INTRODUCTION TO EVOLUTION UNIT #5 EVOLUTION

Evolution Change in genetic composition over time “Descent with Modification”

Darwin’s Influences Aristotle (384 – 322 BCE) Viewed species as fixed (unchanging) Believed that life-forms can be arranged on a ladder Scala Naturae (Scale of Nature) His ideas were consistent with the Old Testament Species were designed by God (therefore perfect) Species were created by God for a particular purpose

Darwin’s Influences Carolus Linnaeus (1707 – 1778) Worked “for the greater glory of God” Developed the two-part (binomial) format for naming species Homo sapiens – Humans Adopted a classification system grouping similar species into increasingly general categories Same Family Same Genus

Fossils Darwin also gained many ideas from scientists that studied fossils Fossils – remains or traces of organisms from the past Found in sedimentary rocks from the sand and mud New layers of sediment cover older ones compressing them into super-imposed layers of rock called strata As time passes, erosion carves through upper (younger) strata revealing deeper (older) strata that had been buried Paleontology – the study of fossils

Darwin’s Influences Georges Cuvier (1769 – 1832) Noticed the older the stratum (layer), the more dissimilar its fossils were to current life-forms. Observed that from one layer to another, some new species appeared while others had disappeared. Inferred in the idea of extinction, while opposing to the idea of evolution He believed that each boundary between strata represented a catastrophic event

Darwin’s Influences James Hutton (1726 – 1797) Hutton proposed that Earth’s geographical features can be explained by slow and gradual mechanisms Charles Lyell (1797 – 1875) incorporated Hutton’s thinking into his proposal He believed the same geologic processes are occurring today as in the past, and at the same rate Hutton and Lyell’s ideas influenced Darwin into thinking that geologic change occurs through slow, continuous actions rather than sudden events Led Darwin to believe that Earth is more than thousands of years old .

Darwin’s Influences Jean Baptiste de Lamarck (1744 – 1829) Proposed a mechanism for how life changes over time He is not remembered for his recognition that evolutionary change explains patterns in fossils and the match of organisms to their environments Remembered for the incorrect mechanisms that he proposed Found what appeared to be several lines of descent Each in a chronological series of older - younger fossils - present- day species

Darwin’s Influences Jean Baptiste de Lamarck (1744 – 1829) He explained his findings with two principles that were widely used at the time Use and Disuse - belief that parts of the body that are mostly used become stronger and larger, while those that are not used start to deteriorate Inheritance of Acquired Characteristic - an organism can pass these modifications to its offspring He believed that evolution occurred due to an organisms desire to become more complex (rejected by both Darwin and Cuvier)