Annelida Phylum
Annelids are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches. They are found in marine environments from tidal zones to hydrothermal vents, in freshwater, and in moist terrestrial environments.
Earthworms (Amynthas Srinan)
All worms have both male reproductive organs and female reproductive organs. This means that they are hermaphrodites. The female organs of a worm include the egg sacs and ovaries. The male organs are two pairs of testes, three pairs of seminal vesicles and sperm funnels. Despite the fact that worms have both male and female organs it must mate with another worm if it wants to reproduce. Most reproduction between amynthas takes place at night, on the surface.
Worms form cocoons that eventually develop into live worms. Each cocoon can produce up to 15 worms. In the cocoon, several eggs are fertilized. One earthworm can make up to three cocoons in one week. Cocoons take about 4 to 6 weeks to hatch. A worm is sexually mature in 4-6 weeks after it is born.
Worms form cocoons that eventually develop into live worms. Each cocoon can produce up to 15 worms. In the cocoon, several eggs are fertilized. One earthworm can make up to three cocoons in one week. Cocoons take about 4 to 6 weeks to hatch. A worm is sexually mature in 4-6 weeks after it is born.
Leech (Hirudo medicinalis)
Leeches are also hermaphrodites meaning that they have male and female reproductive systems. Even though this is the case, they cannot self-fertilize. They need another member of their species to reproduce. For most leeches it is impossble to self fertilize because of the positioning of their reproductive organs. During mating season, which typically runs through early June to August, leeches of reproductive maturity start producing sperm and eggs. The clitellum (band of tissues that secretes the cocoon) may become enlarged and visible during this time of year. When two leeches find one another and decide to mate, they line up with each other, and one will attach a sac filled with sperm (called a spermatophore) to the other. Once the sperm fertilizes the egg the cocoon starts to form around the eggs. After the cocoon hardens and develops the eggs hatch and are protected by their mothers.
Ragworms (nereididae)
Spawning in ragworms is caused by rise in temperature in the spring. A female ragworm's body becomes swollen with eggs. As the eggs develop, the female's body become fragile and eventually splits open, releasing all of her eggs into the burrow she lived in. Males are attracted to the burrow by pheromones and they ejaculate their sperm into the burrow. Still alive, The female draws the sperm down into the burrow and allows her eggs to be fertilized. The female dies after spawning. Other species are hermaphrodites and reproduce through self- fertilization.
Ragworms, as babies, usually look like miniature versions of mature ragworms. They may change in color as they mature however. It is unknown how long it takes for a ragworm to reach maturity. It is likely that the time it takes varies between species.
Ragworms, as babies, usually look like miniature versions of mature ragworms. They may change in color as they mature however. It is unknown how long it takes for a ragworm to reach maturity. It is likely that the time it takes varies between species.