BSC 2011 UNIT III STUDY GUIDE: PART A UNIT III: Evolution and Population Genetics1. Discuss the following various views people held about life’s diversity (how it arose) and the age of the earth (old? young?) before evolution was suggested: (a) essentialism/idealism Plato is an "Essentialist"- God created all things- All things have a constant, perfect essence "ideal form"- Variation is and imperfect reflection of the inner essence- No potential life was left unrealized- species don't change; no new species Aristotle and the "Scala of Nature" (Scale of Nature)- All living things are fixed in a linear hierarchy- Nothing was left out of the hierarchy - a.k.a species can't, won't and shouldn't change(b) natural theologyNatural Theologians (monotheistic Western Christians educated around 1600s - 1700s- Studied the natural world to better understand God's Plan- All species were divinely created perfectly all at the same time- Around 6000 years ago based on Judeo-Christian book of Genesis from the Old Testament - Islam and Hindu religions also have similar creation story- Side Note: As early as 4th century Saint Augustine wrote God probably only created simple life forms and these developed over timeCarolus Linnaeus (~1750)- Organized Life in a nested classification system based on similar appearance - Each type of organism had a 2-part binomial scientific name (Genus & Species)- Either Italicized or Underlined Charles Darwin (1809-1882)- Attended Cambridge to become a minister and a naturalist- 1831: unpaid naturalist on 5 year voyage on the HMS Beagle- 1. He observed that organisms on same continent more similar than ones on different continents2. He saw a correlation between location and similarity and this suggested common ancestry. - Extended Malthus ideas to plants and animals- Populations in nature are capable of far greater growth than natural resources can support- Survival of the fittest Thomas Malthus (1766 – 1834)- Demographer and political economist- He said the fate is the poor is inescapable because their reproduction exceeds their means of sustenance (e.g. higher infant mortality and childhood mortality)- This was the first suggestion of resource limitation & competition leading to “survival of the fittest” Alfred Wallace 1858- Sends Darwin an example of his manuscript outlining his idea of evolution by natural selection, which forces his hand in publishing his manuscript, On the Origin of Species (c) catastrophismGeorges Cuvier (1769 - 1832)- One of the early Paleontologists also a natural theologian- Accepted divine creation - Believed in a relatively young age for Earth- Sporadic catastrophes caused the appearance and disappearance of organisms the fossil record- E.g. Local floods wiped out existing species and neighboring species moved in - a.k.a No Evolution(d) uniformitarianismJames Hutton (1726-1797)- Geological gradualism- Geological features were formed slowly and gradually over a long period of time, not by catastrophes. (e.g. erosion and sedimentation) Charles Lyell (1797 - 18- Mechanisms of geological change are constant over time- The same processes that happen today happened in the past, at the same rate- Therefore: The earth must be very old to accumulate all of the geological changes that have occurred. Jean Baptiste Lamarck (1744 - 1829)- Species evolve by gradually changing to adapting to their environment - Evolutionary relationships among animals - Right idea wrong mechanism - "Use and disuse" - if you use it it becomes stronger, if you don't use it then you lose it over time- "Inheritance of acquired characteristics" - the traits that are acquired through lifetime by responding to the environment can be inherited. 2. (a) What is the biological meaning of the term “evolution”? Species change over time and new species arises by the modification of earlier species(b) Contrast microevolution with macroevolution.Microevolution: The gradual evolution of traits within a population of a species over time; populations evolve not individuals.Macroevolution: The evolution of an entirely new species 3. Describe/explain how each of the following served as evidence at the time of Darwin that evolution could be a means by which life’s diversity arose: (a) artificial selection(b) comparative anatomy(c) geology(d) paleontology(e) comparative embryology?4. (a) How can molecular biology provide evidence for evolution? (b) Provide two examples. 5. Distinguish between (a) homologous, (b) analogous, and (c) vestigial structures, providing at least ONE EXAMPLE of each.6. (a) What did Darwin find intriguing about the finches on the Galapagos Islands? There were 14 endemic species of finches (found nowhere else) (b) Explain why/how the Galapagos finches might have helped Darwin formulate his hypothesis of evolution by natural selection.They evolved from a common mainland ancestor, each adapted to different lifestyles & conditions on the various islands. 7. (a) Describe the process by which populations evolve via natural selection. 1. Within a population more offspring are produced that can survive. Therefore there is a competition for resources struggle for existence.2. Random variation exists in all organisms and most is heritable (genetic)3. Some of this variation affects fitness, therefore the ability to survive and reproduce is random4. More fit individuals produce more offspring and pass along more of their genes to the next generation.5. This results in a change in gene composition from one generation to the next with adaptive characteristics accumulating over time. This change in a gene composition in a population over time is evolution. (b)Why is it said that genetic variation is a prerequisite (is required) for evolution by natural selection?There is differences in survival and reproduction among individuals favoring the advantageous rates. 8. Lamarck thought that evolution was the best explanation for life’s diversity, as did Darwin. How did Darwin’s view differ from Lamarck’s?Lamarck had the right idea about evolution but he had the wrong mechanism, which Darwin had. Lamarck had two ideals about the mechanism of evolution: that if you use a body part it becomes stronger, if you don’t then over time it disappears; traits that an individual acquires in his lifetime by adapting to their environment can be passed along to their offspring. Darwin's explanation is based on natural selection, "survival of the fittest", based on Malthus
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