21. Evolution

Contrast the structure of glycogen and chitin in terms of their monosaccharides, glycosidic linkages, and interactions between polysaccharide chains.

Consider the reaction between carbon dioxide and water to form carbonic acid: CO2(g)+H2O(l)⇌CH2O3(aq) In the ocean, carbonic acid immediately dissociates to form a proton and bicarbonate ion, as follows: CH2O3(aq)+H+(aq)⇌CHO3−(aq) If an underwater volcano bubbled additional CO2 into the ocean, would this sequence of reactions be driven to the left or the right? How would this affect the pH of the ocean?

Since the modern synthesis, the technical definition of evolution is a change in allele frequency in a population over the course of generations.

a. Traits, species

b. Allele frequency, population

c. Natural selection, natural environment

d. Adaptations, single organism

e. Fitness, population

Even though marsupial mammals give birth to live young, an eggshell forms briefly early in their development. This is evidence that:

a. Marsupials share a common ancestor with some egg-laying species

b. Marsupials are not really mammals

c. All animals arose from a common ancestor.

d. Marsupial mammals were separately created by God

e. The fossil record of marsupial mammals is incorrect

Lysozyme, an enzyme found in human saliva, tears, and other secretions, catalyzes the hydrolysis of the β-1,4-glycosidic linkages in peptidoglycan. Predict the effect of this enzyme on bacteria and how it may be involved in human health.

Within a few weeks of treatment with the drug 3TC, a patient's HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained?

a. HIV can change its surface proteins and resist vaccines.

b. The patient must have become reinfected with a resistant virus.

c. A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.

d. HIV began making drug-resistant versions of its enzymes in response to the drug.

Evaluate this statement: Evolution is said to occur when new traits accumulate over time, increasing complexity.

Galactosemia is a potentially fatal disease that occurs in humans who lack the enzyme that converts galactose to glucose. If you were a physician treating a person with this disease, which of the following would you have them exclude from their diet?

a. Maltose

b. Starch

c. Mannose

d. Lactose

The similarity in skin color among different human populations appears to be primarily the result of:

a. Natural selection

b. Convergent evolution

c. Which biological race they belong to

d. A and B are correct

e. A, B, and C are correct

When H₂ and CO₂ react, acetic acid can be formed spontaneously while the production of formaldehyde requires an input of energy. Which of these conclusions can be drawn from this observation?

a. More heat is released when formaldehyde is produced compared to the production of acetic acid.

b. Compared to the reactants that it is formed from, formaldehyde has more potential energy than does acetic acid.

c. Entropy decreases when acetic acid is produced and increases when formaldehyde is produced.

d. Only acetic acid could be produced under conditions that existed in early Earth.

Which of the following taxonomic levels contains organisms that share the most recent common ancestor?

a. Family

b. Order

c. Phylum

d. Genus

e. Class

The geneticist James Crow wrote that successful scientific theories have the following characteristics: (1) They explain otherwise puzzling observations; (2) they provide connections between otherwise disparate observations; (3) they make predictions that can be tested; and (4) they are heuristic, meaning that they open up new avenues of theory and experimentation. Crow added two other elements of scientific theories that he considered important on a personal, emotional level: (5) They should be elegant, in the sense of being simple and powerful; and (6) they should have an element of surprise. How well does the theory of evolution by natural selection fulfill these six criteria?

From what you have learned about water, why do coastal regions tend to have milder climates with cooler summers and warmer winters than do inland areas at the same latitude?