1. Diversity labs:
(2m) Name one feature that is characteristic of and unique to members of each of the kingdoms represented by organisms A and B.
2. Natural selection:
(6m) To farmers, yield - the biomass that can be harvested from a plot of land - is a very important trait of crops. Yield is a multigene trait, but can be improved by continuous selection in many crop plants. Table A shows corn yield data (in tonnes/ha) from an experimental plot.
a. Calculate the selection differential for a plant breeder who selects plants yielding 15 or more tonnes/ha.
b. Explain why the plants artificially selected for increased reproductive capacity will not necessarily show increased survival ability.
3. Natural selection:
(6m) The lobster is a well-known ocean dwelling crustacean which is especially popular in fine seafood restaurants. The carapace length of a lobster at reproduction (a measure of body size) is determined solely by environmental conditions, and ranges from 4 to 12 cm. The minimum carapace length a lobster must have to be captured by a lobster fisher (and end up on your dinner plate) is 9 cm.
Figure A shows the relationship between carapace length and number of eggs. Given the above information:
a. What is the optimum carapace length at reproduction for a female lobster? Briefly explain.
b. Would you expect natural selection to act on carapace length in lobsters? Why or why not?
c. Assume that you took a sample of lobster larvae from the population before humans ever thought of eating them, grew them to maturity and measured their carapace length. After four decades of intensive fishing, you repeated the exercise. Would you expect the second sample to show an increase, a decrease or no change in mean carapace length? Explain your answer.
4. Life divides and conquers the land:
(7m) Examine the fungus Rhizopus.
a. Draw and label three fungal structures visible on this fungus.
b. Identify the ploidy of each structure.
c. Clearly indicate any sexual and/or reproductive structures seen on this fungus, by labelling such structures as S (sexual), R (reproductive) or SR (both).
5. Genes and inheritance:
The card contains a family tree showing the inheritance of an inherited skin disorder. This disorder is affected by a single gene, with two alleles showing a simple dominant-recessive relationship. The woman indicated with an asterisk(*) marries a male affected with this disorder.
(1m) a. Which allele is dominant?
(1m) b. What is the woman's genotype?
(3m) c. What is the chance that the first child born to this couple will be affected? Show how you derived your answer.
6. Life divides and conquers the land:
Observe the specimen, figure and slide of Psilotum nudum, the whisk fern.
(1m) a. Name one structural adaptation for terrestrial life present in this plant.
(1m) b. Name one characteristic of this plant that restricts it to periodically moist environments.
(1m) c. Name one feature that this plant is thought to share with the first vascular plants.
(1m) d. Name one feature that suggests that this plant is a secondarily reduced fern.
7. Earth comes alive & Genes and inheritance:
(5m) Gregor Mendel performed his genetic experiments on peas. He might have obtained different results if he had studied another organism.
a. State each of Mendel's Laws of Inheritance.
b. Clearly state why each law would be violated in bacterial reproduction.
8. Design of organisms:
(5m) Consider the two femurs at this station.
a. Determine the k value for each femur.
In marrow-filled mammalian long bones, a bone of a given strength with k = 0.63 should have a minimum mass per unit length.
b. Femur B has a k value very different from 0.63. Explain why natural selection might have favored such a k value in this animal.
9. Earth comes alive:
(3m) Living protists show tremendous diversity of cellular structure. Almost all protists are aerobic, with respiration taking place within mitochondria, but a few unusual protists lack mitochondria. A number of groups of protists are photosynthetic, with photosynthesis taking place within chloroplasts. All photosynthetic protists contain mitochondria. Chloroplasts and mitochondria are thought to have arisen by an endosymbiotic association of originally free-living cells. Based on the information given above, suggest a likely evolutionary sequence for the endosymbiotic associations leading to a modern photosynthetic protist.
10. Life divides and conquers the land:
Consider plants A, B, C and D and Figure E, showing a phylogenetic tree for the Kingdom Plantae.
(2m) a. Fill in spaces 1, 2, 3 and 4 at the top of this phylogenetic tree with the names or letters of plants A, B, C and D.
