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exam 3 questions

exam 3 questions - Exam 3 Study Questions 1 The"pattern...

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Exam 3 Study Questions 1. The “pattern component” of Darwin and Wallace’s theory is “descent with modification,” in other words, species existing today have descended from other preexisting species and that species are modified or change through time. The “process” component is natural selection. Before Darwin and Wallace the leading explanation for the diversity of organisms was a theory called special creation, which stated that God created all species independently, perhaps as recently as 6000 years ago. The process component of special creation was that all species are immutable and have been unchanged since the moment of their creation; the pattern was that there are different species. 2. Evidence that species have changed through time includes fossils, transitional forms, and extinction. The law of succession is an observed pattern in which fossils found below the surface of a certain region resemble species that currently live in the same region. This relates to transitional forms in the fossil record because they have traits that are intermediate between extinct and present species. 3. Darwin interpreted the fact that species had gone extinct as proof that species can change, disproving the theory of special creation. Vestigial traits support the view that species have changed through time because they are traits that are still passed on but are reduced or completely devoid of function. They resemble functional traits that are observed in other species. 4. One example that supports the proposition that today’s populations can and do change in response to their environment is in the study of Galapagos Finches. After a drought, the mean beak depth in the finches increases. This shows that finches with deep beaks survive better in drought conditions; the population is evolving in response to the environment. 5. The different types of homologies found to exist between organisms consist of structural, developmental, and genetic homologies. These similarities suggest that certain species are related to each other because the structural, developmental, and genetic traits of different species all seem to have originated from a common ancestor. Darwin knew structural homologies because they had been routinely documented well before Darwin. One example of a developmental homology is the fact that all vertebrates have a strong general resemblance among the embryos. Genetic homologies are similarities in DNA sequences in genes from different species. Genetic homologies were not known to Darwin. 6. All cells have a cell membrane, ribosomes, DNA/RNA, cytoplasm, and use ATP for energy. 7. The four main components of the process of natural selection are that individuals in a population vary in their traits, some of these variations are heritable, some individuals survive and reproduce better than others, and that differential survival and reproduction are influenced by the heritable traits of individuals. In the
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