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Evolutionary Biology CH. 1 End of Book Questions

Terms in this set (17)

Define biological evolution.

a. Any process by which populations of organisms change over time.
b. Any change in the inherited traits of a population that occurs from one generation to the next.
c. Change within a lineage due to natural selection and other mechanisms.
d. All of the above
d. All of the above
What type of evidence has been used to infer that whales evolved from mammals that used to live on land (rather than from fishes, for example)?

a. Whales share traits with other mammals, like needing to breathe air and giving birth to live young that feed on milk.
b. Whales still have developmental genes for traits they no longer have, like hind legs.
c. Fossils of early whales display combinations of traits that reveal a gradual transition from terrestrial to aquatic life.
d. All of the above.
d. All of the above.
Why do baleen whales still have genes for building teeth?

a. These genes are now used to make baleen.
b. Their ancestors had teeth, and they inherited these genes from them, even though the genes no longer function.
c. Their descendants might need teeth, so evolution keeps the genes around.
d. Evolution can't take away genes, only add new ones.
b. Their ancestors had teeth, and they inherited these genes from them, even though the genes no longer function.
What makes hemagglutinin important in the evolution of influenza viruses?

a. It allows a virus to attack the red blood cells of its host.
b. It is the basic building block of virus cell walls.
c. It allows the virus to bind to the cells of its host.
d. All of the above.
c. It allows the virus to bind to the cells of its host.

Hemagglutinin:
- Influenza viruses have proteins called hemagglutinins on their surfaces that allow the viruses to bind to the receptors naturally present on epithelial cells in the host's respiratory tract
- After binding to the receptors, the viruses trigger the cells to open a passageway into the cell, through which the viruses enter
Which of the following is a true statement?

a. The ancestors of whales needed more food than could be found on land, so they evolved features that allowed them to survive in the water.
b. Whales and humans share a common ancestor.
c. Mutations always cause the improvement of a trait.
d. Viruses mutate because they want to have the best-adapted hemagglutinins throughout their evolution.
b. Whales and humans share a common ancestor.
Which of the following is not a place that scientists look for evidence of evolution?

a. The fossil remains of extinct animals.
b. Comparison of homologous traits in various species.
c. Change during an individual organism's lifetime.
d. Change across generations in wild populations.
c. Change during an individual organism's lifetime.
Which of these statements about phenotypes is true?

a. Individuals that adjust their phenotypes in response to their environment cannot be favored by natural selection.
b. Natural selection does not act on phenotypes.
c. An individual's behavior is not part of its phenotype.
d. An individual's phenotype is a result of its genes and the environment in which it develops.
d. An individual's phenotype is a result of its genes and the environment in which it develops.

Phenotype:
- A phenotype is a measurable aspect of organisms, such as morphology (structure), physiology, and behavior
- Genes interact with other genes and with the environment during the development of the phenotype
Why do scientists overwhelmingly accept the theory of evolution?

a. Because the theory has overwhelming evidentiary support.
b. Because the theory explains and predicts independent lines of evidence.
c. Because scientists have tested and retested its predictions.
d. All of the above.
d. All of the above.
Which of the following best describes natural selection?

a. Natural selection is a mechanism that allows individuals to pass on to their offspring those traits that are favorable.
b. Natural selection occurs when heritable characteristics cause some individuals to survive and reproduce more successfully than others.
c. Natural selection is a mechanism that allows for greater reproductive success in all species within a given environment.
d. All of the above.
b. Natural selection occurs when heritable characteristics cause some individuals to survive and reproduce more successfully than others.
Why is influenza a worldwide threat?

a. Because influenza has the potential to kill millions of people from a single outbreak.
b. Because mutations in the influenza virus can allow the virus to evade the human immune system.
c. Because viral reassortment can result in the flu crossing over from another species to humans.
d. All of the above.
d. All of the above.
In the figure below, what do the arrows above the host cell represent?
Description: Arrows are drawn from the cell to five viruses of which four are identical to the host cell and one is mutated.

