LSU BIOL 1202 (HRINCEVICH) CH 24 HW

The appearance of an evolutionary novelty promotes _____. A. gene flow B. adaptive radiation C. paedomorphosis D. mutation E. mass extinction

B. adaptive radiation

Gametes from two plant species combine and produce a haploid zygote, and that zygote develops into a haploid, hybrid plant. Why is the hybrid plant sterile? Select all that apply. 1. Meiosis cannot occur. 2. The cells do not contain homologous chromosomes. 3. The plant cannot grow and reproduce asexually. 4. The gametes produced cannot combine with the gametes of other plants. 5. Mitosis cannot occur.

1 and 2

Use the data provided in the table to calculate the percent frequency of the +/+ genotype in A. gambiae over time (from pre-2006 to post-2006). Note that "frequency" refers to the proportional representation of an allele or genotype in a population. Indicate the percent frequency of the +/+ genotype in A. gambiae during the periods specified. 1. Pre-2006 2. 2006 3. Post-2006

1. 30.0% 2. 34.8% 3. 4.8%

Based on these data alone, which of the following conclusions is consistent with the observed changes in genotypic frequency for A. gambiae and A. coluzzii? 1. The r allele was present in A. gambiae before 2006 and increased over time because individuals with the r allele are resistant to insecticides and pass their resistant genes to new generations. 2. The r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations after hybrid individuals carrying the r allele were observed in 2006. This suggests that A. gambiae ×× A. coluzzii hybrids mated with A. coluzzii individuals, leading to the transfer of the adaptive allele r into A. coluzzii populations. 3. The r allele was present in both A. gambiae and A. coluzzii before 2006 so the impact of hybridization on the transfer of the r allele cannot be assessed.

1. The r allele was present in A. gambiae before 2006 and increased over time because individuals with the r allele are resistant to insecticides and pass their resistant genes to new generations. 2. The r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations after hybrid individuals carrying the r allele were observed in 2006. This suggests that A. gambiae ×× A. coluzzii hybrids mated with A. coluzzii individuals, leading to the transfer of the adaptive allele r into A. coluzzii populations.

Plant species F has a diploid number of 8. Plant species G has a diploid number of 10. What would be the diploid number of an allopolyploid hybrid of species F and species G? Enter your answer as a whole number.

18

What is genetic drift? A. A change in allele frequencies caused by random events B. The physical splitting of a habitat C. The production of an evolutionarily independent group of organisms D. The motion of continental plates over time

A. A change in allele frequencies caused by random events

A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time? A. Increased fitness of large-beaked birds, leading to natural selection B. Decreased fitness of small-beaked birds, creating a new species C. Increased fitness of the large-beaked birds, creating a new species D. Decreased fitness of the insects, allowing the birds to catch them more easily

A. Increased fitness of large-beaked birds, leading to natural selection

The sequence of events illustrated in this figure results in a fertile hybrid plant called an allopolyploid. Which of the following statements is the most complete description of an allopolyploid? A. It contains more than two sets of chromosomes, which are derived from two species. B. It contains more than one pair of homologous chromosomes. C. It contains more than two sets of chromosomes, which are derived from a single species. D. It is able to sexually reproduce with two or more other plant species because of its diverse set of chromosomes.

A. It contains more than two sets of chromosomes, which are derived from two species.

Which of the following statements about reinforcement is true? A. Reinforcement is a type of natural selection. B. Reinforcement increases the number of intermediate phenotypes. C. Reinforcement decreases the morphological difference between two incipient species. D. Reinforcement is also called dispersive selection.

A. Reinforcement is a type of natural selection.

Based on these observations, do you think that the number of malaria cases will increase, decrease, or stay the same in the future? A. The number of malaria cases will increase. B. The number of malaria cases will stay the same. C. The number of malaria cases will decrease.

A. The number of malaria cases will increase.

Mass extinctions create conditions that promote _____. A. adaptive radiation B. genetic drift C. microevolution D. paedomorphosis E. gene flow

A. adaptive radiation

Hybrid zones provide an opportunity to investigate _____. A. the evolution of reproductive isolation B. mutations C. punctuated equilibrium D. polyploidy E. allopatric speciation

A. the evolution of reproductive isolation

_____ is rapid speciation under conditions in which there is little competition. A. Gene flow B. Adaptive radiation C. Genetic drift D. Microevolution E. Paedomorphosis

B. Adaptive radiation

A certain species of salamander was split into two populations by a wide, dry valley, and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as _____. A. speciation B. fusion C. punctuated equilibrium D. reinforcement E. stability

B. fusion

According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods. A. adaptive radiation B. punctuated equilibrium C. nondisjunction D. geographic isolation E. gradualist

B. punctuated equilibrium

Three of the most prominent definitions of species are the biological species concept, the phylogenetic species concept, and the morphological species (morphospecies) concept. Drag each characteristic to the appropriate bin based on the species concept(s) to which it applies.

Biological: Not applicable for extinct species Morphological: Relies on similarities in structure Phylogenetic: Based on evolutionary history Morphological and Phylogenetic: Accommodates asexual reproduction Species acceptance criteria can be subjective Morphological, Phylogenetic, and Biological: Used by scientists in classification

Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? A. Genetic drift occurred in the two populations. B. The separation of habitats reduced gene flow between the populations. C. All three answers are correct. D. Natural selection favored individuals that were more fit in the new environment.

