Reference no: EM132405301

1. Plants never consider Ammonia or organic nitrogen a waste product. Rather, it is an always welcome fertilizer.
2. All animals have a method of nitrogen disposal.
3. We are familiar with lipid storage (fat) and carbohydrate storage (starch/glycogen). Protein and nucleic acid lack storage forms (eggs are exception).
4. People on vegetarian diets often supplement with milk and cheese products. Strict vegetarians have diets filled with nuts and beans (the edible seeds).
5. When we eat "meat", muscle tissue is favored because of its main ingredient. White meat, red meat, fish, and shellfish all have it.

Q1: Based on 1-5 above; What can you say about the lifestyle and diet of animals (compared to plants)? Mammals (compared to lizards)? What can you say about the diet of human ancestors (compared to modern humans)? Does disposal seem the best way to deal with excess nitrogen?

Q2: Birds and lizards adapted to terrestrial life by using a waterless nitrogen excretion system while mammals continued to use the water based system of amphibians. Can you think of reasons for continuing the water based system?