HISTORY AND THEORY OF EVOLUTION Examine the evolutionary

HISTORY AND THEORY OF EVOLUTION Examine the evolutionary basis of modern classification systems.

Evolution Before Darwin § Aristotle – 385 -322 BC § Revered Greek philosopher & scientist § Believed organisms were created in a permanent form that could not change over time § His ideas were highly influential for centuries

Evolution Before Darwin § Jean Baptiste de La. Marck – 1800 s § French naturalist § Believed inheritance of acquired traits were the driving force of evolution. § Believed traits were acquired through use and disuse. § Ex: A giraffe had to stretch its neck in order to reach food – so the neck got longer during the giraffe’s lifetime and was passed to the next generation.

Evolution Before Darwin § Geologists were discovering ancient bones, shells, & fossilized plants in England in the 1800 s. § These items were being found in hillsides & riverbeds & gave new clues about diversity of organisms.

Evolution Other Names Who Influenced Darwin § James Hutton & Charles Lyell – Gradualism Earth had changed over very long periods of time. § Thomas Malthus – Struggle for survival Populations outgrew resources & had to compete.

Evolution Darwin’s Voyage § In 1831, Darwin set sail on the HMS Beagle § Darwin’s role on the ship was as naturalist and companion to the captain. § His job was to collect biological and geological specimens during the ship’s travel.

Evolution The Galápagos Islands § Off the west coast of South America § Each island had a unique climate & geographical features. § Darwin began to collect mockingbirds, finches, and other animals on the four islands. § He noticed that the different islands seemed to have their own, slightly different varieties of animals.

Evolution The Galapagos Islands – cont’d § Darwin theorized that the island populations came from the same ancestral populations on the mainland. § Populations from the mainland changed after reaching the Galápagos.

Evolution Concepts That Emerged from Darwin’s Work… § ADAPTATIONS – inherited traits that may give an individual survival & reproductive advantages over other individuals. § Darwin hypothesized that new species could appear gradually through small changes in ancestral species. § Darwin inferred that if humans could change species by artificial selection, then perhaps the same process could work in nature (natural selection).

Evolution Concepts That Emerged from Darwin’s Work… cont’d § REPRODUCTIVE ISOLATION – populations that geographically separated may give rise to adaptations specifically suited to each environment.

Evolution Principles of Natural Selection § Individuals in a population show variations. § Variations can be inherited. § Organisms have more offspring than can survive on available resources (overproduction). § Variations that increase reproductive success will have a greater chance of being passed on.

Evolution Darwin & Wallace § Darwin published On the Origin of Species by Means of Natural Selection in 1859. § Natural Selection was a means of explaining how evolution works. § Wallace also studied & wrote about evolution, emphasizing competition of resources, while Darwin focused on reproductive success. § Darwin’s amount of data & thorough explanations caused his theories to be become dominant.

Evolution Chapter Diagnostic Questions Which is not a principle of Darwin’s theory about the origin of species? A. Individuals show variations. B. Variations can be inherited. C. Organisms have more offspring than available resources will support. D. Offspring always inherit the best traits. 1. 2. 3. 4. A B C D

Evolution Formative Questions Which was Charles Darwin’s only qualification for his position as naturalist on the Beagle? A. a degree in theology B. an interest in science C. a knowledge of biology D. an understanding of geology 1. 2. 3. 4. A B C D

Evolution Formative Questions What was Darwin’s term for selective breeding? A. evolution B. speciation C. artificial selection D. natural selection 1. 2. 3. 4. A B C D

Evolution Formative Questions What did Darwin infer from his observations of artificial selection? A. Animal breeders could create new species. B. A similar process could work in nature. C. Reproductive success could be increased. D. Variation in a species could be produced. 1. 2. 3. 4. A B C D

Evolution Formative Questions What is the relationship between the terms natural selection and evolution? A. They mean the same thing. B. Evolution works against natural selection. C. Evolution explains how natural selection works. D. Natural selection explains how evolution works. 1. 2. 3. 4. A B C D

Evolution Standardized Test Practice Which explains why the tortoises on the different islands of the Galápagos had slightly different variations in their shells? A. The different tortoises were different species. B. The environment on each island was different. C. Each type of tortoise could survive only on its own island. D. They arrived on the islands from different continents. 1. 2. 3. 4. A B C D