Study Guide Midterm 2 Darwin and Evolution 1 What did Darwin do What was the name of the ship he took his voyage on What was his role on that voyage The name of the ship was HMS Beagle Darwin was the sip s naturalist Darwin read all of Charles Lyell s books on the Principles of Geology Uniformitarianism and he recorded his observations as the ship journeyed around the coast of South America He noticed the differences between organisms When in Galapagos Island he found notes and samples that would be the seed of his theory of evolution 2 Who wrote the book on geology that gave him the idea of slow change of geological features on earth 3 Who gave Darwin the idea that populations tend to overproduce Charles Lyell Malthus 4 What did Darwin mean by Descent with Modification Descent implies inheritance modification refers to changes in heritable traits from generation to generation Gradual changes from an ancestral type 5 What is artificial selection Artificial selection also called selective breeding is when a human chooses one or a few desired traits such as milk production or seed size and then allows only the individuals that best express those qualities to reproduce Who uses it Farmers horticulturists etc Example Breeds of domesticated dogs and cats varieties of plants farmers use wild mustard seed to breed broccoli cauliflower kale cabbage etc 6 What is natural selection Natural selection occurs when environmental factors cause the differential reproductive success of individuals with particular genotypes Darwin used to describe it as the preservation of favorable variations and the rejection of injurious variations Species adapt and reproduce The ones that are not able to adapt to environmental conditions go extinct Natural selection changes the genetic makeup of a population Alfred Russell Wallace provided evidence for natural selection as well Examples 7 What is evolution A genetic change in a population over multiple generations Occurs in a population when some alleles become more common and other less common from one generation to the next changes in allele frequency 8 Describe how the following explain evolution Darwin the most favorable traits would continue to pass from generation to generation and non favorable traits would disappear from the population through natural selection Wallace organisms evolve slowly and uniformly through generations Lamark organisms that used one part of their body repeatedly would increase their abilities Conversely disuse would weaken an organ until it disappeared He surmised incorrectly that these changes would pass to future generations 10 List and describe Darwin s main ideas about evolution by natural selection a Organisms are varied and some variations are inherited Within a species no two individuals except identical siblings are exactly alike b More individuals are born than survive to reproduce c Individuals compete with one another for the limited resources that enable them to survive d Within populations the inherited characteristics of some individuals make them more likely to survive and produce fertile offspring e Because of the environment s selection against non adaptive traits only individuals with adaptive traits live long enough to transmit their genes to the next generation Over time natural selection can change the characteristics of populations even giving rise to new species 11 What is convergent evolution Give examples Convergent evolution is when two species that live on opposite sides of the planet may nevertheless share characteristics because they evolved in similar environmental conditions It produces similar adaptations in organisms that do not share the same evolutionary lineage Structures are analogous they evolved independently Ex Birds and insects the wings have the same function flight but birds wings evolve from the modification of limb bones and insects wings come from outgrowth of the exoskeleton Ex Dolphin is a mammal and shark is a fish 12 How would each of the following describe how the giraffe got its long neck Darwin would say that there were a variety of giraffes with short and long necks but the struggle to resist would cause the giraffes with longer necks to have more offspring and due to natural selection the giraffes with that trait reproduced Wallace giraffes slowly grew their necks through generations Lamarck would say that giraffes got their long necks from stretching and then future generations where born with long necks 13 Describe each of the following ideas that were used to explain evolution catastrophism uniformitarianism Ideas from GEOLOGY a uniformitarianism theory proposed by James Hutton which suggested that the processes or erosion and sedimentation that act in modern times have also occurred in the past producing profound changes in Earth over time b catastrophism theory proposed by Georges Cuvier which suggested that a series of brief violent global upheavals such as enormous floods volcanic eruptions and earthquakes were responsible for most geological formations By Georges also Principle of superposition lower layers of rock and the fossils they contain are older than those above them Malthus Principles of Population food availability disease and war limit the size of a human population All individuals in a population are different and the ones better able to obtain resources were more likely to survive The fittest survive Over time environmental challenges would eliminate the more poorly equipped variants and gradually the population would change lack of food Lamarck inheritance of acquired characteristics Not accepted by modern genetics Modern evolutionary synthesis suggests that genetic mutations create heritable variation and this this variation is the raw material upon which natural selection acts Mutations changes in DNA sequence Microevolution Relatively short term genetic changes within a population or species occurs on a much smaller scale 1 What is genetics Why is it important in the understanding of evolution Genetics is inherited characteristics It is important in the understanding of evolution because evolution is change in appearance not in genetic makeup so the phenotype is what changes 2 What is a gene An allele A gene is a portion of DNA whose sequence of nucleotides encodes a protein An allele is an alternate form of a gene created by mutations of a gene 3 What does a gene code for A gene encodes a protein chromosomes 5 Define 4 What is a gamete How many