Question

2. The surface area of the small intestine is far greater than that of any other digestive system organ. What is the functional significance of the increased surface area of the small intestine compared to other parts of the digestive system? Discuss the potential effects of the following on the reservoir of atmospheric carbon: (a) cutting down large tracts of rain forest and exporting the lumber; (b) burning fossil fuels on a global scale; and (c) warming its temperature increases) Think in terms of the input to and output from the atmospheric carbon reservoir: how might these activities change the balance? 3. the surface waters of the oceans. (Hint gases become less soluble in water as

Answer 1

surface area of small intestine:

The small intestine is the site where almost all digestion and absorption of nutrients and minerals from food takes place.The large surface area of the small intestine is very important because this is where nutrients from digestive food particles are absorbed into the surface lining cells and from there into the blood stream and lymphatics.The total surface area,stretched out,would be about the floor area of a small apartment.This large surface area allows ample interaction of digested molecules with the cell membranes so that absorption can occur efficiently.In otherwords, the increased surface area(in contact with the fluid in lumen) decreases the average distance travelled by the nutrient molecules so the effectiveness of diffusion increases.

Effects on the carbon reservoir:

a.cutting down large tracts of rain forest and exporting the lumber have a devastating effect on the climate.lumber is the conomically most important product from the rain forest,and has a value on the world market estimated at 7,000 million US dollars a year.Tropical rainforest deforestration contributes upto 30% of all the carbondioxide human beings add to the atmosphere (Lewis,1990).This lead to increase of co_{​​​​​2}​​​​ ratio in the atmospheric reservoir and cause global warming by releasing other gases which threatens agriculture and the quality of life worldwide.

b.Burning of fossil fuels:

when fossil fuels like coal and oil are burned,carbon is released into the atmosphere at a faster rate than it is removed.As a result,the concentration of carbon dioxide in the atmosphere increases.The ocean absorbs much of the carbon dioxide that is released by burning fossil fuels.This extra carbon dioxide is lowering the oceans pH through a process called ocean acidification.ocean acidification interferes with the ability of marine organisms to build their shells and skeletoskeleton

C.warming surface water of oceans:

CO_{​​​​​2} dissolves with the waters and then reacts with the water so that it dissociates into several ions.This dissociation means that oceans can hold a lot of carbon- about 80% of the active reservoir on earth.cold sea water can hold more CO2 than warm water.This means that are cool and are cooling tend to take up carbon and waters that are warming tend to emit carbon.As gases become less soluble in water as its temperature increases.warming the surface waters of the oceans ultimately decrease the carbon influx or input from the atmosphere into the ocean water.