1	History of Life & Evolution Biology & PreAP Biology PAK 8
2	Measuring Earth’s Age The age of the Earth has been measured using a technique called radiometric dating. Technique uses half-life of various radioisotopes Both are discussed in visual concepts for this chapter. See link Earth’s Age on the Visual Concepts Tab (Ch. 12) on Holt website
3	Formation of Basic Chemicals of Life Two Models are currently accepted: The “Primordial Soup” Model The Bubble Model See link for Spontaneous Origin on the Holt website under Ch. 12 Visual Concepts
4	Evolution of Cellular Life Evolution of Eukaryotes Developed from prokaryotes Chloroplasts and mitochondria developed through endosymbiosis
5	Charles Darwin- Father of evolution 19th century English naturalist Went on a voyage on HMS Beagle On his trip, he read books by many people and proposed theory of evolution in book “Origin of Species”
6	Formation of the Theory Influenced by: Charles Lyell-English geologist Thomas Malthus-English economist, naturalist Observed: Diversity in living things Fossils formations Adaptation Fitness Homologous Structures
7	Theory of Evolution Natural Selection- Individuals that are better adapted to their environment will survive and reproduce more often than individuals that are not as well adapted. Defined as change over time. Has become unifying principle of biology
8	Support of Evolution Inherited variation exists within the genes of every population or species (the result of random mutation and translation errors) In a particular environment, some individuals of a population or species are better suited to survive (as a result of variation) and have more offspring (natural selection). Over time, the traits that make certain individuals of a population able to survive and reproduce tend to spread in that population. There is overwhelming evidence from fossils and many other sources that living species evolved from organisms that are extinct.
9	Darwin “Meets” DNA Gregor Mendel Demonstrated that genes are carriers of inheritable traits. Inheritable variation comes from changes in an organism’s genetic material
10	The Role of Chance in Evolution Genetic drift- random changes in the allele frequency of a gene pool. Most likely to occur in small populations. Can lead to speciation- the formation of a new species. Changes (adaptations) become so severe that groups can no longer interbreed successfully.
11	Genes, Fitness, & Adaptation Evolutionary fitness-success in passing genes to the next generation. Adaptation-genetically controlled traits that increases the ability to survive and pass along copies of these genes All species draw from the same gene pool-all the alleles shared by individuals of a species. Evolution occurs due to changes in the relative frequency of alleles in the gene pool of a species.
12	The Pace of Evolution Darwin believed that evolution occurred slowly. Called gradualism. More recent research shows evolution to occur in fits and starts. Known as punctuated equilibrium. This involves long periods of stability that are interrupted by episodes of rapid change.
13	Evidence of Evolution The fossil record Shows a pattern of development from early ancestors to modern descendants.
14	Evidence of Evolution Homologous structures Vestigial structures
15	Evidence of Evolution Scientists have also used comparison of : Proteins (ex. Hemoglobin) DNA Sequences (more exact comparison between organisms that are closely related)