Question

1. in a food web, the arrows ______.

a. show the movement of carrying capacity
b. represent energy flow along increasing trophic level
c. suggest potential relationships of symbiotic organisms
d. point the direction of the animal or plant being eaten

1. white - tailed deer are commonly infected with a parasitic nematode (round worm) in their brain, often fatal to moose. this results in a situation where the more deer there are, the less moose can survive. what describes this phenomenon?

image: brain worm infected deer; causes death? brain worm infected with no noticeable effect? (image of deer and brain worm)
a. the deer population and the moose population are both limited by a common carrying capacity
b. the deer and the moose population compete because they are sharing the same food resource
c. food deer and the brain worm have the same trophic level
d. the deer population reduces the moose population due to a density - dependent factor

1. in general, consumers are able to store very few of the calories they consume. what happens to the remaining calories?

a. they are used to maintain body temperature.
b. they are lost as waste or heat.
c. they are used for movement.
d. all of the others.

Explanation:

Question 20

In a food web, arrows represent the flow of energy (and nutrients) from one organism (the prey or producer) to another (the predator or consumer) as one is eaten by the other. This flow of energy moves along trophic levels (from producers to primary consumers, then to secondary consumers, etc.). Option a is incorrect as carrying capacity is about population limits, not arrow meaning. Option c is incorrect as arrows don't directly suggest symbiotic relationships (symbiosis is a different interaction like mutualism, parasitism, etc., not just predation/feeding). Option d is incorrect as arrows point from the organism being eaten to the eater, not the direction the animal or plant is moving. So the correct answer is about energy flow along trophic levels.

The scenario is: more deer (with brain worms, but worms don't affect deer much) lead to fewer moose surviving. Deer and moose likely compete for the same food resources (since they are both herbivores or share a niche in the ecosystem). Option a: carrying capacity is the maximum population an environment can support, but the question is about the interaction between deer and moose, not a common carrying capacity limiting both. Option c: Deer are hosts for brain worms (parasite), moose are affected by brain worms (maybe parasite affects moose more), so deer and brain worm are host - parasite, moose and brain worm are also a relationship, but deer and moose are not at the same trophic level as competitors (they are both consumers, maybe same or similar trophic level, but the key is competition for resources). Option d: Density - dependent factors are factors whose effect depends on population density (like competition, predation, disease). But the deer population reducing moose population due to competition (for food) is more about interspecific competition for resources, not density - dependent factor in the way described (density - dependent would be like disease spreading more in dense populations, but here it's competition). So the best description is that deer and moose compete because they share the same food resource.

Consumers (organisms that eat other organisms) use calories (energy) from food. The main uses of energy in organisms are: maintaining body temperature (especially in endotherms, but even ectotherms use energy for basic functions), performing work (movement, cellular processes), and some is lost as waste (but not as heat - heat is a by - product of energy use). Wait, actually, when organisms consume calories (energy in food), they use energy for metabolic processes (which includes maintaining body temperature, especially in homeotherms), for movement (work), and some energy is lost as heat (due to inefficiencies in energy transfer and metabolic processes) and in waste (like undigested food, but the energy in waste is not used by the consumer). But the question is about the remaining calories after storing a few. In general, consumers use energy for maintaining body temperature (a), for movement (c), and some is lost as heat (b) (and also in waste, but the options given: a, b, c, and d (all of the others)). Let's analyze: When an organism consumes food, the energy is used for: 1. Basal metabolic rate (maintaining body temperature, cellular functions) - so a is correct. 2. Activity (movement) - so c is correct. 3. Energy is lost as heat (due to the second law of thermodynamics, energy transformations are not 100% efficient) - so b is correct. So the remaining calories (after storage) are used for maintaining body temperature, lost as heat, and used for movement. So the answer is d.

Answer:

b. Represent energy flow along increasing trophic level

Question 21