Option+D

1. Murchison meteorite contains more alpha-aminoisobutyric acid/valine/proline/pipecolic acid; Murchison meteorite contains less alphaNbutyric acid/N-ethylglycine/sarcosine; Murchison meteorite contains same amount of glycine/alanine/norvaline/isovaline/aspartic acid; the same amino acids are found on both/similar quantities of amino acids;
 * pg. 291**

2. Meteorites could have been the source of organic molecules necessary for the start of life on earth/panspermia;

1. Yellow snails are more commonly eaten early in the experiment/banded snails less commonly eaten; number of yellow snails eaten declines significantly after the second day; number of banded snails eaten increases (significantly) after day 10/when number of yellow snails eaten declinse to (almost) zero;
 * pg. 293**

2. Number of yellow snails available for eating declined significantly; Yellow snails had better camoflauge as the experiment progressed/banded snails easier to see when background turned yellow;

3. Insufficient evidence to know conclusively; may be ecologically isolated because adult forms could be more heavily predated at different times; if the brown to green habitat switch is an annual/seasonal event; told that they are the same species so by definition of species, they interbreed;

4. balanced polymorphisms is when natural selection confers a survival advantage on two or more alleles in a population; banded snails are selected when vegetation is brown **and** yellow snails are selected for when vegetation is green;

**p. 296 DBQ: convergent evolution** NB: there appears to be a typo: lulidochromis and julidochromis are presumably the same. Also, have students note that Figure 8 departs from the convention of capitalizing and italicizing genus names.

1. Convergent evolution: any of the pairs in the same “row” of Part A but from different lakes, e.g., lulidochromis and melanchromis have long stripes, and they evolved in different lakes.. Divergent evolution: any of the pairs at the final branches of the phylogenetic tree, e.g. cyrtocara and placidochromis. Divergent evolution implies relatively recent branching of the phylogenetic tree (if you go back far enough, every pair of species can be regarded as divergent, since all share a common ancestor at some point). 2. Bathybates is similar in appearance to Rhamphochromis, and so it is possible that the convergent evolution which produced the similar appearance also led to similar feeding behaviors. “form follows function.” 3. Lake Tanganikya, since there are larger differences in the mitochondrial DNA among the fish there, implying a longer period of evolution (due to the mitochondrial clock ticking at a regular rate). 4. Any of the following (?): Camouflage/blend in with aquatic vegetation/attract mate as part of sexual selection

1. (22+9+8+7+13)% = 59% 2. Beetles are 22% of all species; if all species were created by God, He must have really liked to have lots of beetles around. 3. The evolution of angiosperms created a large diversity of habitats and foods for beetles to form new species.
 * p. 296 DBQ: adaptive radiation of beetles**


 * pg. 299** - Data-based questions:

Minor change made with 1a. Substantive changes were made with 1.c, 2, and 3. I hesitate to delete the original answer on my own, and so I leave the original here for easier comparison. If another reader agrees with me, please delete this message and the original, leaving (or improving upon) my changes, but if you disagree, kindly let me know. Thanks, bill.watkins@aya.yale.edu] 1. a) cytochrome C is the same in all 3 mammals 1. b) Ancestors of sheep diverged more recently from cows; as their fewer number of base substitutions signifying more closely related molecular compositions. 1. c) By using the percentage base substitutions as a molecular clock it can be deduced that pigs diverged from the tree before sheep, because pigs have more mutations. [***Originally: c) By using the percentage base substitutions as a molecular clock it can be deduced that pigs diverged later from sheep as they have more mutations.]**
 * 2. Researchers would compare morphology (anatomical differences), protein structure, genomes, and physiological and metabolic processes, in both modern and, as much as possible using fossilized remains, ancient species. Information from a variety of sources is used to generate a phylogenetic tree which best fits the data. “A time-scale” and “common ancestor” are not good answers for this question; they can only be inferred from the evidence. **
 * [ ****Original: 2. Morphology, Physiology and comparing genomes would assist in creating a more accurate phylogenetic tree.**
 * 3. This question can be discussed in two ways, depending on whether morphology refers to the organism as a whole, or merely to the shape of the beta protein. **
 * Morphology refers to the physical structure and/or form of organisms (as opposed to physiology, which focuses on the function of these structures). Even a child, asked to rank animals based on their physical similarity to humans, would list them as chimp, gorilla, rhesus monkey, dog, horse, chicken and frog. The fact that the number of differences in the beta chain of hemoglobin produces the same ranking shows that the microscopically-small differences in amino acid sequence correlates very highly with the visible-to-the-naked-eye differences in morphology/shape. **
 * With regard to the morphology of the beta protein, the differences in amino acid sequences probably do not result in major changes in the shape of the protein, since all species have functioning hemoglobin molecules. However, what changes in shape there are would presumably be correlated with the number of differences. **
 * [ *** Original: 3. If differences are found in the genomes of organisms this could result in differences in morphology. Differences in proteins or smaller molecules may not show significant morphological changes.]


 * pg. 300** - Data-based questions: dating fossils using radioisotopes

1. a) 1/4 = 25% b) 1/16 = 6.25%

2. Approximately 1.5 half-lives, 35-40% remaining

3. Cannot use K as it has a half life that is too big. A sufficient amount of atoms would not have decayed to use for dating methods.

4. a) Carbon 14 would be accurate b) It has a short half life of 5,700 years.

p. 302, Cranial capacity and diet 1.a. There is a high correlation, and modern humans and most of their ancesters are close to the curve; only two species, P. bosei and modern chimpanzees do not fall close to the curve. 1.b. There probably was a “virtuous cycle” where the larger brain capacity permitted the communication/language/memory/social relationships which facilitated better hunting/gathering/preparation/cooking/fermenting/storage of food, which meant that those with a genetic potential for larger brain growth received the necessary nutrients, which meant that brains got bigger, etc. 2.a. change in teeth; change in jaw bones and muscles; presence of animal bones close to human bones; human tooth marks or human-made cutting marks on animal bones. 2. b. Protein in meat can be used for energy, but its fat contains more energy (although wild animals tend to be lean). The nutritional improvement from eating meat therefore is probably primarily due to its providing essential amino acids, vitamins and highly bioavailable minerals. These nutrients could allow for further brain growth and both biological and cultural evolution: the development of language/bipedalism/manual dexterity/social interactions, etc. 3.a. There is a positive correlation between dietary quality and brain size, (but humans have a larger brain than would be expected from its dietary quality.) 3.b. Short answer: Humans have branched off, forming a new species and taking advantage of the resources, such as a more diverse diet, in a different niche. Longer answer: Figure 19 suggests that dietary quality is not the only factor explaining brain size, since humans are so far off the curve. We don’t know how the dietary quality index is calculated, but presumably it takes into account the greater variety in the human diet. One possible reason is that the rapid brain growth, which starts in gestation, starts to level off after birth in chimps, but continues in humans (see Biozone, The Development of Intelligence.”) Human infants are far more dependent on caregivers than other animals, giving a survival advantage to individuals in families with good caregiving skills. Infants born into such families would receive better nutrition, allowing greater growth, and be more likely to pass on these cultural traits to their offspring, allowing their offspring to grow larger brains. (Other explanations possible, e.g., increased consumption of essential fatty acids found in seafood.)