Q2.Write a short note on stages of animals.
Answers
Answer:
Early Growth
Before reaching sexual maturity or adulthood, animals pass through a growing stage. Some species, most common among invertebrates and amphibians, go through metamorphosis during the growing period. Metamorphosis includes larval and pupal stages. Butterflies, grasshoppers, mosquitoes, frogs and salamanders are some examples of animals that undergo metamorphosis. Hormones, such as somatotropin, induce growth in animals.
Creating New Life
Animals reproduce in sexually or asexually. While sexual reproduction involves male and female gametes - the spermatozoid and the ovule - asexual reproduction depends on a single individual to generate new life. Hydras, sponges, starfish and flatworms of the class Turbellaria, know as planarians, can reproduce asexually, but most animals depend on sexual reproduction to reproduce.
The End of Life
After aging, animals end their life cycles by dying. Loss of hearing and sight, lack of energy, body weakness and illnesses are some signs of aging and often precede the natural death of an animal in the wild. Predators are more likely to die natural deaths, while prey species are likely to succumb to attack when they become too old to defend themselves properly. Different species have distinct lifespans. Among birds, parrots have the longest lifespans, living up to 100, while hummingbirds generally die before they reach 10 years of age.