Isogamy , anisogamy and oogamy considered to be more advance in evolution
Answers
Answer:
Oogamy
Explanation:
Sexual reproduction in plants is classified into isogamy, anisogamy and oogamy
Isogamy
The simplest type is isogamous sexual process (isogamy). In this case, both gametes are mobile and are absolutely identical in size and appearance. During the fusion they retain mobility by flagella at the front end of rounded or pear-shaped body. Isogamy occurs in lower plants — algae, fungi
Anisogamy (heterogamy)
The next step is heterogamous sexual process (heterogamy or anisogamy). In anisogamy both gametes are mobile, they have flagella, but differ in size. One of them, the smaller, has more mobility and is considered to be a male gamete. Another one, a little larger, is less mobile. In its plasma, there is a certain amount of reserve nutrients. It is considered to be a female gamete.
Anisogamy occurs only in lower plants, such as in some green algae (Chlamydomonas Braunii) and brown algae
Oogamy
The next stage is oogamous sexual process (oogamy). In this case, gametes sharply differ in shape, size and character. One of them — male — is very shallow, its protoplast consists mainly of the nucleus and a thin layer of the cytoplasm; in front of it there is a small amount of plasma, from which depart flagella. Male gamete is actively mobile and has a special name — spermatozoid. Female gamete is deprived of motility. It's called an egg or ovum. Its major protoplast has a large nucleus. The cytoplasm contains a large amount of nutrients (diagram 132, 3).
Oogamy occurs in all higher plants and in vast majority of lower plants.