Chapter 8: Developing a Theory of Evolution 8.1 Scientific Contributions to a Theory of Evolution

Agenda Review yesterday’s homework Chapter 8 Launch Activity Lesson 8.1 Scientific Contribution to a Theory of Evolution Read pages Learning Check page 327 # 3 Workbook SG #2, #4

Learning Goals Students will define the following terms: paleontology, catastrophism, uniformitarianism, inheritance of acquired characteristics, theory of evolution by natural selection, evolution, survival of the fittest, descent with modification. Students will look at the scientific contributions of Georges-Louis Leclerc, Mary Anning, Georges Cuvier, Charles Lyell, Jean-Baptiste Lamarck and Charles Darwin and Alfred Wallace. Students will summarize Darwin’s 5 observations. Students will summarize Darwin’s ideas on natural selection.

Launch Activity Forming A Hypothesis Many theories are developed and modified as a result of collaborating with others. In this activity you will collaborate a partner try to identify an animal from its paper fossil bones. Materials: Paper fossils Printout of fossil remains of various animals Procedure 1.Open your envelope and remove 3 fossil bones. Do not look at the others in the envelope. Try arranging the bones in different ways to help you form a hypothesis about the identity of the animal. Record the hypothesis in the table provided. 2. Remove 3 more bones. Revive you hypothesis if necessary and record your new hypothesis. 3 Remove 4 more bones, if necessary revise your hypothesis. 4. Compare your findings with another group. Revise again if necessary 5. Compare your fossil assembly with the printout of fossil remains of other animals. Note any similarities or differences. 6. Return your bones to the envelope and the teacher.

Class Discussion 1.Did you and your partner reach an agreement on the identity of the animal? Explain why or why not. 2.From looking at the printout and the fossil what could you say bout how and where this animal lived. 3.What features of the nature of science do you think this activity demonstrates?

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

Scientific Contributions to the Theory of Evolution Georges-Louis Leclerc, Comte de Buffon ( ) French naturalist challenged the idea that life forms are unchanging wrote a 44 volume set called Histoire Naturelle noted similarities between humans and apes and suggested a common ancestor. suggested that species changed over time he speculated that Earth was more than 6000 years

The Science of Paleontology Fossils- the preserved remains of a once-living organism Preserved in amber, permafrost, dry caves, as rock Mary Anning ( ) worked as a fossil hunter and uncovered the first plesiosaur Her work was confirmed by Georges Cuvier, the founder of “paleontology” (the study of ancient life through fossils)

Georges Cuvier ( ) 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 ( ) 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 i.e. floods in the past had no greater power than floods that occur today. suggested that a slow and continuous process could result in substantial changes in the long term

Jean-Baptiste Lamarck ( ) proposed a “line of descent” - a progression in which a series of fossils, from older to more recent, led to a modern species suggested species 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 ( ) Darwin left England on the HMS Beagle, a British survey ship to map the coast of South America. The 5 year journey took him about most of the world. He made observations about the natural history of different geological locations. He 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

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 those from other continents

2. Fossils of extinct animals looked very similar to living animals Example: extinct glyptodont and modern armadillo from South America

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

4. Galapagos species (tortoises and finches) looked identical at first, but they varied slightly between islands Each finch was adapted to eating a different type of food based on the size and shape of their beak.

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

Darwin, Wallace and the Theory of Evolution by Natural Selection Individuals with traits that helped them survive in their local environments were more likely to survive to pass on these traits to their offspring. Survival of the Fittest: organisms that are the “fittest” leave the most offspring, so these 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 In 1859, he published a book called The Origin of Species Ideas on Natural Selection 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

Darwin did not use the term “evolution” in his book but instead spoke of descent with modification He felt the word evolution suggesting that each generation was improved. He felt that natural selection did not demonstrate progress.