C. All three answers are correct.

Which of the following best describes the change in kdr genotype frequencies over time in A. coluzzii? A. From pre-2006 to post-2006, the frequency of the +/+ genotype increased dramatically while the frequencies of +/r and r/r genotypes decreased. B. From pre-2006 to post-2006, the frequency of the r/r genotype increased dramatically while the frequencies of +/+ and +/r genotypes decreased dramatically. C. From pre-2006 to post-2006, the frequencies of the r/r and +/r genotypes increased dramatically while the frequency of +/+ decreased dramatically. D. From pre-2006 to post-2006, there was little change to the r/r, +/+, and +/r genotype frequencies.

C. From pre-2006 to post-2006, the frequencies of the r/r and +/r genotypes increased dramatically while the frequency of +/+ decreased dramatically.

Which of the following best describes the change in kdr genotype frequencies over time in A. gambiae? A. From pre-2006 to post-2006, the frequency of the r/r genotype increased dramatically while the frequencies of +/+ and +/r genotypes remained relatively constant. B. From pre-2006 to post-2006, there was little change to the r/r, +/+, and +/r genotype frequencies. C. From pre-2006 to post-2006, the frequency of the r/r genotype increased dramatically while the frequencies of +/+ and +/r genotypes decreased dramatically. D. From pre-2006 to post-2006, the frequency of the r/r genotype increased slightly while the frequencies of +/+ and +/r genotypes decreased dramatically.

C. From pre-2006 to post-2006, the frequency of the r/r genotype increased dramatically while the frequencies of +/+ and +/r genotypes decreased dramatically.

A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to itsoriginal habitat. Which of the following statements about these bird populations is true? A. The birds were separated by a vicariance event. B. The populations will be able to interbreed even though they are different species. C. The populations will not be able to interbreed because they are different species. D. The populations were sympatric while they diverged.

C. The populations will not be able to interbreed because they are different species.

What role does nondisjunction play in the formation of a fertile allopolyploid hybrid? A. It causes the chromosomes to line up at the center of the cell during mitosis. B. It allows gametes of the two parent species to combine. C. It breaks down chromosomes that don't exist as homologous pairs. D. It doubles the chromosome number in the hybrid.

D. It doubles the chromosome number in the hybrid.

Do these observations indicate that hybridization can lead to the transfer of adaptive alleles? A. Yes; the r allele was present in A. coluzzii before 2006 and after 2006, suggesting that the A. coluzzii population is resistant to insecticides. B. No; the r allele was present in A. coluzzii before 2006, so we cannot assess the impact of hybridization on the transfer of the r allele. C. No; mosquito species cannot hybridize and exchange alleles. D. Yes; the r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations once hybrid individuals carrying the r allele were observed in 2006.

D. Yes; the r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations once hybrid individuals carrying the r allele were observed in 2006.

Two animals are considered members of different species if they _____. A. look different B. are geographically isolated C. live in different habitats D. cannot mate and produce viable, fertile offspring E. are members of different populations

D. cannot mate and produce viable, fertile offspring

The different finch species found on the Galápagos Islands probably arose as a result of _____. A. artificial selection B. mass extinction C. paedomorphosis D. gene flow E. adaptive radiation

E. adaptive radiation

Feathers either play a role, or may have played a role, in _____. A. courtship B. gliding C. flight D. extended hops E. all of these

E. all of these

What is the most important factor that holds a gene pool of a species together and prevents speciation? A. hybridization B. prezygotic barriers C. sexual selection D. behavioral isolation E. gene flow

E. gene flow

True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.

False

Recall that the biological species concept defines a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring. This means that all members of these populations (called conspecifics) can contribute to a common gene pool. Conspecifics are organisms or populations that belong to the same species. Genes are transferred between conspecific populations through both direct and indirect gene flow. Biologists studying disease susceptibility in mice used genetic techniques to look for gene flow in 12 wild populations of mice. The populations (designated A through L) were located along a 210-km transect line. The researchers found evidence of gene flow between some, but not all, pairs of populations. In the grid below, a "+" indicates a pair of populations in which direct gene flow was detected, and a "-" indicates a pair that showed no evidence of direct gene flow. For help reading this grid, see Hint 2. The researchers discovered that the 12 populations could be organized into 3 distinct species. Populations A, B, and C each belong to a different species. Use the data in the grid to sort each population to the species to which it belongs.

Species 1: K D F H I Species 2: LE Species 3: G J

True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation.

True

Classifying reproductive barriersAccording to the biological species concept, individuals belong to the same species if they can interbreed in nature and produce viable, fertile offspring. Prezygotic and postzygotic barriers ensure that members of different species do not reproduce with one another. This diagram shows some of these barriers along with examples of the barriers at work.Complete the diagram by following these steps:Drag blue labels onto blue targets only to identify the two main types of reproductive barriers.Drag pink labels onto pink targets only to identify specific barriers.Drag white labels onto white targets only to identify examples of barriers

a. prezygotic barriers b. postzygotic barrirs c. behavior isolation d. mechanical isolation e. temporal isolation f. gametic isolation g. reduced hybrid fertility h. 2 fish species spawn at diff. depths i. a coral's sperm can't fertilize another's eggs j. offspring of 2 newts are sterile k. lion-tiger hybrids don't reach maturity