What organ do annelids use to reproduce?

What organ do annelids use to reproduce?

In some annelids, gonads occur in several successive body segments. This is true, for example, in polychaetes, most of which are dioecious. Testes and ovaries usually develop, though not invariably, in many body segments; and the sperm and eggs, often in enormous numbers, are stored in the coelom.

Do annelids have internal or external fertilization?

In Annelids external fertilisation takes place in dioecious organism andinternal fertilisation in monoecious or hermaphroditic organism. In molluscs,fertilization is either internal orexternal (dioecious animals).

What makes an annelid an annelid?

annelid, phylum name Annelida, also called segmented worm, any member of a phylum of invertebrate animals that are characterized by the possession of a body cavity (or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name.

Which type of annelid can be an external parasite?

Leeches probably evolved from oligochaetes, and are the most specialized of annelids. Some leeches are predaceous, but most are external parasites of other animals, and have several adaptations for a parasitic lifestyle.

Which of the following is annelid?

The annelids /ˈænəlɪdz/ (Annelida /əˈnɛlɪdə/, from Latin anellus, “little ring”), also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches.

How do annelid worms reproduce?

Most species of annelids can reproduce both asexually and sexually. Asexual reproduction may occur by budding or fission. Sexual reproduction varies by species. In some species, the same individual produces both sperm and eggs.

Which annelid has external fertilization direct development?

In this way, oligochaetes have external fertilization. Leeches carry out a slight variation on this process by using the sperm to fertilize the eggs while they are still within the body. Once they are fertilized, the eggs are then deposited into the cocoon.

What makes an annelid an annelid for kids?

The animals in the Annelida are segmented worms. They have no legs, and no hard skeleton. Unlike mollusks, annelid bodies are divided into many little segments, like rings joined together. There are many other kinds of worms, but only annelids are segmented this way.

Why are annelid eggs called spiral or determinate?

Annelid eggs, like those of flatworms and mollusks, exhibit spiral, or determinate, cleavage, so called because early differentiation of various regions occurs; in indeterminate cleavage (in echinoderm and chordate eggs), early differentiation does not occur.

What kind of reproduction does an annelid have?

Annelids are also fascinating in how they reproduce. Some reproduce sexually while other reproduce asexually. Those that reproduce sexually, like earthworms and leeches, are hermaphrodites, meaning that they have both male and female reproductive parts.

What kind of organism is an annelid earthworm?

Your first answer may be ‘I have no idea!’ but chances are good that you already know the answer to this question. Annelids are the organisms that belong to the phylum Annelida and if you’ve ever seen a wiggly earthworm, you’ve seen an annelid.

Why are annelids so important to the environment?

In addition to improving soil fertility, annelids serve humans as food and as bait. Scientists observe annelids to monitor the quality of marine and fresh water.