EVOLUTION – change in populations over time HISTORY – ideas that shaped the current theory  James Hutton (1785) – proposes that Earth is shaped by geological forces that took place over extremely long periods of time --- estimates earth to be millions of years old. Scientist now believe Earth is 4.6 billion years old!

 Jean-Baptiste Lamarck (1809) – Proposed that organisms changed over time by the inheritance of acquired traits. Lamarck thought that you would gain or lose features if you used or didn't use them, and you could pass these new traits onto your offspring. PROVEN TO BE WRONG!

 Charles Lyell (1833) – processes occurring now have shaped Earth’s geological features over long periods of time.  Charles Darwin (1859) – Publishes “The Origin of Species” explaining his theory of evolution by NATURAL SELECTION. From 1831 to 1836 Darwin served as naturalist aboard the H.M.S. Beagle on a British science expedition. In South America Darwin found fossils of extinct animals that were similar to modern species. On the Galapagos Islands, he noticed variations among plants/animals of the same type in South America.

 Natural Selection is the process by which individuals with beneficial traits survive and reproduce more successfully than other individuals, causing those beneficial traits and the genes that code for them to accumulate in later generations

Mutations cause variation in traits More offspring are produced than can survive Only individuals with beneficial traits are able to survive & reproduce Over many generations, the beneficial trait will accumulate, causing the population to be better adapted to the environment

 Acts directly on an organisms phenotype and indirectly on its genotype  “Survival of the Fittest”  Fit: Well adapted; reproductively successful (good at passing on its genes to the next generation)  Not necessarily the biggest or strongest! Examples of Natural Selection Example 1: Antibiotic resistant bacteria Example 2: Pesticide resistant insects Example 3: Bill length in Hummingbirds in response to flower shape

 Over long periods of time, Natural Selection causes populations of organisms to be better suited to their environment  The characteristics of an organism that help it survive and reproduce in its environment are called adaptations. Example 1: White fur camoflauges polar bears Example 2: Harmless snakes mimic the patterns of venomous snakes Example 3: Spots on moth wings resemble eyes of a larger animal

 FOSSIL RECORD ◦ Fossil: The preserved remains of an organism ◦ Fossils are a record of life’s history. ◦ By comparing fossils from older rock layers with fossils from younger layers, scientists have learned that life on Earth has changed over time EVIDENCE of evolution

SIMILARITIES IN EARLY DEVELOPMENT E = hog F = calf G = rabbit H = human All vertebrates go through similar stages of embryonic development. The same embryonic tissues develop into the same adult structures

Comparison of Human Hemoglobin to other species SpeciesAmino acid differences Gorilla1 Rhesus Monkey8 Mouse27 Chicken45 Frog67 Lamprey125 All life is based on DNA All organisms use the same genetic code More closely related species will have more similar DNA and amino acid sequences

 study of body forms and structures in an organism --- This can reveal similarities that suggest inheritance from a common ancestor. HOMOLOGOUS STRUCTURES – structures have different mature forms, but have the same underlying anatomy Organisms have descended from a common ancestor.

ANALOGOUS STRUCTURES – structures have similar function and appearance, but different anatomy  Similarities are due to environmental pressures, but do not demonstrate common ancestry. Appear due to convergent evolution

VESTIGIAL ORGANS – organs that are reduced in size and have no function. Structures have no current function, but can provide information about ancestors.

 Microevolution: The small changes in a population from one generation to the next.  Macroevolution: The large-scale changes that occur in a group of organisms over very long time periods (i.e. the evolution of birds from dinosaur ancestors). Because of macroevolution, Earth’s biodiversity has increased over time!

 Patterns of Macroevolution ◦ Speciation – New species evolve when different populations of an existing species become isolated, diverge (split), and evolve independently for millions of years.

Adaptive Radiation: Many new species evolve in a relatively short time period when an ancestral population adapts to new environments. Adaptive radiation of Darwin’s finches in the Galapagos Islands is one example of this process.

 Convergent evolution : the appearance of structures that have similar appearances and functions in distantly related species. many organisms on different continents look alike and share many similarities, but are unrelated The similarities evolved due to exposure to similar environmental pressures.

 CoEvolution is the joint change of two or more species that interact closely. ◦ Example - Pollinators & the flowers they pollinate have coevolved so that both have become dependent on each other for survival.

 Mass Extinction – Sometimes many species go extinct (disappear) in a relatively short period of time. There have been 5 mass extinctions in earth’s history. The most recent took place 65 million years ago and resulted in the extinction of the dinosaurs.

 Endosymbiosis: The hypothesis that an ancestral eukaryotic cell engulfed other cells, which became organelles (mitochondria, chloroplast).

Gradualism – organisms descend from a common ancestor slowly over a long period of time. Punctuated Equilibrium – new species appear suddenly after long periods of little change RATES OF EVOLUTION

 CLADOGRAMS/PHYLOGENETIC TREES Phylogeny: The evolutionary history of a group of an organism or group of organism Phylogenetic tree/cladogram: Like a family tree. Shows the evolutionary relationships between species or groups of species. Branching points represent the common ancestor of two groups. More closely related species have common ancestors higher up on the tree than distantly related species.