Objective 2:
1. amino acids, simple sugars, alcohols, and fatty acids
2. Although it did not prove Oparin’s theory (experimental evidence may support, not prove), it did support Oparin’s theory, and thus, increase the confidence of the scientific community in the reasonableness of Oparin’s theory.

Objective 5:
1. No—The evolution of life on earth is a one-time event. Since we haven’t developed a time machine, the best that scientist can do is speculate on the probability of certain events currying.
2. Organelles to primitive cells
3. As primitive cells depleted organic molecules that had formed on primitive earth, life may have been curtailed if photosynthesis had no evolved. This process resulted in adding oxygen to the earth’s atmosphere. This was actually thought to be harmful to most forms of life at that time. However, the life forms that were able to use the oxygen to derive a greater amount of energy from glucose had an advantage.
4. Yes. Actually dehydration was critical in concentrating the early protein molecules.
5. All processes are either mentioned directly or implied in the chart.

Objective 6:
1. presence of microbes that decompose organic matter
2. presence of oxygen in atmosphere that would oxidize molecules
3. energy that was available on primitive earth is no longer available
1. elements found in living systems are available
2. specialized habitats may contain energy, for example around the hot vents on ocean floor
3. time available

Objective 9:
Darwin attributed the evolution of life on earth to natural selection whereas Lamarck explained evolution on the basis of the inheritance of acquired characteristics.

Objective 11:
adaptation—g, deme—i,  evolution—k, gene flow—a,  gene frequency—c, gene pool—m, genetic drift—d, mutation—h, natural selection—n,  niche—f, nonrandom mating—j,  population—l, random mating—e, species—b

Objective 14:
1. It is via mutation that new genetic material is introduced to the gene pool.
2. Point mutation—a change in the base sequence due to inversion, deletions, substitutions, or additions. Chromosomal mutation - gross changes in chromosomes such as chromosomal breakage or changes is the chromosome number (nondisjunction, for example, can cause changes in the chromosome number).
3. Gamete
4. This is how new genetic material gets added to the gene pool.
5. No. Most do not since they are harmful.

Objective 15:
Situation A: Disruptive because the two extreme phenotypes are favored.
Situation B: Stabilizing because the two extreme phenotypes are selected against.
Situation C: Directional because one of the extreme phenotypes is selected against.
the example illustrates directional selection pressure.

Objective 16:
a) birds; dark morph or form because the trunks of trees would be dark due to lake of
lichens.
b) because they are not as likely to have the disease malaria and the trait is not harmful to the individual under usual circumstances. In malaria infested areas normal individuals (homozygous for the normal allele) are more likely to suffer from malaria.

Hb^AHb^S

Because Hb^AHb^S individuals have a selective advantage in this environment.

Objective 18:
Arctic fox—it has the least amount of surface area since heat is lost through surface
no because a long tail would increase surface area and hence increase the amount  of heat lost
the large ears of the fennec are a cooling device
those without tails would tolerate lower temperatures, their bodies are more compact and hence do not lose as much heat by radiation.
Extremities become shorter and the body more compact as the average temperature of the habitat decreases.

Objective 19:
#1: prezygotic; copulation between these closely-related species will not take place
#2: postzygotic; mules are sterile hybrids
#3: prezygotic; copulation between these closely-related species will not take place
#4: postzygotic; the two types of cotton plants are members of the same species
#5: prezygotic; copulation between these closely-related species will not take place
#6: prezygotic; copulation between these closely-related species will not take place

Objective 20:
See pp. 320 - 325 in your text. You are not responsible for stasipatric speciation. It is not discussed in your text. You should focus on the idea that allopatric speciation is the major mechanism for the formation of a new species.

Objective 22
#1: a variety of both physiological and morphological adaptations are responsible for the ability of homeotherms (warm blooded organisms) to maintain a relatively constant body temperature. You will study some of the mechanisms in Biology 102. Some obvious morphological features that organisms use  are fur and  fat to conserve body heat. Sweat glands allow organisms to use evaporative cooling to get rid of excess heat. Homeotherms need more fuel (carbohydrates, fat) to burn (remember in cellular respiration as molecules are oxidized to generate ATP a significant amount of the energy winds up in the form of heat) to elevate body temperature.  The final question in this series is not a very good question! Evolution is a reflection of changes in gene frequencies   in the population.
#2: all
They "think" they are a twig!
No—otherwise, the organisms would be 100% successful in escaping perdition.

Objective 23:
Adaptive radiation reflects speciation. A significant amount of biological diversity is due to adaptive radiation.

Objective 24:
Ability to move about - limbs, body short and stout as opposed to streamlined
Gas exchange - invaginated respiratory system to keep respiratory membranes moist.
Reproduction - internal fertilization, amniotic egg
Sensory changes - visual clues assume greater importance
Food getting - must move through environment to obtain food

Home   eerdahl@nvcc.edu
Emma Erdahl, Associate Professor of Biology
Northern Virginia Community College
Last revised: 08/19/2002