Question

A) What are different stages of development in animals? What is the importance of each?

B) Describe two specialization that help increase the surface area of small intestine for absorption of nutrients from digested food.?

C) Discuss how gut microorganisms play an important role in metabolism.?

Answer 1

1. Different stages of development in animals and their importance:
(a) Gametogenesis: It consists of oogenesis or spermatogenesis. (Formation of egg cells or sperm cells).
(b) Fertilization: It is signified by the fusion of teo cell's nuclei when the sperm cell enters into the egg cell. Zygote is formed.
(c) Embryogenesis: It is the stage of the development of the embryo.
(d) Metamorphosis: The embryo turns into an adult.
All the steps are important from their individual perspectives fot the proper growth of the individual.

2. Specialisations that helps small intestine to increase surface area:
(a) The surface area is increased by 10 fold with help of Villi which is present in the Mucosa.
(b) There are folds called lumenal surface in the epithelial cells, know as Microvilli which increases the surface area by 20 folds.

3. The gut microbes helps in the energy harvest process of host. It does it by converting the inaccessible nutrient sources like plant polyssachharides into readily absorbable metabolites.