Full Name: ______________________ Date: ____________ Period: ____ Unit B: Evolution & DNA Checkpoint: ch#15 – Darwin’s Theory of Evolution Instructions: please answer the questions in full sentences. 1) Explain what is meant by the term evolution, and give an example. Evolution, or change over time, is the process by which modern organisms have descended from ancient organisms. An example is a population of predators in which the fastest animals passed on their traits (all the traits, as well as being fast) to new generations. 2) Describe where the Galapagos Islands are located. How did the visit to the Galapagos Islands affect Darwin’s thoughts on evolution? Please describe the living organisms, that Darwin observed on the Galapagos Islands, that helped support his thoughts on evolution. The Galapagos Islands are located many kilometres off the northwest coast of South America. Darwin’s visit to the Galapagos Islands convinced him that new species might arise from existing species over time. Each Galapagos Island had very different habitats. Darwin observed that different tortoises and different birds (finches in particular) lived on each Galapagos Island. 3) How did Hutton’s and Lyell’s Views of Earth differ from that of most people in their time? Hutton proposed that Earth had to be millions – not thousands – of years old. Lyell argued that the same forces (such as plate tectonics, movement of the continental plates) change Earth in the present as in the past, so scientists should explain Earth’s history in terms of processes that are observable in the present. 4) a) Explain Lamarck’s principle of use and disuse. b) Use an example to explain Lamarck’s proposal that acquired traits are passed onto their offspring. (acquired trait: a trait that an organism develops in its lifetime; c) Why were Lamarck’s hypotheses of evolution incorrect? a) Lamarck said that structures that are used to develop and are passed on to offspring (new generations), whereas structures that are not used are not passed on. b) Lamark believed that acquired traits could be passed onto offspring. Some examples are: - if a giraffe stretches its neck enough to reach food during its lifetime, its neck will get longer. Lamark believed the giraffe will pass on this long neck trait to its offspring. - if a human builds up very large muscles, from weight lifting, it will pass on these large muscles to its offspring - if a crab uses one claw many times, then it will increase the size of the claw. That crab’s offspring will be born with large claws c) Lamarck’s hypotheses of evolution were incorrect because a single organism’s behaviour has no effect on its heritable characteristics (traits that can be passed on through sexual reproduction). 5) Distinguish between fitness and adaptation. Give an example of each. Fitness, the ability of an individual to survive and reproduce in its specific environment, occurs through ongoing adaptation. An example is an animal that survives through camouflage. An adaptation is any inherited characteristics that increases an organism’s chance of survival. Examples include a porcupine’s quills, a lions teeth and claws.