Question

What is the difference between anisogamy and oogamy?

Answer 1

Hint: Plants have three types of sexual reproduction: anisogamy, isogamy, and oogamy. These three types of sexual reproduction represent three stages of plant evolution. Male gametes are referred to as sperm cells, while female gametes are referred to as egg cells.

Complete answer:
Anisogamy (also known as heterogamy) is a sexual reproduction method that involves the union or fusion of two gametes that differ in size and/or form. (Anisogamous and anisogamic are related adjectives.)
Oogamy is the most common type of sexual reproduction. It is a type of anisogamy (heterogamy) in which the female gamete (egg cell) is significantly larger and non-motile than the male gamete.
The difference between anisogamy and oogamy is as follows:

Anisogamy	Oogamy
Anisogamy is the fusion of gametes in dissimilar sizes.	Oogamy is the fusion of large immotile female gametes with small motile male gametes.
Both male and female gametes are either motile or immotile.	The egg cell is immotile and the sperm cell is motile.
The second stage of evolution is the sexual process.	The third stage of evolution is the sexual process.
Occurs in some fungi, higher invertebrates, and all vertebrates.	Found in higher groups of algae-like volvox and Oedogonium, plants like bryophytes ferns and gymnosperm.

Note: The first stage of the sexual process is isogamy. Algae, fungi, and lower plants all contain it. Isogamy gives rise to anisogamy. Isogamous gametes cannot be distinguished as male or female. Isogamy is the union of two gametes that have similar morphology in terms of shape and size. The only difference between them is in their physiology. Both isogamous gametes are motile because they are flagellated.