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44 Cards in this Set
- Front
- Back
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Evolution
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1) The change in life over time by adaptation, variation, over-reproduction, and differential survival/reproduction, a process referred to by Charles Darwin and Alfred Wallace as natural selection. 2) Descent with modification.
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gene pool
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The sum of all the genetic information carried by members of a population
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Fitness
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A measure of an individual's ability to survive and reproduce; the chance that an individual will leave more offspring in the next generation than other individuals
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Adaptation
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Tendency of an organism to suit its environment; one of the major points of Charles Darwin's theory of evolution by natural selection: organisms adapt to their environment. Those organisms best adapted will have a greater chance of surviving and passing their genes on to the next generation.
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Diversity
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The different types of organisms that occur in a community
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Variation
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differences in morphology, physiology, or behavior among individuals of a species; caused by genetic and environmental factors; only genetic variation is affected by natural selection.
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selective breeding
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The selection of individuals with desirable traits for use in breeding. Over many generations, the practice leads to the development of strains with the desired characteristics
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artificial selection
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The process in which breeders choose the variants to be used to produce succeeding generations.
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genetic drift
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Random changes in the frequency of alleles from generation to generation; especially in small populations, can lead to the elimination of a particular allele by chance alone.
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Mutation
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Any heritable change in the nucleotide sequence of DNA; can involve substitutions, insertions, or deletions of one or more nucleotides.
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divergent
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The divergence of a single interbreeding population or species into two or more descendant species.
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Convergent
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The development of similar structures in distantly related organisms as a result of adapting to similar environments and/or strategies of life. Example: wings of birds and insects, the body shape of dolphins, sharks, and the extinct marine reptiles known as ichthyosaurs.
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Speciation
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formation of new species through natural selection; occurs when selective force is intense; accounts for diversity of living things on planet today.
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adaptive radiation
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The development of a variety of species from a single ancestral form; occurs when a new habitat becomes available to a population. Evolutionary pattern of divergence of a great many taxa from a common ancestral species as a result of novel adaptations or a recent mass extinction. Examples: mammals during the Cenozoic Era after the extinction of dinosaurs at the close of the Mesozoic Era flowering plants during the Cretaceous Period diversified because of their reproductive advantages over gymnosperm and non-seed plants that dominated the floras of the world at that time.
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Coevolution
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The process by which two or more organisms develop specialized traits and characteristics in accordance with the other. Species which have coevolved with each other usually depend on each other for survival.
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• Gradualism
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o Theory that postulates that evolution is primarily microevolutionary, with new variation arising in individuals by mutation and recombination, and natural selection acting primarily on individuals and populations.
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• punctuated equilibrium
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o A model that holds that the evolutionary process is characterized by long periods with little or no change interspersed with short periods of rapid speciation.
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• Homologous
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o Body parts in different organisms that have similar bones and similar arrangements of muscles, blood vessels, and nerves and undergo similar embryological development, but do not necessarily serve the same function; e.g., the þipper of a whale and the forelimb of a horse.
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• analogous
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o Body parts that serve the same function in different organisms, but differ in structure and embryological development; e. g., the wings of insects and birds.
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• Vestigial
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o Nonfunctional remains of organs that were functional in ancestral species and may still be functional in related species; e.g., the dewclaws of dogs
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a. Theory of Acquired Traits
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i. theory that acquired traits can be inherited.
ii. The hereditary mechanism by which changes in physiology acquired over the life of an organism (such as muscle enlarged through use) are purportedly transmitted to offspring 1. Ex: Fiddler crab 2. Ex: Giraffe neck |
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b. Law of Use and Disuse
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i. use or disuse causes structures to enlarge or shrink -- Lamarck called the "First Law" in his book Philosophie zoologique. Lamarck's "Second Law" stated that all such changes were heritable. The result of these laws was the continuous, gradual change of all organisms, as they became adapted to their environments; the physiological needs of organisms, created by their interactions with the environment, drive Lamarckian evolution.
1. Ex: Fiddler crab 2. Ex: Giraffe neck |
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a. How do Homologous Structures provide evidence for evolution?
