution Patterns: GradualismPunctuated Equilibrium Vs. *evolution is slow, gradual, and continuous. *long periods of little or no change are interrupted by short periods of rapid change. Common Ancestor Common Ancestor Past Present Past Present

1.Early Hypotheses a. Creationism E. The First Cell(s):

b. Spontaneous Generation: life arises from nonliving matter Aristotle, Virgil

Redi’s Experiment

Pasteur’s Experiment

a. Primordial Soup:Early Earth was covered in hot water with various chemicals dissolved in it organic compounds formed through random bonding the first “cell” consumed other materials and divided …a heterotroph! 2. Heterotroph Hypothesis (Modern Hypothesis)

Miller-Urey Experiment

b. The first life forms were anaerobic. Autotrophs evolved, releasing oxygen into the atmosphere, allowing some life forms to evolve and become aerobic