BackAdaptive radiations can be a direct consequence of three of the following four factors. Select the exception:
a. Vacant ecological niches
b. Genetic drift
c. Colonization of an isolated region that contains suitable habitat and few competitor species
d. Evolutionary innovation
Ancient photosynthetic prokaryotes were very important in the history of life because they
a. Produced the oxygen in the atmosphere.
b. Are the oldest-known archaea.
c. Were the first multicellular organisms.
d. Showed that life could evolve around deep-sea vents.
Which of the following groups of amino acid residues would likely be found in the portion that crosses the lipid bilayer?
a. Acidic
b. Basic
c. Polar uncharged
d. Nonpolar
Which of the following steps has not yet been accomplished by scientists studying the origin of life?
a. Synthesis of small RNA polymers by ribozymes
b. Formation of molecular aggregates with selectively permeable membranes
c. Formation of protocells that use DNA to direct the polymerization of amino acids
d. Abiotic synthesis of organic molecules
The animals and plants of India are very different from the species in nearby Southeast Asia. Why might this be true?
a. India was once covered by oceans and Asia was not.
b. India is in the process of separating from the rest of Asia.
c. Life in India was wiped out by ancient volcanic eruptions.
d. India was a separate continent until about 45 million years ago.
Adaptive radiations may be promoted by all of the following except one. Which one?
a. Mass extinctions that result in vacant ecological niches
b. Colonization of an isolated region with few competitors
c. A gradual change in climate
d. A novel adaptation
Consider the endosymbiosis theory for the origin of the mitochondrion. How did each endosymbiotic partner benefit from the relationship?
Draw and label the plasma membrane of a cell that is placed in a solution with concentrations of calcium ions and lactose that are greater than those on the inside of the cell. Use arrows to show the relevant gradients and the activity of the following membrane proteins:
(1) A pump that exports protons
(2) A calcium channel
(3) A lactose carrier
Most of the proteins that enter the nucleus possess a nuclear localization signal (NLS), even if they are small enough to pass through the nuclear pore complex unhindered. Why would a small protein have an NLS, when it naturally diffuses across the nuclear pore complex without one?
Fossilization continues even today. If you wanted to increase the probability that your deceased favorite pet would become fossilized, what actions would you take?
a. Place the corpse in an environment where decomposition is rapid (such as a forest).
b. Place the corpse in an environment where decomposition is slow (such as a swamp or bog).
c. Place the corpse in an environment where there are plenty of rocks (such as a boulder field).
d. Place the corpse in an environment where plenty of oxygen is available (such as in a mountain stream).
Why was finding a close relationship between mitochondrial DNA and bacterial DNA considered particularly strong evidence in favor of the endosymbiosis theory?
In the late 1700s, machines that could blast through rock to build roads and railways were invented, exposing deep layers of rocks. How would you expect this development to aid the science of paleontology?
Coral reefs are biodiverse ecosystems that provide food, income, coastal protection, and many other services to millions of people. Yet coral reefs are under threat from human impacts such as climate change—many corals cannot tolerate the warming ocean water and have suffered massive 'bleaching' events, which can be fatal. Researchers have discovered that some corals have the capacity to acclimatize to warmer water, while other corals do not. The researchers fear that because corals are long-lived colonial animals and thus evolve slowly, they may not be able to adapt to global warming fast enough to avoid extinction. Explain how the difference between acclimatize and adapt is important to the fate of corals.