What is true of microevolution?
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations
The original source of all genetic variation is`
Mutation
Which of the following is the best modern definition of evolution?
Descent with modification
Microevolutions occur when
changes in allele frequencies in a population occur over generations
Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true
Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted
Consider a population of wildflowers in which the frequency of the red allele CR is p = 0.7.
What is the frequency of the white allele (CW ) in this population?
0.3
This Punnett square shows allele combinations for all possible genetic crosses in the wildflower population described in Part A.What are the expected genotype frequencies in the offspring generation (Cr=0.7, Cw= 0.3)
0.49 CRCR (red flowers), 0.42 CRCW (pink flowers), 0.09 CWCW (white flowers)
Consider a wildflower population with the following allele and genotype frequencies.
Frequency of the CR allele: p = 0.6
Frequency of the CW allele: q = 0.4
Frequency of CRCR : 50%
Frequency of CRCW : 20%
Frequency of CWCW : 30%
Is this population in Hard
No, the CRCW frequency is too low
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
Sexual Reproduction
Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the H
A1= 0.97
A2=0.03
Which Hardy-Weinberg condition is affected by population size?
Genetic Drift
Which one of the following conditions would allow gene frequencies to change by chance?
Small populations
Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus, _____
the allele's frequency should not change from one generation to the next
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the frequency of individuals that are homozygous for this allele?
0.09
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype?
0.81
You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?
Allele frequency cannot be determined from this information.
In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?
0.8
Do problem 16 in the first mastering once more
...
The evolutionary effects of genetic drift are greatest when
The population size is small
In 1983, a population of dark-eyed junco birds became established on the campus of the University of California, San Diego (UCSD), which is located many miles from the junco's normal habitat in the mixed-coniferous temperate forests in the mountains. Junc
A founder effect
An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the g
A genetic bottleneck
In evolutionary terms, an organism's fitness is measured by its
Contribution to the gene pool of the next generation
Blue poppies native to China were grown at a plant-breeding center in California. The plants with the thickest leaves were most likely to survive and reproduce in the drier climate. After several generations, the percentage of thick-leaved plants had incr
Directional selection
What is the only evolutionary mechanism that consistently leads to adaptive evolution?
Natural selection
Martin Wikelski and L. Michael Romero (Body size, performance and fitness in Gal�pagos marine iguanas, Integrative and Comparative Biology 43 [2003]:376-86) measured the snout-to-vent (anus) length of Gal�pagos marine iguanas and observed the percent surv
Stabalizing selection
Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?
Stabalizing selection
Natural selection changes allele frequencies because some _______ survive and reproduce more successfully than others
Individuals
No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is
The reshuffling of alleles during sexual reproduction
You read about soapberry bugs and select the correct statement describing relative fitness in these individuals.
A soapberry bug with high relative fitness has a relatively high number of offspring that survive to reproductive age.
Which statement correctly describes the role of chance in evolution?
The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA
Darwin and Wallace's theory of evolution by natural selection was revolutionary because it
dismissed the idea that species are constant and emphasized the importance of variation and change in populations
Fossils found in strata reveal that
older strata carry fossils that differ greatly from living organisms
Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is
a few thousand years old, and populations are unchanging
Which of the following statements best explains why modification or change in an organ or tissue during the lifetime of an individual is not inherited?
Characteristics acquired during an organism's life are generally not passed on through genes.
When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species
Occurs, but that there is no evolution
For which one of the following observations were both Lamarck's hypothesis and Darwin's hypothesis in complete agreement?
Gradual evolutionary change explains why organisms are well-suited
to their environments.
An adaptation is _____
a trait that gives an organism a reproductive advantage in the current environment
Which of the following observations led to Darwin's major inferences?
1.Members of a population vary in their heritable traits.
4.Although organisms can produce huge numbers of offspring, many of these offspring do not survive
(First and fourth are correct).
A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gra
The percentage of molted fish will increase over time
In Darwin's tree of life, each fork in the tree represents ________
the most recent common ancestor of the subsequent branches
Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct?
In this wild mustard, there is enough heritable variation to permit these different varieties.
What are adaptations?
inherited characteristics of organisms that enhance their survival
Which of these conditions are always true of populations evolving due to natural selection?
Condition 1: The population must vary in traits that are heritable.
Condition 2: Some heritable traits must increase reproductive success.
Condition 3: Individuals
Conditions 1 and 2
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the
Triazine-resistant weeds were more likely to survive and reproduce.
After the drought of 1977, researchers hypothesized that on the Gal�pagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cisto
increased variation in beak size and shape over time
Darwin used the phrase "descent with modification" to explain ________.
evolution of the unity and diversity of life
Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection?
1. Well-adapted individuals leave more offspring than do poorly adapted individuals.
2. A change occurs in t
2 ? 4 ? 1 ? 3
Which of the following statements describe the effect of evolution on a population?
increasingly better match between a population and its environment
Which of Darwin's ideas had the strongest connection to his reading of Malthus's essay on human population growth?
Struggle for existence
If Darwin had been aware of genes and their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?
If natural selection can change gene frequency in a population over generations, given enough time and genetic diversity, then natural selection can cause sufficient genetic change to produce new species from old ones.
Currently, two extant elephant species (X and Y) are classified in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?
Species X and Y share a greater number of homologies with each other than either does with species Z.
Varieties of Staphylococcus aureus that are resistant to the drug methicillin _____
already existed in the population before methicillin was developed
&
were strongly selected for as methicillin became widely used to treat bacterial infections
(2nd & 4th answer are correct
A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____.
embryos of dissimilar organisms, such as sharks and humans, resemble each other
The theory of evolution through natural selection is considered a scientific theory because
it is broad enough in scope to explain many observations
it is supported by a massive body of evidence from many disciplines
it is general enough to provide many testable hypotheses
(All of the above are correct.)
If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?
These bacteria would be outcompeted and replaced by bacteria that have lost these genes.
Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _____
Homology
Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
Which of the following evidence most strongly supports the common origin of all life on Earth? All organisms _____.
use essentially the same genetic code
What must be true of any organ described as vestigial?
It must be homologous to some feature in an ancestor.
About thirteen different species of finches inhabit the Gal�pagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen sp
Their genomes should be more similar to each other than are the genomes of the five tree finch species.
Which of the following is not an observation or inference on which natural selection is based?
Poorly adapted individuals never produce offspring.
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that
humans and chimpanzees share a relatively recent common ancestor.
In 1959, doctors began using the powerful antibiotic methicillin to treat infections of Staphylococcus aureus, but within two years, methicillin-resistant strains of S. aureus (MRSA) appeared. How did the resistant strains of S. aureus emerge?
Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individua
Soapberry bugs use needlelike "beaks" to feed on seeds within the fruits of various plants. Bugs feed most successfully when their beak length matches the size of the fruit on which they are feeding. For 25 years, populations of soapberry bugs in central
The action of natural selection on beak length in soapberry bug populations varies with the environment
What is true of microevolution?
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.