Cnidaria meaning "Sea Nettle"
Jellyfish
Jellyfish have a special reproduction cycle. Jellyfish do not have any specialized bodily system for reproduction. The male jellyfish releases its sperm in the water. The female carries her eggs in her mouth or stomach. When the sperm that are released in the water come in contact with the female's eggs, they get fertilized. In the embryonic stage, these fertilized eggs are stored in brooding pouches along the oral arms of the female or in her stomach. After the embryonic stage is over, the larvae get transformed into tiny planulae that are free swimming and they detach themselves from their mother's body. At this stage, they start sinking towards the deep end of the ocean until they attach themselves to a hard surface and the next stage in their reproduction cycle begins.
ASexual Reproduction Part: Once the planula has found a hard surface, it attaches itself to it at its base. It remains attached to the surface, and over time a new polyp gets formed from the trunk of the first polyp. This process is repeated innumerable times, until an entire colony of polyps is formed. The polyps of this colony are all connected to each other with small feeding tubes. This ensures that every polyp receives adequate nutrition irrespective of its place in the colony. This stage of jellyfish reproduction can last for years and the polyp colony can grow up to a tremendous size.
ASexual Reproduction Part: Once the planula has found a hard surface, it attaches itself to it at its base. It remains attached to the surface, and over time a new polyp gets formed from the trunk of the first polyp. This process is repeated innumerable times, until an entire colony of polyps is formed. The polyps of this colony are all connected to each other with small feeding tubes. This ensures that every polyp receives adequate nutrition irrespective of its place in the colony. This stage of jellyfish reproduction can last for years and the polyp colony can grow up to a tremendous size.
Anemone
The gonads are strips of tissue within the mesenteries. Both sexual and asexual reproduction can occur. In sexual reproduction males release sperm to stimulate females to release eggs, and fertilization occurs. Anemones eject eggs and sperm through the mouth. The fertilized egg develops into a planula, which settles and grows into a single polyp. Anemones can also reproduce asexually, by budding, binary fission (the polyp separates into two halves), and pedal laceration, in which small pieces of the pedal disc break off and regenerate into small anemones.
Coral
Corals reproduce sexually by either internal or external fertilization.
Internally fertilized eggs are brooded by the polyp for days to weeks. Free-swimming larvae are released into the water and settle within hours.
Externally fertilized eggs develop while adrift. After a few days, fertilized eggs develop into free-swimming larvae. Larvae settle within hours to days. Some corals are hermaphroditic (having both male and female reproductive cells). Others are either male or female. Both sexes can occur in a colony, or a colony may consist of individuals of the same sex. Synchronous spawning occurs in many corals. Polyps release eggs and sperm into the water at the same time. This spawning method disperses eggs over a larger area.
Often a polyp produced by sexual reproduction initiates growth of a colony asexually by budding. Budding occurs when a portion of the parent polyp pinches off to form a new individual. Budding enables the polyp to replicate itself several times and at the same time maintain tissue connections within the colony. Later, the same polyp may reproduce sexually.
Michael Rispoli
Internally fertilized eggs are brooded by the polyp for days to weeks. Free-swimming larvae are released into the water and settle within hours.
Externally fertilized eggs develop while adrift. After a few days, fertilized eggs develop into free-swimming larvae. Larvae settle within hours to days. Some corals are hermaphroditic (having both male and female reproductive cells). Others are either male or female. Both sexes can occur in a colony, or a colony may consist of individuals of the same sex. Synchronous spawning occurs in many corals. Polyps release eggs and sperm into the water at the same time. This spawning method disperses eggs over a larger area.
Often a polyp produced by sexual reproduction initiates growth of a colony asexually by budding. Budding occurs when a portion of the parent polyp pinches off to form a new individual. Budding enables the polyp to replicate itself several times and at the same time maintain tissue connections within the colony. Later, the same polyp may reproduce sexually.
Michael Rispoli