Chapter M.C. and Content Review

1. In his theory of evolution, Lamarck assumed that (a) useful characteristics that are acquired are inherited
2. Darwin’s theory of evolution is based on the concept of (c) natural selection
3. If a species of insect lacks the variations needed to adapt to a changing environment, it will most likely (b) become extinct
4. The special characteristics that make an organism particularly well suited to its environment are known as (d) adaptations
5. Which theory of evolutionary change suggests that species have long periods of stability interrupted by geologically brief periods of significant change during which new species are formed? (c) Punctuated equilibrium
6. Pigeons of the same species inhabiting a city park represent a (a) population
7. Natural selection acting on a normal distribution of phenotypes in which the fittest individuals correspond to the center of the graph is called (c) stabilizing selection
8. For speciation to take place, a population must evolve enough genetic changes so that (d) the emerging groups can interbreed
9. New species usually form only when populations (a) are isolated
10. The evolution of similar adaptations in unrelated species is called (b) convergent evolution
Content Review
11. Lamarck’s theory of evolution involved two principles. According to his first principle, the law of use and disuse, the more an animal uses a particular part of its body, the stronger and better developed that part becomes while at the same time, the less a part is used, the weaker and less developed it becomes. The second part of Lamarck’s theory was the inheritance of acquired characteristics, the idea that the characteristics an organism developed through use and disuse could be passed on to its offspring.
12. Darwin’s theory of evolution by natural selection, or the idea that nature “selects” its survivors, has six main points. He states species populations remain more or less constant because only a small fraction of offspring live long enough to reproduce, since living space and food are limited, offspring in each generation must compete among themselves and with other species for the necessities of life, and the characteristics of the individuals in any species vary, some variations not being important but others affects survival skills. He also states that because of variations, some individuals are better adapted to survive and reproduce than others so those individuals will have a greater chance of living long enough to reproduce and experience has shown that the offspring of better adapted individuals usually inherit these favorable variations. Over many generations, favorable adaptations gradually accumulate in the species and unfavorable ones disappear, eventually causing the accumulated changes to become so great that the net result is a new species.
13. Gradualism and punctuated equilibrium differ because the gradualism model sees evolution as proceeding more or less steadily through time while the punctuated equilibrium model views evolution as being concentrated in short periods of time followed by long periods of little or no change.
14. De Vries explained the appearance of new traits within a species by introducing the concept of mutation on research that he conducted over several years with the evening primrose. He observed that occasionally a plant appeared with a totally new structure or form. This plant would then breed true in later generations. De Vries considered these sudden changes in the hereditary material to be mutations.
15. Genetic drift is less likely to affect large populations than small ones because in a large population, there are many individuals. Therefore, it is unlikely that only a few individuals have an allele that no other individuals possess.
16. The Hardy-Weinberg law is useful in the way that it allows us to discover whether or not evolution is occurring in a population. If there is failure of the Hardy-Weinberg law, then it is a sign evolution is occurring, and that the extent of the variation prediction being a measure of how rapid the evolutionary change is.
17. The difference between camouflage and warning coloration is that in camouflage, the organism blends into the environment while in warning coloration, the colors of the animal actually make it easier to see.
18. Two groups of organisms are considered two different species when they cannot interbreed successfully.
19. Darwin’s finches may be said to represent an example of adaptive radiation because an ancestral type of finch probably arrived in the Galapagos Islands and then radiated into a variety of habitats and ways of life, such as living on the ground or in trees, feeding on seeds, insects, or berries, and without competition from other birds, the finches adapted to the various types of environment that were present to them.
20. The general conclusions drawn from studies of the peppered moth in England were that, even though the dominant peppered moth were light and the rare were dark, they rested on trees during the day. The lichens on the trees in pre-industrialized England were light and so the light peppered moth was offered more camouflage rather than the dark one and so the dark peppered moths were preyed upon more frequently and after England became industrialized, the fumes and soot killed the lichens and blackened the trees. This is turn offered the dark peppered moths more camouflage, and light peppered moths were preyed upon more frequently, causing dominance to occur in the dark peppered moths. In regions of England cleaner and nonindustrial, therefore, the light peppered moths continued to predominate.