Name: Digestion in Grass-Eating Animals
Uploaded: 2019-07-19
Duration: 5 min 47 s
Description: Digestion in grass-eating animals involves the process of rumination. In this video, we will learn about the digestive system of ruminants and the importance...

Question

Study how the digestive system of humans has evolved with the evolution and change in eating habits.

Accepted Answer

Evolution of the human digestive system: The digestive system of different vertebrates however have similar basic evolutionary characteristics. The organs of the digestive system are modified and adapted according to feeding habits. This can be explained as follows:

All the vertebrates (fishes, amphibians, reptiles, birds and mammals) have mouth and oesophagus, stomach, small intestine, pancreas and large intestine. However, their size and structure differ from each other depending on their feeding habits.

The oesophagus is short in fishes and amphibians in comparison to reptiles birds and mammals. The stomach in fishes and amphibians is single-chambered, in birds, it is double-chambered (proventriculus and gizzard), in mammals, it is three-chambered (cardiac, fundic and pyloric). In fishes and amphibians, the intestine is short, in reptiles and birds and mammals, the intestine is long and highly coiled.

Human digestive system: The stomach of a human is divided into cardiac, pyloric and fundic part. It consists of gastric glands which secrete gastric juices for the digestion of proteins. The small intestine is large and curved and consists of villi for the maximum absorption of digested food. The large intestine is long for the maximum absorption of water.

Study how the digestive system of humans has evolved with the evolution and change in eating habits.

Important Questions on Nutrition in Animals

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