Question

Differentiate between direct and indirect development.

Answer 1

Hint: In mammals, development begins with a single cell called a zygote (a fertilised egg). Depending on the animal's categorisation, development might be direct or indirect. Direct and indirect development differ in their progression from fertilisation to sexually mature adulthood.

Complete step by step answer:
A fertilised egg that has begun to divide is called a zygote. The division of cells results in cell differentiation, which leads to the creation of an embryo. The egg yolk feeds the embryo, and the amount of yolk decides whether the animals will be deployed directly or indirectly. The following is a list of the differences between direct and indirect development:
Direct Development: It's a stage of development in which an animal is born as a miniature version of its adult form. There is no intermediary form, such as an animal's larva, in this sort of development. Animals that develop directly may have a substantial amount of yolk in their egg to feed their young, or the young may be fed directly by the mother's body. There is no metamorphosis. Fish, reptiles, birds, and mammals are among the animals that go through direct development.
Indirect Development: It is a stage of development in which an animal's birth form differs from its adult form. In this style of development, the embryo develops into a larval form after hatching from the egg. The larva goes through a metamorphosis phase to become an adult. Indirectly developed animals have very little yolk, and the larva develops and hatches quickly as a result of the lack of yolk. Indirect development occurs in amphibians, some echinoderms, and some arthropods such as insects.

Note: Butterfly and moth development is an example of indirect development. They grow through a transformation process. Complete and incomplete metamorphosis are the two forms of metamorphosis. Complete metamorphosis causes the young to look substantially different from adults, whereas partial metamorphosis causes the young to look like adults but without wings.