What is the difference between Isogomy and Oogamy?

Isogomy:

1. Isogamy involves fusion of two morphologically similar and motile gametes.

2. The gametes are physiologically different. The common example of isogamy is seen in case of unicellular algae Chlamydomonas.

Oogamy:

1. Oogamy involves fusion of two morphologically dissimilar gametes. The female gamete is larger and non-motile while the male gamete is smaller and motile.

2. The gametes are also physiologically different. The examples are the higher group of algae like Volvox, Oedogonium, etc.