(2m) b. i. Name a possible ancestral group to all four plants, shown as space 5 in Figure E.
ii. Give one piece of evidence supporting this group as ancestral to plants.
(3m) c. Name the important features, labelled as 6, 7 and 8 on the phylogenetic tree, that developed in the evolution of these organisms and allowed for adaptive radiations of these groups.
(1m) d. What is the ploidy of plants A, B, C and D?
11. Genes and inheritance:
The card contains a family tree showing the inheritance of curly tails in dogs. In this imaginary example, tail form in dogs is determined by a single gene, with two alleles (curly and straight) showing a simple dominant-recessive relationship.
(1m) a. Which allele is dominant?
(1m) b. What is the genotype of the dog indicated with an asterisk(*)?
(3m) c. The dog indicated with an asterisk(*) is mated to a curly-tailed dog. What phenotypes would you expect to see in the resulting litter, and in what ratio? Show how you derived your answer.
12. Earth comes alive:
Early in the history of life on earth, photosynthesis evolved in cells similar to modern cyanobacteria. O2 is produced as a byproduct of this process.
(2m) a. Briefly explain how O2 is formed in photosynthesis.
The production and accumulation of O2 dramatically transformed the earth and offered new dangers and opportunities to organisms.
(1m) b. Briefly explain why O2 was dangerous to organisms on the early earth.
(1m) c. How did the availability of O2 lead to an increase in the energy available to living organisms?
13. Genes and inheritance:
(2m) a. Name two events during meiosis that lead to variability in the products of meiosis.
(2m) b. List any gametes that could be produced by the meiotic division of cell with the genotype AABBccDD.
14. Life divides and conquers the land:
(4m) Suppose that you are walking through the forest with a friend and you find Plants C and D on the forest floor. You point them out and say "These belong to the same species." Your friend replies "I know enough about biology to know that members of the same species should look more similar than these two." How would you explain your statement to your friend?
15. Design of organisms:
(3m) Explain, using the principles of scaling, why an ant can carry objects heavier than itself while an African elephant cannot.
16. Natural selection:
(5m) Ten nuts are on display at this station. Of these ten nuts, only the three marked with a white "X" later successfully germinated. Calculate the selection differential on nut weight from this episode of selection. Show your calculations.
17. Earth comes alive:
(3m) Cyanobacteria - formerly called blue-green algae - are photosynthetic members of the Domain Bacteria.
a. Why are cyanobacteria classified as members of the Domain Bacteria?
b. What is the proposed role of ancestral cyanobacteria in the evolutionary history of plants?
18. Design of organisms:
(3m) In frogs, venous (low O2) and arterial (high O2) blood mix somewhat in the heart, as shown in Figure B. Why is this design feature (blood mixing in the heart) poor in terms of oxygenation efficiency at the lungs?
19. Design of organisms & Legacy of the past:
(5m) In vertebrate evolution, there has been a reduction in the number of aortic arches - large arteries carrying blood from the heart to the body tissues - in the evolutionary lines leading to birds and mammals. In birds, the aorta loops up and travels down the right side of the body. In mammals, it's on the left.
a. On the phylogenetic tree, place birds (B), mammals (M) and some common ancestor (A) which had multiple aortic arches.
b. With an arrow or arrows, indicate where the modification from multiple arches to one arch occurred.
20. Forest walk (Life divides and conquers the land):
(2m) a. A new bacterial species, Liveson salmonberrius, has been identified. This previously undescribed species infects salmonberry flowers and can rapidly devastate salmonberry patches.
What changes might the arrival of Liveson salmonberrius select for in salmonberry's relative energy allocation to flowers and runners? Explain your answer.
b. A forest area is clearcut to make way for new construction. Financing of the new construction falls through, and the now naked land is left that way.
(2m) i. Name one plant species (other than red alder) that you might expect to be an early pioneer in the re-growth on this land. Give one reason why this plant is a successful pioneer species.
(1m) ii. Name the term that ecologists use to describe the change that would be expected over time as the forest community re-grows.
(4m) c. Name one organism at each of four trophic levels. Wherever possible, use organisms that you saw on your forest walk.