Annelida Reproduction
Anneldia, also called anneldids, are a phylum of worms, with about 22,000 living species. Most known among those species are earthworms, leeches, and ragworms. In the phylum are two classes; Polychaetes, and Ciltellates. Subclasses of Ciltellates are Oligochaetes, and Hirudinea.
Most polychaetes reproduce sexually, however some reproduce asexually as well. Some are seperate sexes (male or female) while others are hermaphroditic, which means that they have both male and female reproductive systems. Methods of reproduction vary among the different species that make up the polychaete class, but most take place in water. One way that polychaetes reproduce is by releasing eggs and sperm into the water, where larval developments begin to take place. Larvae can stay in the water for a short as hours, and as long as months, depending on the species. After a certain period of time, the larvae settles on the ocean floor, and develops into adult worms. The polychaetes that do reproduce asexually are also capable of sexual reproduction.
Some clitellates are capable of both sexual and asexual reproduction. An example of this is Oligochateas, which mostly reproduce asexually, but when there are changes in their environment, they sometimes reproduce sexually. Most clitellates cross-fertilize by copulation. For example, leeches experience cross fertilization with a sperm filled sac called a spermatophore. Spermatophores involve the direct transfer of sperm to the ventral body surface of the other party involved in the cross fertilization. The sperm then exits the spermophore and goes to the ovaries, where the other party's eggs are fertilized.
Most polychaetes reproduce sexually, however some reproduce asexually as well. Some are seperate sexes (male or female) while others are hermaphroditic, which means that they have both male and female reproductive systems. Methods of reproduction vary among the different species that make up the polychaete class, but most take place in water. One way that polychaetes reproduce is by releasing eggs and sperm into the water, where larval developments begin to take place. Larvae can stay in the water for a short as hours, and as long as months, depending on the species. After a certain period of time, the larvae settles on the ocean floor, and develops into adult worms. The polychaetes that do reproduce asexually are also capable of sexual reproduction.
Some clitellates are capable of both sexual and asexual reproduction. An example of this is Oligochateas, which mostly reproduce asexually, but when there are changes in their environment, they sometimes reproduce sexually. Most clitellates cross-fertilize by copulation. For example, leeches experience cross fertilization with a sperm filled sac called a spermatophore. Spermatophores involve the direct transfer of sperm to the ventral body surface of the other party involved in the cross fertilization. The sperm then exits the spermophore and goes to the ovaries, where the other party's eggs are fertilized.