Animal Movement Questions
Bring on the tough stuff
1) What would it take for a human to have neutral buoyancy in a body of water?
2) What would happen to a snake if it did not have any scales on its belly?
3) At higher altitudes people (and probably animals) make more red blood cells than people living at sea level. Why do you think this is?
4) Which type of fish would likely drink water while it swims? Saltwater or freshwater?
5) Ectotherms have internal body temperatures which are likely to fluctuate, whereas endotherms keep a constant internal temperature. What can this tell about their enzymes and the temperatures at which they work?
6) If the lungs only had half as many alveoli as they currently do, how would this affect respiration and why?
7) Why are ventricles larger and more powerful than atria?
8) It's 2012. Russia gets very cold during the winter and warm during the spring and summer. Birds are only seen in the parks during the spring and summer months.
9) Your blood has too much of substance X in it. Substance X is normally found in your blood, but right now the level is way too high (which could be deadly). At what stages could homeostasis being failing?
10) You are an ectotherm. It is a chilly day outside and you have several errands that you need to accomplish. When do you do them and how do you prepare?
Possible Answers
1) What would it take for a human to have neutral buoyancy in a body of water?
Since neutral buoyancy means having the same density as the liquid, there are two options:
a) Modify the density of the human
b) Modify the density of the liquid
Modifying the density of the human is not really feasible, unless we allow props to be used. For example, we could increase the density by strapping on a heavy iron vest, which would increase the mass without changing the size very much. We could also attach a large balloon (AKA a life vest), which would increase our size without increasing out mass. Both situations would modify out density.
Modifying the density of the liquid requires props too, like a lot of salt or other solutes. By increasing the mass of the water with solutes, we can increase the density of the water. In the Dead Sea, the concentration of salt is so high that the density of the water is increased and people can float.
2) What would happen to a snake if it did not have any scales on its belly?
It would have serious trouble moving. Scales are an important part of the snake because they provide grip on the ground that the snake uses to push off with. To study this, scientists took a snake and put in on a board, and then tilted it to see how long the snake could hold on before it slid down. The snake could stay on the board for quite a while. However, when they covered the snake's scales it could not hold on at all, even though its movement was not restricted in any other way.
3) At higher altitudes people (and probably animals) make more red blood cells than people living at sea level. Why do you think this is?
This is because there is less oxygen at higher altitudes, so people have adapted to try and be more efficient at capturing the small amount that is available. This is why people train at higher altitudes for various sporting events.
4) Which type of fish would likely drink water while it swims? Saltwater or freshwater?
The salt-water fish is much more likely to drink water while it swims. Saltwater fish are hypotonic to their environment. They have less salt inside than the water has outside. This means that water will be moving out of them and into the surrounding sea water. By drinking water as they swim, they can balance this effect. Drinking water also helps dilute the salts that are diffusing into them from the outside.
5) Ectotherms have internal body temperatures which are likely to fluctuate, whereas endotherms keep a constant internal temperature. What can this tell about their enzymes and the temperatures at which they work?
The chart below shows the amount of energy that a lizard or a mouse can produce at different temperatures. It demonstrates so that the cells in poikilotherms can successfully perform chemical reactions at a wide range of body temperatures. Homeotherms must keep a constant body temperature in order for their cells to function.
The lizard is an ectotherm, and the mouse is an endotherm. As the lizard's internal body temperature changes, its cells are still capable of producing energy. The mouse, on the other hand, only has a narrow range of internal temperatures at which its cells can function. The mouse is capable of creating more energy than the lizard, but only within a narrow range of temperature.
6) If the lungs only had half as many alveoli as they currently do, how would this affect respiration and why?
It would decrease the amount of oxygen that can be exchanged. The alveoli are the sites of gas exchange in the lungs. Many alveoli are needed so that the surface area of the lungs can be increased and a large amount of gas exchange can take place. If there were less alveoli, there would be less available locations for gas exchange.
7) Why are ventricles larger and more powerful than atria?
Ventricles are more powerful than atria because they need to pump the blood a further distance than the atria. Atria only pump the blood into their ventricle neighbors, but the ventricle needs to pump the blood out of the heart and to other places in the body. In mammals with a 4-chambered heart, the left ventricle is more powerful than the right ventricle. This is because the right ventricle pumps the blood through the pulmonary loop to the lungs and back to the heart, but the left ventricle pumps the blood through the systemic loop which takes it to all the cells in the body.
8) It's 2012. Russia gets very cold during the winter and warm during the spring and summer. Birds are only seen in the parks during the spring and summer months.
Advance to the year 2060. Russia now has a very temperate climate that never gets very cold. Do you think this would affect how many birds are around in winter? Why?
Yes, it is likely that there would now be birds around during the winter months. The likely reason that birds were not seen during the winter months in 2012 was because they migrated to warmer climates to escape the cold weather. In 2060, the birds would not need to travel for a warmer climate since the climate is temperate all year long and would likely stay in Russia the entire year.
9) Your blood has too much of substance X in it. Substance X is normally found in your blood, but right now the level is way too high (which could be deadly). At what stages could homeostasis being failing?
Homeostasis could be failing at three different stages.
1- Sensing: This is the stage where your body takes measurements of the levels of substance X in the blood. If the sensors are broken then your brain will never know that there is a too much substance X in the blood and cannot order a response to fix the problem.
2- Processing: This is the stage where your brain receives the measurements from the sensors and decides if the level of substance X is acceptable or if it is too high or too low. If the brain-processing center is broken then it will not be able to order a response when the sensors detect a high level of substance X.
3- Response: This is the stage where the special response teams in your body receive orders from your brain to do things with reduce the level of substance X in the blood. If the response team cannot do their job, then the body will not be able to reduce the levels of substance X even if the sensors are working and the brain processing center is working and ordering a response.
10) You are an ectotherm. It is a chilly day outside and you have several errands that you need to accomplish. When do you do them and how do you prepare?
Ectotherms require heat from outside sources. On a chilly day they try not to move as much because they do not want to lose heat. They usually drop their metabolism and their body temperature decreases and they are inactive.
So, if you are an ectotherm and you need to run some errands you better make sure you do them during the warmest part of the day, definitely do not do them when it is dark out! You can also prepare by finding a sunny place to sit and get as warm as possible so when you run your errands you will have a high starting temperature. If necessary plan your route so you are always in the sun as much as possible.