Exam 1 review Flashcards
RNA molecules can both carry genetic information and be catalytic. This supports the proposal that
RNA was the first hereditary information.
Which of the following is the correct sequence of these events in the origin of life?
I.formation of protocells
II.synthesis of organic monomers
III.synthesis of organic polymers
IV. formation of DNA-based genetic systems
II, III, I, IV
In peas, a gene controls flower color such that R = purple is dominant to 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(frequency of r) for this population?
0.8
A defining characteristic of allopatric speciation is
geographic isolation.
In bionomial nomenclature where humans are : Homo sapiens, sapiens is the:
species
No two people are genetically identical, except for identical twins. The chief cause of genetic variation among human individuals is
he reshuffling of alleles in sexual reproduction.
Which statement about natural selection is most correct?
Question options:
Well-adapted individuals leave more offspring, and thus contribute more to the next generation’s gene pool, than do poorly adapted individuals.
Adaptations beneficial at one time should generally be beneficial during all other times as well.
Different species that occupy the same habitat will adapt to that habitat by undergoing the same genetic changes.
Natural selection is the sole means by which populations can evolve.
Well-adapted individuals leave more offspring, and thus contribute more to the next generation’s gene pool, than do poorly adapted individuals.
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.7. What is the percentage of the population that is homozygous for this allele?
49
Who was the naturalist who synthesized a concept of natural selection independently of Darwin?
Alfred Wallace
Which of the following must exist in a population before natural selection can act upon that population?
Question options:
genetic variation among individuals
variation among individuals caused by environmental factors
sexual reproduction
A and C only
A, B, and C
genetic variation among individuals
Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations?
Natural selection
“Improving the intelligence of an adult through education will result in that adult’s descendants being born with a greater native intelligence.” This statement is the idea of:
Lamarck
In evolutionary terms, the more closely related two different organisms are, the
more recently they shared a common ancestor.
If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-eighth the normal proportion of carbon-14 to carbon-12 should be about how many years old?
17,190
The theory of evolution is most accurately described as
a scientific explanation, supported by much evidence, for how populations change over time.
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
28
DDT was once considered a “silver bullet” that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. What would need to be true for pest eradication efforts to have been successful in the long run?
All individual insects should have possessed genomes that made them susceptible to DDT.
In peas, a gene controls plant height such that T=tall and t=dwarf (T is completely dominant to t). In a isolated population, 91% of the population is tall while the rest are dwarf. Assume the population is in Hardy-Weinberg equilibrium. i. What is the allele frequency for this population ? ii. Calculate the proportion of each genotype.
p=0.7 q=0.3
TT=0.49
Tt=0.42
tt=0.09
What would be the best technique for determining the evolutionary relationships among several closely related species, each of which still contains living members?
DNA or protein analysis
What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth?
DNA is chemically more stable and replicates with fewer errors (mutations) than RNA.
List 2 lines of evidence supporting the endosymbiont theory!
1.Mitochondria and chloroplasts have their own DNA which is similar to the DNA in other prokaryotes
- Mitochondria and chloroplasts replicate, translate, translate their DNA much like other prokaryotes
Which of these conditions should completely prevent the occurrence of natural selection in a population over time?
All variation between individuals is due only to environmental factors.
Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?
directional selection
A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. What inferences might you make about this population?
The amount of available food may have increased.
The number of predators may have decreased.
The squirrels of subsequent generations should show greater levels of variation than previous generations because squirrels that would not have survived in the past will now survive.
A and B only
A, B, and C
A, B, and C
