Answers are in BOLD, BLUE font (NOTE: Answers for questions that ask for examples have a few of the possible answers that are acceptable - there may be other correct answers)
Instructions: This review is worth 100 points (10% of your course grade) and will be due in class Wednesday, 4/13/05. No exceptions and late reviews will result in at least a 5% deduction. You may not consult any references or any other person while working on this review. Your signature at the bottom of the last page signifies that the work is yours alone and is pledged under the Honor Code. When you break the seal on the envelope you will have three hours to complete the review! Please print legibly; I can only grade what I can read! For each question or part to a question, limit your answers to the space below each question, unless otherwise specified. Any part of your answer outside of the space provided will not be graded.
1. Annelids and arthropods are both segmented. Yet, annelids have a closed circulatory system and insects an open circulatory system. Speculate on the adaptive value of a closed circulatory system in annelids and an open circulatory system in insects (8 points)?
Because of hydraulic skeleton, ultrafiltration in excretory system (nephron function), gas transport, and compartmentalization, closed circulatory is necessary in annelids. Their segmentation is much more complete internally than in arthropods. For insects, an open CS works well - it's not needed for gas exchange, excretory system (no filtration, only active transport), or to work with a support system.
2. Describe one feedback loop associated with hormonal control of mammalian excretion, and what this loop does to maintain blood supply to the kidneys (8 points).
Maintaining blood supply to kidneys is critical for filtering blood and maintaining proper salt balance. The key to this question is a direct link in your answer to kidney blood supply - if you only mentioned peripheral blood vessel constriction caused by ADH, you've not specifically addressed blood pressure or supply to kidneys.
Renin is secreted by the kidneys in response to low blood pressure. Rennin activates angiotensin in the blood. Angiotensin causes peripheral arterioles and efferent renal arterioles to constrict. It also causes release of aldosterone, which stimulates sodium reabsorption. The more sodium reabsorbed, the more water will follow, increasing blood volume.
ADH also plays a role. ADH is secreted by the hypothalamus, and it has a variety of effects that help the kidney function. It causes peripheral vessels to constrict and it increases permeability of collecting duct cells to water (through insertion and up-regulation of aquaporins).
3. Provide one example of how animals regulate body temperatures with blood flow (6 pts).
Dilating or constricting capillary beds or arteries that are near the surface of the skin to dissipate heat or warm the blood, respectively. Changing heart rate to move blood through the body faster or slower, in conjunction with the former, can also speed the cooling or warming of blood. Countercurrent exchange mechanisms can retain heat in the core of an animal.
4. Briefly discuss two adaptations of respiratory system that increase Q in Fick’s Law of Diffusion, one for fish and one for mammals (10 pts).
There are many options. Fish have a short distance between water flowing over gills and capillaries in the gills, they have countercurrent exchange (blood flows opposite direction of water) maximizes the length of exchange (does not maximize the concentration gradient), and they have large surface area of gills. Mammals have large surface area of alveoli, short distance that gases need to diffuse, and perfusion of capillaries around alveoli.
5. How does the endocrine system help to integrate the circulatory and respiratory systems of mammals? Provide two detailed examples (10 pts).
Epinephrine, or adrenalin secreted by adrenal gland increase both heart rate and respiratory rate during times of stress. Any hormone that is released to increase blood pressure may indirectly integrate circulatory and respiratory systems. When peripheral arterioles are constricted, systemic blood pressure rises and this could have effects on blood flow to the lungs. When glucagon is released in response to low blood glucose levels, the circulatory system transports this hormone to the liver and other tissues where complex carbohydrates are broken down. This requires oxygen from the respiratory system and requires the circulatory system to transport carbon dioxide back to the lungs.
6. How is the heart and circulatory system affected in persons with diabetes? Consider both short and long-term problems (10 points).
Because insulin decreases utilization of fat, promotes fatty acid synthesis in liver and glycerol production in adipose tissues, and inhibits release of fatty acids into blood, lack of insulin can have major effects. Excess fatty acids in blood plasma promotes liver conversion of fatty acids into phospholipids and cholesterol, which are released into blood as lipoproteins (increased up to 3x in blood in absence of insulin). High lipid concentration of cholesterol (in LDL) leads to rapid development of atherosclerosis, arteriosclerosis, and severe coronary heart disease. As fatty acid metabolism increases in liver, oxidation of fatty acids produces acetyl-CoA, which is converted to acetoacetic acid and released to blood. This can cause loss of sodium and lowered pH in the blood. Acidosis can lead to coma and death. Atherosclerosis is a buildup of fatty deposits in the smooth lining of arteries. Atherosclerosis invades superficial and deep layers of vessel walls, which narrows the lumen and decreases elasticity.
