Principles of Evolution - Chapter One

What are some characters that distinguish whales from sharks and tuna?

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, they 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. They lift and lower their tails to generate thrust. And whales give birth to living young that can not get their own food; instead, the young must drink milk produced by their mothers.

Define biological evolution and pose 3 questions evolution can potentially address.

Biological evolution is any change in the inherited traits of populations that occur from one generation to the next. Questions vary.

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.

How do mutations become more or less common in a population over the course of generations?

It depends on whether or not the mutation is beneficial or detrimental. Or mutations can also become more or less common in a population due to chance, a process called genetic drift.

Reread the quote from Theodosius Dobzhansky at the start of the chapter, and give one example of how evolutionary principles help us "make sense" of biological observations. "Seen in the light of evolution, biology is, perhaps, intellectually the most satisfying and inspiring science," "Without that light it becomes a pile of sundry facts- some of them interesting or curious but making no meaningful picture as a whole."

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. Those traits will be more common in the population. These evolutionary principles explain biological observations.

Using evidence from fossil whales, demonstrate how lineages can change through time.

The fossil record found for whales leads back to Ambulocotus, a whale fossil who had legs, proving that whales and dolphins had evolved from a terrestrial ancestor. Another example of change through time could be the fact that whales have hip bones with no actual function anymore.

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 can give rise to new beneficial characteristics of the virus. Humans who haven't been exposed to the new characteristics of bird flus may have no antibodies to fight the infection. A bird flu that gains the capacity to spread from human to human may spread rapidly over large geographic areas, leading to a serious pandemic.

Explain why Theodosius Dobzhansky said that "nothing in biology makes sense except in the light of evolution." a. He was an atheist. b. He was fascinated by the capacity for evolution to explain the diversity of life and its universal biological similarities. c. He wanted to explain the origin of life. d. All of the above. e. None of the above.

b. He was fascinated by the capacity for evolution to explain the diversity of life and its universal biological similarities.

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 cant take away genes, only add new ones. e. All of the above. d. None of the above.

b. Their ancestors had teeth and they inherited these genes from them, even though the genes no longer function.

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. e. All of the above are true statements. f. None of the above is a true statement.

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 in populations in the wild. e. None of the above (scientists look to all of these sources).

c. Change during an individual organism's lifetime.

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 a virus cell walls. c. It allows the virus to bind to the cells of its host. d. All of the above are true. e. Hemagglutinin is not important to viruses.

c. It allows the virus to bind to the cells of its host.

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 are possible definitions. e. None of the above is an appropriate definition.

d. All of the above are possible definitions.

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 genotype. e. Most phenotypes are perfectly adapted to their environments.

d. An individual's behavior is not part of its 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. Because a scientific theory is a comprehensive explanation of many diverse observations. e. All of the above.

e. All of the above.

Identify characteristics of viruses that make them difficult to control.

mutations, reassortment, ability to "mix" with other strains of virus.