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i. Inferences about common descent derived from paleontology are reinforced by comparative anatomy. For example, the skeletons of humans, mice, and bats are strikingly similar, despite the different ways of life of these animals and the diversity of environments in which they flourish. The correspondence of these animals, bone by bone, can be observed in every part of the body, including the limbs; yet a person writes, a mouse runs, and a bat flies with structures built of bones that are different in detail but similar in general structure and relation to each other.
ii. Scientists call such structures homologies and have concluded that they are best explained by common descent. Comparative anatomists investigate such homologies, not only in bone structure but also in other parts of the body, working out relationships from degrees of similarity. Their conclusions provide important inferences about the details of evolutionary history, inferences that can be tested by comparisons with the sequence of ancestral forms in the paleontological record. |
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b. How do embryonic development provide evidence for evolution?
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i. Embryology, the study of biological development from the time of conception, is another source of independent evidence for common descent. Barnacles, for instance, are sedentary crustaceans with little apparent similarity to such other
crustaceans as lobsters, shrimps, or copepods. Yet barnacles pass through a free-swimming larval stage in which they look like other crustacean larvae. The similarity of larval stages supports the conclusion that all crustaceans have homologous parts and a common ancestry.
ii. Similarly, a wide variety of organisms from fruit flies to worms to mice to humans have very similar sequences of genes that are active early in development. These genes influence body segmentation or orientation in all these diverse groups. The presence of such similar genes doing similar things across such a wide range of organisms is best explained by their having been present in a very early common ancestor of all of these groups. |
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c. How do fossils provide evidence for evolution?
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i. Although it was Darwin, above all others, who first marshaled convincing evidence for biological evolution, earlier scholars had recognized that organisms on Earth had changed systematically over long periods of time. For example, in 1799 an engineer named William Smith reported that, in undisrupted layers of rock, fossils occurred in a definite sequential order, with more modern-appearing ones closer to the top. Because bottom layers of rock logically were laid down earlier and thus are older than top layers, the sequence of fossils also could be given a chronology from oldest to youngest. His findings were confirmed and extended in the 1830s by the paleontologist William Lonsdale, who recognized that fossil remains of organisms from lower strata were more primitive than the ones above. Today, many thousands of ancient rock deposits have been identified that show corresponding successions of fossil organisms.
ii. Thus, the general sequence of fossils had already been recognized before Darwin conceived of descent with modification. But the paleontologists and geologists before Darwin used the sequence of fossils in rocks not as proof of biological evolution, but as a basis for working out the original sequence of rock strata that had been structurally disturbed by earthquakes and other forces. |
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d. How do Similar sequences of DNA provide evidence for evolution?
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i. The unifying principle of common descent that emerges from all the foregoing lines of evidence is being reinforced by the discoveries of modern biochemistry and molecular biology.
ii. The code used to translate nucleotide sequences into amino acid sequences is essentially the same in all organisms. Moreover, proteins in all organisms are invariably composed of the same set of 20 amino acids. This unity of composition and function is a powerful argument in favor of the common descent of the most diverse organisms. |
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a. On Charles Darwin’s voyage on the HMS Beagle What did he do?
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i. While on his voyage around the world aboard the H.M.S. Beagle Charles Darwin spent about one month observing life on the Galapagos Islands
ii. There, he encountered some unique animals, such as Finches and Tortises |
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b. On Charles Darwin’s voyage on the HMS Beagle What did he observe?
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i. The Galapagos Islands are close together but have very different climate. Some were hot and dry, with little vegetation. Others had more rainfall and were rich in vegetation
ii. Each island had its own unique assortment of plant and animal species. |
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c. On Charles Darwin’s voyage on the HMS Beagle What did he conclude
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i. After his voyage, Darwin spent a great deal of time thinking about his findings.
ii. He began to wonder if animals living on different islands had once been members of the same species that had developed different characteristics after becoming isolated from one another in different habitats. |
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4. What does it mean to be “fit” with regards to “Survival of the fittest”?
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a. Endowed with phenotypic characteristics which improve chances of survival and reproduction
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5. Discuss the components of the Theory of Natural Selection
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a. 1. The individual organisms that make up a population vary in the traits they possess, such as their size and shape.
i. Which means that each individual organism in a population have very distinct traits such as tall & short; blue eyes vs. brown eyes b. 2. Some of the trait differences are passed on to offspring. i. For example, Tall parents may tend to have tall offspring c. This means the trait (tall) has some genetic basis and is inheritable d. 3. Only a subset of the offspring that are produced in each generation survives long enough to reproduce, and of the individuals that reproduce, not all produce the same number of offspring. Thus, some individuals in the population produce more offspring than others do. i. Only those who survive are allowed to reproduce & not all that reproduce do it the same way e. 4. The subset of individuals that produce the most offspring is not a random sample of the population. Instead, individuals with certain traits are more likely to produce the greatest number of offspring in a given environment. The individuals with these traits are Naturally Selected i. It is Not the number of offspring you produce that gives your genes the best chance of survival, it is WHICH genes you have that decides your chances |
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a. What influences did Thomas Malthus have on Darwin?
