Change over Time Evolution Evolution defined change in

Change over Time

Evolution • Evolution defined: change in inherited characteristics of a species over time – Inherited means • Traits passed to offspring from parent(s) – Species means: • Group of organisms with similar characteristics that can reproduce to form fertile offspring

Some Ideas about Evolution: Lamarck • Jean-Baptiste de Lamarck (1744 -1829) • Soldier, interested in natural science • Major contributor to the Cell Theory – All living things have cells – Cells are the basic unit of organization and structure in living things – All cells come from other cells

Jean-Baptiste de Lamarck • Two main ideas in his idea about evolution – Environment causes changes in organisms – Life is orderly and structured • Method of change was called “use and disuse” or acquired characteristics

August Weismann • Born 1834, died 1914 • Believed gametes were the mechanisms for change in organisms • Mutation in gametes is passed to offspring and may cause change • Tested acquired characteristics in experiment with mice

Charles Darwin • Born 1809, died 1882 • Travelled with HMS Beagle to South America and Pacific Islands in 1831 – 5 year journey – Distribution of organisms and fossils varies geographically • Idea of natural selection based on his collections

Galapagos Islands

Galapagos Islands • Darwin noticed organisms looked different on different islands • 11 species of Galapagos tortoise • Galapagos marine iguana and Galapagos land iguana • 13 different species of finch

Galapagos Tortoise

Galapagos Iguanas

Darwin’s Finches

Natural Selection • Proposed by Darwin as method of evolution • Organisms have a range of characteristics • Organisms with favorable phenotype are more likely to survive and reproduce – Phenotype means: • What an organism looks or acts like due to its genotype • Darwin did not know about genes • Enough change over time led to new species • Published “On the Origin of Species” in 1859

Your Assignment! • Read pages 154 -156 in your book. • If you see any new ideas that you did not record today, record them in your notes!