8.1-Scientific Contribution to a Theory of Evolution Where did we come from?? 8.1-Scientific Contribution to a Theory of Evolution SBI3U1

So…Where did we come from? This question has been asked for 1000’s of years Early ideas based on religion and philosophy suggest that living things exist unchanged 1600’s empirical studies began in Europe Observation and experiment to form hypotheses about nature

John Ray (1627-1705) One of the 1st scientist to carry out empirical studies on nature Developed classification system for plants and animal, based on anatomy and physiology Later extended by Carolus Linnaeus

Georges-Louis Leclerc (1707 – 1788) He challenged the idea that life forms are unchanging He noted the similarities between humans and apes He speculated that Earth was more than 6000 years

Mary Anning (1799-1847) worked as a fossil hunter and uncovered the first plesiosaur Her work was confirmed by Georges Cuvier, the founder of “paleontology” (the study of acient life through fossils)

Georges Cuvier ( 1769-1832) Founder of the field of paleontology (study of fossils) discovered that each stratum (layer) of rock held a unique group of fossil species discovered that the oldest fossils are in the deepest layer suggested that catastrophes killed many species (catastrophism) and that these events corresponded to the boundaries between the fossil strata  

Charles Lyell (1797-1875) He rejected Cuvier’s theory of catastrophism agreed that Earth was more than 6000 years old He proposed the theory of uniformitarianism: geological processes in the past operate at the same rate as they do today suggested that a slow and continuous process could result in substantial changes in the long term

Jean-Baptiste Lamarck (1744-1829) proposed a “line of descent” progression between current species and fossil forms suggested species increased in complexity and became better adapted to their environment over time proposed the idea of the inheritance of acquired characteristics whereby characteristics acquired during an organism’s lifetime could be passed on to offspring

Charles Darwin (1809-1882) travelled the coast of South America and made natural & geographical observations used these observations to propose the “theory of natural selection” -life has changed and continues to change, due to natural pressures

Darwin’s Journey with the HMS Beagle (a british survey ship)

Darwin’s Observations 1. Flora and fauna of the different regions were distinct from those in Europe. Example: rodents in South America were structurally similar to one another, but different from other continents

Darwin’s Observations Cont’d 2. Fossils of extinct animals looked very similar to living animals Example: extinct glyptodont and modern armadillo from South America glyptodont armidillo

Darwin’s Observations Cont’d 3. Finches and other animals Darwin saw on the Galapagos Islands closely resembled animals he had observed on the west coast of South America

Darwin’s Observations Cont’d 4. Galapagos species (tortoises and finches) looked identical at firsrt, but … Varied slightly between islands Each finch was adapted to eating different type of food Different beak size and shape

Darwin’s Observations Cont’d 5. Through his experience with artificial selection (breeding pigeons and studying dogs and flowers) , he knew it was possible for traits to be passed down from parent to offspring

Theory of Evolution by Natural Selection… Survival of the Fittest: organisms that are the “fittest” leave the most offspring, so those organisms win the struggle for survival. Their genetic traits are then passed on to future generations Darwin called this “natural selection”

Darwin’s Theory of Natural Selection As written in his book of The Origin of Species 4 ideas summarized 1)Organisms produce more offspring than can survive (leads to competition for resources) 2)Individuals of a population vary extensively (it is inheritable) 3)Individuals better suited to local condition survive to reproduce 4)Processes for change are slow and gradual

HOMEWORK Make a chart summarizing all the ancient Scientist s theories and their contribution to evolution. Use this as a study tool for upcoming quizzes and tests. Read 8.1 ( pg. 326-330) Complete pg. 331 Q #1, 4, 5, 7, 12