General Biology: Evolution
General Biology: Evolution BIO 1050 - 02
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This 3 page Study Guide was uploaded by Kara Fields on Thursday April 7, 2016. The Study Guide belongs to BIO 1050 - 02 at East Carolina University taught by Dr. Whelan in Spring 2016. Since its upload, it has received 11 views. For similar materials see General Biology in Biology at East Carolina University.
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Date Created: 04/07/16
Biology 1050 Spring 2016 Dr. Whelan Evolution I. Evolution has 2 meanings to biologists: a __Process____ and a ___Theory__________ . A. What do biologists mean by the process of evolution? Change in the frequency of alleles in a population over many generations. a. What is a population? A population is a group of individuals of the same species living in the same geographical region. b. Can individuals evolve? No c. Can populations evolve? Over time d. Example: selection of antibiotic resistant bacteria; nonresistant bacteria are killed and resistant ones are able to survive and thrive. B. Observations of the Process of Evolution a. What are some examples of the process of evolution that people have been able to witness? Drug resistant, pesticide resistant insects, herbicide resistant plants b. Explain how fruit flies have changed from starving after 20 hours (on average) without food to being able to survive for more than 160 hours (on average) without food. Food is removed until 80% of the population is dead; this process is repeated for 60 generations. Each generation the remaining 20% gives rises to the next generation. C. What is the theory of evolution? All species are descendants of a single common ancestor, and all species are the result of millions of years of change. D. Charles Darwin a. Describe the background of Charles Darwin, including his travels. See textbook b. Describe what Darwin’s observations of finches helped him realize. The finches on each of the Galapagos Islands resembled one another and the mainland finch of Ecuador, but were still individual species. c. Describe what Darwin’s observations of fossils helped him realize. Fossils of extinct species found in an area resembled living organisms in the same area. d. Darwin finally published his ideas about evolution in a book. What was this book called and when was it published? On the origin of species by means of natural selection or preservation of favoured races in the struggle for life, 1859 e. What were the two main points of this book? It provided evidence of evolution and proposed the mechanism of natural selection. 1 Biology 1050 Spring 2016 Dr. Whelan f. What was the worldview before Darwin published his ideas? A creator placed all organisms the planet at the same time, species were not added or subtracted, and the earth was 6,000 years old and mostly unchanging. g. What was the worldview after Darwin published his ideas? Organisms change over time and some have gone extinct. The earth is greater than 6,000 years old and is always changing. II. Evidence of Evolution – There are many types of evidence for evolution. A. The fossil record a. What are fossils? Preserved remains or impression of organisms that lived in the past. b. Do all species leave fossil remains behind? No c. What are two ways you can tell the age of fossils? 1) Geologists study rock layers and fossils in them to determine relative age, and 2) radiometric dating. i) What fossils are oldest? Bacteria ii) How old are they? 3.5 billion years iii) What organisms appear in the fossil record most recently? Animals d. What have paleontologists discovered? There are transitional versions of organisms that demonstrate a evolutionary tree and link to the past. B. Biogeography a. What is biogeography? Study of the geographical distribution of species. b. Are species more similar to other species in the same area (even in different habitats) or more similar to other species in similar habitats in other parts of the world? More similar to other species in the same area. i) What does this pattern suggest? A common ancestor. ii) Describe the example of Hawaiian honeycreepers. Similar to Darwin’s finches, the birds resemble the mainland finch. iii) Describe the example of Australian marsupials. Organisms with pouches for carrying there young are found with few exceptions overwhelmingly in Australia. C. Homologies a. Define homology. Similarity in structure due to common ancestry b. Where have homologies been found? Anatomical structures, embryos, and molecules c. How can molecular biology be used to show homologies? Comparison of DNA and protein molecules can show relationship between organisms. 2 Biology 1050 Spring 2016 Dr. Whelan i) Describe the DNA nucleotide similarities between close relatives and distant relatives. Close relatives will share greater similarity in nucleotide sequences vs. distant relatives. ii) Describe how proteins (amino acid chains) differ among species. Similar to nucleotide sequences, the longer two species have evolved on there own the greater the differences in amino acid sequences of proteins. d. Define comparative embryology. The comparison of structures that appear during the early development of organisms in the embryo. i) Explain the similarities between all vertebrate embryos. Vertebrate embryos have pharyngeal (gill) slits and a tail. e. Define comparative anatomy. Comparison of body structures between species. i) Explain how the forelimbs of vertebrates show homologies. Vertebrates have versions of the same bones in the forelimbs, i.e. humerus (upper arm), ulna ann radius (lower arm), carpals (wrist), metacarpals and phalanges (hand). ii) How do homologies explain vestigial traits? Organisms with common ancestors may have traits that are no longer required for their survival, however, there is no selective pressure against those traits, and so they remain. For example, humans have a tailbone (coccyx) but no tail. iii) Does the presence of similar traits between two species always indicate that those species are closely related? No iv) Explain convergent evolution, including 2 examples from nature. Convergent evolution occurs when distantly related species evolving under similar selective pressures evolve similar traits e.g. wings of bats and insects, similarity in shape of sharks (cartilaginous fish) and dolphins (mammals). 3
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