a. Transfer of surface proteins from one virus to the next.
b. Movement of viruses from one host to the next.
c. Reassortment of virus genes from one time point to the next.
d. Copies/daughter viruses produced by each virus from one generation to the next.
d. Copies/daughter viruses produced by each virus from one generation to the next.
Recall the quotation from Theodosius Dobzhansky: "Nothing in biology makes sense except in the light of evolution." Give one example of how evolutionary principles help us "make sense" of biological observations.
- Scientists understand that biological evolution is simply the processes by which populations of organisms change over time, and variation among individuals is the fundamental reason for that change.

- If some individuals survive better or produce more offspring because they vary genetically from other individuals, and they can pass those traits to their offspring, then offspring with those traits will have a better chance of surviving and reproducing than individuals without them.

- In time, those traits will be more common in the population. Scientists have observed these phenomena over and over, in nature and in their laboratories.

- These evolutionary principles explain biological observations as diverse as the streamlined bodies of fishes and whales, the massive horns on beetles and antlers on elk, and why humans see one range of colors whereas other animals see other ranges, for example.
What kinds of evidence do evolutionary biologists use to test hypotheses about how different species are related to each other?
- Evolutionary biologists consider observations of living species, DNA, and fossils

- Scientists make comparisons between living species and fossils of extinct species to study shared anatomical traits. More recently, they have begun comparing DNA.

- Close relatives will share more traits, both physical and genetic, inherited from their common ancestor.

- So scientists can develop hypotheses for how these traits changed over time and how they evolved between different lineages and test them with additional evidence.
What are some characteristics that distinguish whales from sharks and tunas?
Although whales have fishlike bodies, with the same sleek curves and tails you can find on tunas and sharks, they have a number of distinguishing characters.

- Whales do not have gills, so they cannot extract dissolved oxygen from the water in which they live. Whales must rise to the surface of the ocean in order to breathe.

- Whales and dolphins have long muscles that run the length of their bodies — much like the long muscles running down your back — whereas tuna have muscles that form vertical blocks from head to tail.

- Whales lift and lower their tails to generate thrust. Sharks and tunas move their tails from side to side.

- And whales give birth to live young that cannot get their own food; instead, the young must drink milk produced by their mothers. Only some species of sharks and fishes give birth to live young, but those offspring can feed themselves; sharks and tuna do not produce milk.

So despite their fishlike appearance, whales are very different from sharks and tuna.
How do mutations become more or less common in a population over the course of generations?
Mutations may be detrimental (or even lethal); they may be harmless; or they may be beneficial in some way.

- Detrimental mutations should become less common over the course of generations because individuals with those mutations shouldn't do very well relative to other individuals.

- If a mutation is beneficial, however — one that helps an organism fight off diseases, thrive in its environment, or improve its ability to find mates, for example — that individual should produce more offspring on average than individuals without the mutation.

- Mutations can also become more or less common in a population due to chance, a process called genetic drift.
Genetic drift: evolution arising from random changes in the genetic composition of a population from one generation to the next.
What role does viral reassortment play in flu pandemics?
- When two viral strains infect the same cell, their genetic material can become mixed as copies of their RNA are bundled into new virus particles.

- The new combinations of genetic material can give rise to new beneficial characteristics of the virus, for example, characteristics that permit bird flus to invade human cells.

- Humans who have never been exposed to the characteristics of bird flus may have no antibodies to fight the infection, and the virus can reproduce rapidly.

- A bird flu virus that gains the capacity to spread from human to human through reassortment may spread rapidly over large geographic areas, leading to a serious pandemic
Explain how phylogeny helps us understand the evolutionary history of populations, genes, and species.
The simplest answer is that phylogenies can relate the entire evolutionary history of a species in a single image.

- From this image, one can infer the myriad genetic changes that had to occur for related species to branch off from one another and form new populations of species.
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