Evolution  Fossil Records Remains or traces of organisms that lived in the past Usually found in sedimentary rocks

Evolution  Organism buried soon after death and the hard parts become fossilized  Fossils indicate a great deal about the actual structure of the organisms and their environment

Evolution  Types of Fossils petrified bones imprints molds preserved in tar, amber, or ice

Evolution  Dating of fossils Layering of fossils  Older fossils are found in the lower levels of sediment Carbon-14 Dating  Carbon-14 is a radioactive isotope in all living organisms.  It decays at a known rate  Carbon-12 does not decay  Compare ratio of C-12 to C-14 to determine age

Evolution  Contemporary changes DDT resistance in insects Antibiotic resistance in bacteria  Indirect Evidences Evidences of common ancestry Parts of the body with similar (homologous) structures

Evolution  Indirect Evidences Similar patterns of inheritance Biochemical Similarities (protein and DNA) Vestigial organs

The Methods of Change  Lamarck’s Theory – 1809 “Inner need” to change Inheritance of acquired characteristics(based on use and disuse) Disproved

The Methods of Change  Charles Darwin and Natural Selection - (1859) Naturalist on HMS Beagle Exploration of South America (3 ½ years) Visited the Galapagos Islands

The Methods of Change  Natural Selection Living things increase in number geometrically - (overproduction) There is no net increase in the number of individuals over a long period of time A “struggle for existence” exists since not all individuals can survive

The Methods of Change  Natural Selection No two individuals are exactly alike (variation) In the struggle for existence those variations which are better adapted to their environment leave behind them proportionately more offspring than those less adapted - (Survival of the Fittest)

The Methods of Change  A Modern Perspective Mutation  A sudden change in the genetic material (A source of variation) Recombination of genes within a population  Provides new combinations for natural selection  Shows how the percentage of genes in a population can change

The Methods of Change  A Modern Perspective Isolation  Separation of a population from others of the same kind Natural Selection  Certain traits give an adaptive advantage to organisms and they leave more offspring

Species  A group of individuals that LOOK similar and are capable of producing FERTILE offspring in the natural environment.

Population  All of the members of the same SPECIES that live in particular AREA at the same TIME.

Variation in a population  Bell Curve The distribution of traits (Average is the middle.)  Mode The number that occurs most often (High pt.)  Range The lowest number to the highest number

Gene Pool  The collection of GENES for all of the traits in a POPULATION

Hardy-Weinberg Principle  Genetic Equilibrium No CHANGE in the gene pool

Conditions that must exist for genetic equilibrium 1. No MUTATION 2. No MIGRATION 3. Large POPULATION 4. Random MATING 5. No NATURAL SELECTION

Natural Selection Four types of selection 1. Stabilizing Selection 2. Directional Selection 3. Disruptive Selection 4. Sexual Selection

Stabilizing Selection  Individuals with the AVERAGE form have the ADVANTAGE

Directional Selection  Individuals with one of the EXTREME forms have the ADVANTAGE

Disruptive Selection  Individuals with either of the EXTREME forms have the ADVANTAGE

Sexual Selection  Preferential choice of a MATE based on the presence of a specific trait

Speciation  The formation of new SPECIES

Isolation  Separation of a formerly successful BREEDING population

Geographic Isolation  Separated PHYSICALLY from each other

Reproductive Isolation  Can no longer produce FERTILE offspring

Extinction  When an entire SPECIES dies off.