24.4 Speciation can occur rapidly or slowly and can result from changes in few or many genes Flashcards
44) According to the concept of punctuated equilibrium, the ʺsuddenʺ appearance of a new species in the fossil record means that
A) the species is now extinct.
B) speciation occurred instantaneously.
C) speciation occurred in one generation.
D) speciation occurred rapidly in geologic time.
E) the species will consequently have a relatively short existence, compared with other species.
D) speciation occurred rapidly in geologic time.
45) According to the concept of punctuated equilibrium,
A) natural selection is unimportant as a mechanism of evolution.
B) given enough time, most existing species will branch gradually into new species.
C) a new species accumulates most of its unique features as it comes into existence.
D) evolution of new species features long periods during which changes are occurring,
interspersed with short periods of equilibrium, or stasis.
E) transitional fossils, intermediate between newer species and their parent species,should be abundant.
C) a new species accumulates most of its unique features as it comes into existence.
46) Which of the following would be a position held by an adherent of the punctuated equilibrium theory?
A) A new species forms most of its unique features as it comes into existence and then changes little for the duration of its existence.
B) One should expect to find many transitional fossils left by organisms in the process of forming new species.
C) Given enough time, most existing species will gradually evolve into new species.
D) Natural selection is unimportant as a mechanism of evolution.
A) A new species forms most of its unique features as it comes into existence and then changes little for the duration of its existence.
47) Speciation
A) occurs at such a slow pace that no one has ever observed the emergence of new
species.
B) occurs only by the accumulation of genetic change over vast expanses of time.
C) must begin with the geographic isolation of a small, frontier population.
D) proceeds at a uniform tempo across all taxa.
E) can involve changes involving a single gene.
E) can involve changes involving a single gene.
48) Which of the following statements about speciation is correct?
A) The goal of natural selection is speciation.
B) When reunited, two allopatric populations will not interbreed.
C) Natural selection chooses the reproductive barriers for populations.
D) Prezygotic reproductive barriers usually evolve before postzygotic barriers.
E) Speciation is a basis for understanding macroevolution.
E) Speciation is a basis for understanding macroevolution.
49) Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species?
A) one that affects the rate of chlorophyll a synthesis
B) one that affects the amount of growth hormone synthesized per unit time
C) one that affects the compatibility of male pollen and female reproductive parts
D) one that affects the average depth to which roots grow down through the soil
E) one that affects how flexible the stems are
C) one that affects the compatibility of male pollen and female reproductive parts
50) In order for speciation to occur, what is true?
A) The number of chromosomes in the genome must change.
B) Changes to centromere location or chromosome size must occur within the genome.
C) Large numbers of genes that affect a single phenotypic trait must change.
D) Large numbers of genes that affect numerous phenotypic traits must change.
E) At least one gene, affecting at least one phenotypic trait, must change.
E) At least one gene, affecting at least one phenotypic trait, must change.
1) The largest unit within which gene flow can readily occur is a A) population.
B) species.
C) genus.
D) hybrid.
E) phylum.
B) species.
2) Bird guides once listed the myrtle warbler and Audubonʹs warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?
A) The two forms interbreed often in nature, and their offspring have good survival and reproduction.
B) The two forms live in similar habitats.
C) The two forms have many genes in common.
D) The two forms have similar food requirements.
E) The two forms are very similar in coloration.
B) The two forms live in similar habitats.
3) Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian islands have different elaborate courtship rituals that involve fighting other males and stylized movements that attract females. What type of reproductive isolation does this represent?
A) habitat isolation
B) temporal isolation
C) behavioral isolation
D) gametic isolation
E) postzygotic barriers
C) behavioral isolation
4) Which of the following factors would not contribute to allopatric speciation?
A) A population becomes geographically isolated from the parent population.
B) The separated population is small, and genetic drift occurs.
C) The isolated population is exposed to different selection pressures than the ancestral population.
D) Different mutations begin to distinguish the gene pools of the separated populations.
E) Gene flow between the two populations is extensive.
E) Gene flow between the two populations is extensive.
5) Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be
A) 12.
B) 14.
C) 16.
D) 28.
E) 56.
D) 28.
6) According to the punctuated equilibria model,
A) natural selection is unimportant as a mechanism of evolution.
B) given enough time, most existing species will branch gradually into new species.
C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.
D) most evolution occurs in sympatric populations.
E) speciation is usually due to a single mutation.
C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.