7. List the common excretory products in the table below and rank the costs of producing each, relative to each other, the amount of carbon lost per molecule of each product, and the toxicity of each relative to each other (NOTE: rank the highest in each category as 1). Then provide an example of a type of animal or animal group that secretes the product in question (8 points).
| Common Excretory Product(s) |
Relative Cost of Producing (rank 1-3) |
Relative Carbon Lost (rank 1-3) |
Relative Toxicity (rank 1-3) |
Example of Animal |
Ammonia
|
3
|
3
|
1
|
fish,
aquatic invertebrates |
Urea |
2
|
2
|
2
|
mammals
|
Uric
Acid |
1
|
1
|
3
|
insects,
birds |
8. Northern spotted owls, as you know, live in the Pacific Northwest. As the old-growth forests in which they live become fragmented by deforestation, consider their spatial structure and metapopulation dynamics. These owls will cross short stretches of open areas, but not if they’re greater than a couple hundred meters. Additionally, they will breed in second-growth forest (forest that has been logged and has regrown), but female fecundity is low and offspring mortality is high (8 pts total).
a. Describe what may happen to individual owls as the habitat is altered from a whole, connected patch to one that forces a metapopulation structure on the owls.
An individual owl may be faced with less food availability, may find it hard to find a good nest site, and may not be able to find a mate. To get full credit you had to address the situation for an individual owl.
b. Predict subpopulation growth rates (positive or negative) for each of the following patch types: IF you answered these questions without an explanation of why it would be, you might have lost some credit (if there is conditional probability involved).
i) Small old-growth forest separated from larger patch of old-growth forest by only 100 meters. Probably negative or no change - even though there's a connection to a good patch, growth of the population in the small patch will probably not increase.
ii) Very large patch of second-growth forest. Could be positive or negative depending on the size of the patch, the starting population size of owls, and the proximity to other patches.
iii) Small, isolated patch of old-growth forest. Probably negative, due to small size of patch - even if habitat is outstanding, the population cannot expand much.
9. Describe the integration of up to four (4) systems that we’ve studied and how they specifically affect other systems or are affected by other systems during food consumption. Use only one sentence for each example (>1 example can come from the same system). Each example will be worth 10 points divided by the total number of examples you use (e.g., if you choose 2 examples, they will be worth 5 points each; 4 will be worth 2.5 each).
You could have any number of examples. The number of examples you provided is divided by 10 to get the "per example" point value. There are many examples, and I'll provide a couple here. Examples only needed to show some level of integration (at least two systems, and up to four). Some examples:
During food consumption, insulin is released from the ES in response to high blood glucose levels. Insulin travels in the CS and affects fuel traffick in and from the DS.
Toxins ingested in the DS travel through the CS to the liver, where they are metabolized (hopefully) into water soluble compounds, which then travel through the CS to the ExS, where they are filtered from the blood and excreted (again, hopefully).
During food consumption, the NS sends signals that affect blood flow in the CS to maximize flow to the DS and minimize flow to peripheral systems.
10. For the following graph, answer the three associated questions, each worth 4 pts = 12 points total.
a. What are two assumptions made about this theoretical model? r and K are constant, each individual added to the population instantly affects resources, effects of additional members instantaneously affects future population growth (although from the graph it looks somewhat like discrete growth, so I accepted that), and resources are limiting (at some point).
b. What causes the model to plateau after about 18 years? Basically, resources become limiting and the population reaches environmental carrying capacity (K), which is the total number of individuals of that population that can fit in that environment or habitat.
c. If “r” is assumed to be constant in this model, how is it that growth rate declines as population size increases? By adding the term [(N-K)/K], we can adjust the growth rate of the population theoretically. In reality, r is not constant - death rates increase and birth rates decrease when population density increases and when predators become more prevalent or resources become more limiting.
11. Many natural communities are subject to disturbance of various types, from fires to predators. Describe the types of disturbances that humans cause, how this is disrupting natural populations of plants and their communities, and how these disturbances are different from non-human disturbances (10 points)?
You need to describe the types of disturbances, such as clearcutting, urbanization, pollution, climate change, etc., and give a clear indication of what's happening to populations in natural communities. The main differences between these disturbances and natural ones are their persistence, their extent, and their frequency.
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