Term
| Explain the mechanism for evolutionary change proposed by Charles Darwin in On the Origin of Species. |
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Definition
| The mechanism for evolutionary change proposed by Charles Darwin was "descent with modification." Darwin perceived unity in life, with all organisms related through descent from some unknown ancestor in the remote past. As the descendants of that ancestral organism spilled into various habitats, they accumulated diverse modifications and adaptions. |
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Term
| Define evolution and adaptation. |
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Definition
Evolution -> All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today.
Adaption -> An adaption is a change in an organism that makes it better suited to its environment. |
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Term
| Describe the theories of catastrophism, gradualism and uniformitarianism. |
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Definition
Catastrophism -> The hypothesis by Georges Cuvier that each boundary between strata corresponded in time to a catastrophe that had destroyed many of the species living there.
Gradualism -> A view of Earth's history that attributes profound change to the cumulative product of slow, but continuous processes.
Uniformitarianism -> Charles Lyell's idea that geographic processes have not changes throughout history. |
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Term
| Explain the mechanism for evolutionary theory proposed by Jean-Baptiste de Lamarck. Explain why modern biology has rejected Lamarck's theories. |
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Definition
| Lamarck's theory was based on the ideas of use and disuse and the inheritance of acquired characteristics. For example, Lamarck theorized that the long neck of a giraffe evolved gradually as the cumulative product of many generations of stretching higher and higher. |
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Term
| Describe how Darwin's observations on the voyage of the HMS Beagle led him to formulate and support his theory of evolution. |
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Definition
| On the HMS Beagle, Darwin observed that different tupes of animals had modifications that made them better suited to their environments. These observations led him to believe that all the animals had come from a common ancestor. |
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Term
| Explain how the principle of gradualism and Charles Lyell's theory of uniformitarianism influenced Darwin's ideas about evolution. |
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Definition
| The principles of gradualism and uniformitarianism influenced Darwin's ideas because it geological change results from slow continuous processes, then the Earth must be far older than the 6000 years based on biblical inference. Second, if small changes accumulate to substantial change, then the same principal can apply to animals. |
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Term
| Explain what Darwin meant by "descent with modification." |
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Definition
| By "descent with modification," Darwin meant that there is unity in life, with all organisms related though descent from some unknown ancestor. As the descendants of that ancestral organism spilled into various habitats, over millions of years, they accumulated diverse modifications. |
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Term
| Explain what evidence convinced Darwin that species change over time. |
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Definition
| Darwin was convinced that species changed over time after seeing population of finches on the Galapagos Islands. |
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Term
| Describe the inferences Darwin made from his observations that led him to propose natural selection as a mechanism for evolutionary change. |
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Definition
Observation 1 -> Members of a population often vary greatly in their traits.
Observation 2 -> Traits are inherited from parents to offspring.
Observation 3 -> All species are capable of producing more offspring than their environments can support.
Inference 1 -> Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment leave more offspring than other individuals.
Inference 2 -> This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in a population over time. |
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Term
| Explain how an essay by Reverend Thomas Malthus influenced Charles Darwin. |
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Definition
| Explain how an essay by Reverend Thomas Malthus influenced Charles Darwin. |
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Term
| Distinguish between artificial selection and natural selection |
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Definition
Artificial Selection -> Modification of a species by human intervention so that certain desirable traits are represented in successive generations.
Natural Selection -> The process in nature by which, according to Darwin's theory of evolution, only the organisms best adapted to their environment tend to survive and submit their genetic characteristics in increasing numbers to succeeding generations. |
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Term
| Explain why an individual organism cannot evolve. |
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Definition
| Natural selection occurs through interactions between individual organisms and their environments. There is little evidence that acquired traits can be inherited by their offspring. Rather, it is the heritable traits that are either amplified or diminished via natural selection. |
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Term
| Explain how the existence of homologous and vestigial structures can be explained by Darwin's theory of natural selection. |
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Definition
| Homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor. Vestigial structures are remnants or features that served important functions in the organisms ancestors. The existence of these structures are explained by natural selection because they held determine the evolutionary tree from which they came. |
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Term
| Explain how evidence from biogeography supports the theory of evolution by natural selection. |
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Definition
| The theory of biogeography supports natural selection because it shows that organisms had the same origin, but adapted to their particular surroundings. |
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Term
| Explain why natural selection can act only on heritable traits. |
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Definition
| In natural selection, organisms that are better suited to survival and reproduction with pass their genes on to the next generation. Only heritable traits, that can be passed on, have any affect over the next generation. |
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Term
| Explain the problem with the statement that Darwinism is “just a theory”. Distinguish between the scientific and colloquial use of the word “theory”. |
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Definition
| There's too much evidence about Darwinism. The scientific meaning of theory would be; That It's a well-substantiated, well-supported, well-documented explanation for our observations. The word theory in colloquial use is closer to the concept of a hypothesis in science. |
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