The process of sexual reproduction for cod involves the act of spawning, resulting in the egg and sperm coming together for fertilization in open water. The male and female swim as a pair in circles during the spawning process.Know More
A female cod can release between 3 million to 9 million eggs during a spawning season. The larger the female, the more eggs she produces each season, which lasts from January through April. Cod mate in the open sea in frigid waters with depths up to 660 feet. Their eggs, however, are very buoyant and float to the water's surface, where they are left unattended.
The fertilized eggs hatch in eight to 23 days, and very small larvae form. The cod larvae reaches a length of approximately 4 millimeters. During the first week of life, a cod larva lacks a fully developed mouth and relies entirely on an attached yolk sac for nutrition. Guided movement is also limited for a cod larva until the second to third week of life when it is able to use its fins for propulsion. Male cod reach sexual maturity between the ages of 2 and 4 years, while females reach sexual maturity between 5 and 6 years of age.Learn more about Animal Reproduction
Mammals reproduce sexually, via the union of sperm and egg cells. Except for five species of egg-laying mammals, called monotremes, all mammals give birth to live young.Full Answer >
Bettas, also known as Siamese fighting fish, reproduce via external fertilization, which means that the female releases eggs and the male releases milt. The male is responsible for creating a "bubble nest," which is where the eggs are kept until they hatch.Full Answer >
Disadvantages of external fertilization include a reliance on water and the large amount of wasted sperm and eggs that never reach a corresponding gamete, even when the organisms releasing the eggs and sperm are in close proximity. Additionally, the eggs released can have no shells, as these would stop sperm.Full Answer >
Platyhelminthes, also known as flatworms, are hermaphrodites, meaning individuals of the species produce both sperm and eggs. These are released from the platyhelminthes where they become cross-fertilized by other platyhelminthes. Two types of platyhelminthes, trematoda and cestoda, lay eggs constantly. The turbellarian class has a seasonal cycle. Turbellaria also reproduce asexually by dividing. Turbellaria are the only class able to regenerate body parts.Full Answer >