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i. population growth would always overpower food supply growth, creating perpetual states of hunger, disease, and struggle. The natural, ever-present struggle for survival caught the attention of Darwin, and he extended Malthus' principle to the evolutionary scheme.
ii. He observed that babies were being born faster than people were dying. He reasoned that if the human population continued to grow, sooner or later there would be insufficient space and food. |
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b. What influences did Alfred Wallace have on Darwin?
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i. He is best known for independently proposing a theory of natural selection which prompted Charles Darwin to publish on his own theory. Wallace was also one of the leading evolutionary thinkers of the 19th century who made a number of other contributions to the development of evolutionary theory
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c. What influences did Gregor Mendel have on Darwin?
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i. Mendel, so the argument goes, had set out to refute Darwin’s postulations and, as an exponent of a theological world view, to demonstrate that change can also occur as the result of cross-breeding.
ii. Nineteenth-century theologians regarded Darwin’s "Origin of the Species" as a frontal assault on the dogma of God’s creation of mankind. It was not until 1951 that Pope Pius XII paved the way for an open discussion of evolution within the church. The truly innovative and original idea in Darwin’s work was the concept of population, from which the theory of natural selection proceeded. Heredity in Mendel’s terms, however, far from producing evolutionary change, results in perfectly predictable segregation ratios. |
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a. selective breeding
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i. The selection of individuals with desirable traits for use in breeding. Over many generations, the practice leads to the development of strains with the desired characteristics.
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b. natural variation
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i. Populations vary in the types of individuals and their reproductive success. Those individuals that leave more offspring behind than others pass on more of their alleles and have a better success rate in dominating the population.
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c. artificial selection
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i. The process in which breeders choose the variants to be used to produce succeeding generations.
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8. List some physical and behavioral adaptations.
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a. Physical adaptations
i. Speed ii. Camouflage iii. Claws iv. quills b. Behavioral adaptations i. Solitary ii. Herds iii. Packs iv. activity |
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9. Compare the three types of selection and identify them as a graph: directional, stabilizing, and disruptive selection.
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a. Directional selection
i. A process of natural selection that tends to favor phenotypes at one extreme of the phenotypic range. b. Stabilizing selection i. A process of natural selection that tends to favor genotypic combinations that produce an intermediate phenotype; selection against the extremes in variation. c. disruptive selection i. A process of natural selection that favors individuals at both extremes of a phenotypic range. |
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10. Compare divergent evolution with convergent evolution.
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a. divergent evolution
i. The divergence of a single interbreeding population or species into two or more descendant species. b. convergent evolution. i. The development of similar structures in distantly related organisms as a result of adapting to similar environments and/or strategies of life. Example: wings of birds and insects, the body shape of dolphins, sharks, and the extinct marine reptiles known as ichthyosaurs. |
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11. How do the finches on the Galapagos Islands exhibit adaptive radiation?
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a. The Galapagos finches evolved through natural selection from a common ancestor into a wide variety of different looking species with different kinds of beaks
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12. What is the difference between homologous and analogous structures?
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a. Homologous structures
i. Body parts in different organisms that have similar bones and similar arrangements of muscles, blood vessels, and nerves and undergo similar embryological development, but do not necessarily serve the same function; e.g., the þipper of a whale and the forelimb of a horse. b. analogous structures i. Body parts that serve the same function in different organisms, but differ in structure and embryological development; e. g., the wings of insects and birds. |
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13. What is the Hardy-Weinberg Theorem?
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a. This idea was developed to determine if a population was evolving. The authors of the theorem set up a series of parameters, which do not exist in nature, to be followed when determining the allele frequencies of any population.
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14. What are the Hardy-Weinberg Theorem’s guidelines?
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1. No mutations must occur so that new alleles do not enter the population.
2. No gene flow can occur (i.e. no migration of individuals into, or out of, the population). 3. Random mating must occur (i.e. individuals must pair by chance) 4. The population must be large so that no genetic drift (random chance) can cause the allele frequencies to change. 5. No natural selection can occur so that certain alleles are not selected for, or against |
