Question

Shark	60cm alimentary canal	42cm body length
frog	18cm alimentary canal	28 cm body length
rat	40cm alimentary canal	16.8 cm body length
human	194cm alimentary canal	57 cm body length

How does the length of the alimentary canal correlate with the diet of an organism?

How does the length of the alimentary canal correlate with the metabolic activity level of the organisms?

How does the length of the alimentary canal correlate with the evolutionary history of the organisms ?

Answer 1

1 - How does the length of the alimentary canal correlate with the diet of an organism?

The morphology of organisams digestive tract reflects their evolutionary adaptation to different diet.the digestive tracts of herbivorous mammals is much generally longer than that of carnivorous.the increased length especially of the small intestine allows for more time for the cellulose of plants cell wall to be broken down.generally carnivorous such as sharks have shorter intestine compared to herbivorous.Instead sharks have spiral valves which increase the surface area of intestine. Humans also have not as long as the herbivorous like horse cattle sheep etc or it certainly not short as carnivorous such as lions or dogs.Frogs are carnivorous and feed on small insects so it need relatively small intestine to its body size.

2 - How does the length of the alimentary canal correlate with the metabolic activity level of the organisms?

Increased length of digestive tract allows more time for digestion which means long and steady flow of energy which allows extended metabolic activities.But in small digestive tract the digestion will will be rapid flow of energy but for a short time as the food consumed easily get digested.

3 - How does the length of the alimentary canal correlate with the evolutionary history of the organisms ?

With the emergence of mammals the digestive system was modified in a variety of way depending on the animals diet.For example the cat has a simple large intestine where the horse has a long intestine.We can see many resemblance of human embryo with small level organisam . The human alimentary canal is as simple as the primitive gut of the gastrula in its original structure.The last section of alimentary canal the large intestine, is at first is a very simple short and straight tube which opens behind anus.It remains thus through out low level vertebrates. But grows considerably in mammals. Primitive organisam which feeds on small micro organisams don't require a very lengthy intestine but when they become adapted to various land conditions their alimentary canal become modified according to the diet of that animal.As said earlier herbivorous have develop a lengthy alimentary canal which help in plant cellulose digestion.