Which of the following is most characteristic of a dominant gene?
It masks the effects of other alleles
Its effects are masked by other alleles
It always produces only one phenotypic effect
It is always the most prevalent in the gene pool

Which trait is most likely governed by a single gene?
Sickle-cell anemia
Obesity
Hair color
Skin color

If a plant that is heterozygous for tallness (Tt) is crossed with a homozygous tall plant (TT), which could not be among the offspring?
All tall plants
A Tt plant
A TT plant
A tt plant

Which of the following is not a prerequisite for natural selection's operation?
More offspring than can possibly survive
Differential reproduction
An innate desire to change
Competition for resources

Which statement best characterizes natural selection?
Blind, random chance hitting upon lucky combinations
The slow accumulation of adaptive mutations
Absolute dependence on carbon-based biochemistry
Organisms perishing when unexpected calamities occur

Which statement is true of artificial selection?
It is essentially the same process as natural selection
It is fundamentally different from natural selection
It is related to the domestication of animals, but not to agriculture
It was elaborated as a theory long after natural selection was first discussed

What is continued artificial selection's usual effect on genetic diversity?
It promotes additional variation for humans to choose from
It leads to the creation of genetically homogeneous populations
It causes maladaptive genes to be more common in the gene pool
It reinforces the close relationship between domestic and wild stocks

What type of molecule had to be formed on earth in order for life to evolve?
A molecule now found in modern life forms
A molecule containing carbon
A self-replicating molecule
An enzyme or other large protein

Which best exemplifies an active dead-end replicator?
A gene in a sperm cell
A gene in a body cell
A meme in the mind of an active individual
A computer virus on the internet

Why aren't organisms considered replicators?
They are macroscopic
They can act to maximize their own happiness rather than their number of offspring
They do not pass on their acquired characteristics; they only pass on their genes
They aren't the main unit of selection

Which is a true statement about the immune system?
It is unique to primates
The manufacture of immune-system cells uses the principle of natural selection
It isn't really very specific and simply attacks all pathogens the same way
It consists of only one mechanism of response to invasion

Which is characteristic of an "arms race" between the human immune system and an invading pathogen?
The immune system will eventually evolve to consistently defeat the pathogen
Beneficial changes to the immune system will generally be counteracted by changes in the pathogen, and vice versa
The pathogen will run amok through the human population
The pathogen will evolve to attack other species besides just humans

What is the most likely effect of killing 80% of a colony of bacteria with a certain antibiotic?
The remaining bacteria will re-grow into a new colony more resistant to the antibiotic
The remaining bacteria will die because of the drastic decimation
The bacteria will not cause any further infections because their numbers have been drastically reduced
The bacteria will try to start a new colony where the antibiotic will not be found

Which of the following is not a risk resulting from increased antibiotic resistance among bacteria?
We may not have any available treatment for certain bacterial diseases
We may be forced to administer antibiotics that are more dangerous or have more severe side effects than those used in the past
Resistant bacteria may share their resistance genes with other bacteria, thus exacerbating the problem
Humans may become more vulnerable to viral infection

How are DNA sequences spliced into rings of existing DNA?
The two DNA molcules are cut with restriction enzymes, then connected together with the use of additional enzymes
The DNA molecules are boiled in the same test tube with combination enzymes
The DNA molecules are chopped into numerous fragments, separated by molecular weight, then combined into one long sequence
The DNA molecules are mixed in a test tube, and their successful union is signaled by a change in the color of the solution

Which is not a danger associated with somatic-cell gene therapy?
Therapeutic genes may be inserted into the middle of another gene, disrupting its function
Genes may not produce any protein, even if appropriate regulatory sections are included
Inserted genes may have profound effects on the genomes of the subject's children
Inserted genes may have cancer-causing effects

Why are concerns about the individuality of clones scientifically questionable?
Identical twins have very different personalities, and they are essentially clones of each other
Clones of plants are made all the time when gardeners grow new plants from cuttings
The environment and not the genes is the major shaper of the personality
No clone would ever want to be exactly the same as his parent

Which is most closely associated with the process of sexual selection?
The evolution of mimicry by walking sticks and other insects
The extravagant feathers of a male peacock
Apparently altruistic acts between siblings
A desire on the part of males to mate with their sisters

Which best describes the theory of punctuated equilibrium?
It postulates slow evolution that due to geological processes does not appear in the fossil record
It states that species tend to remain stable but individuals vary a great deal
It states that species generally remain stable but this stasis is occasionally interrupted by rapid evolutionary change
It argues that random genetic changes are more important than natural selection in speciation

Which is not an apparent paradox resolved by replicator theory?
The existence of untranscribed DNA
The existence of altruism between siblings
The existence of sexual reproduction
The existence of bacterial cells