Reproduction and Life Cycle
When food is plentiful, many Hydra reproduce asexually by producing buds in the body wall, which grow to be miniature adults and simply break away when they are mature. When conditions are harsh, often before winter or in poor feeding conditions, sexual reproduction occurs in some Hydra. Swellings in the body wall develop into either a simple ovary or testes. The testes release free-swimming gametes into the water, and these can fertilize the egg in the ovary of another individual. The fertilized eggs secrete a tough outer coating, and, as the adult dies, these resting eggs fall to the bottom of the lake or pond to await better conditions, whereupon they hatch into nymph Hydra. Some, like Hydra circumcincta and Hydra viridissima, are hermaphrodites and may produce both testes and an ovary at the same time.
Many members of the Hydrozoa go through a body change from a polyp to an adult form called a medusa. However, all Hydra, despite being hydrozoans, remain as polyps throughout their lives.
Read more about this topic: Hydra (genus)
Famous quotes containing the words reproduction, life and/or cycle:
“As the twentieth century ends, commerce and culture are coming closer together. The distinction between life and art has been eroded by fifty years of enhanced communications, ever-improving reproduction technologies and increasing wealth.”
—Stephen Bayley (b. 1951)
“War is more like a novel than it is like real life and that is its eternal fascination. It is a thing based on reality but invented, it is a dream made real, all the things that make a novel but not really life.”
—Gertrude Stein (1874–1946)
“The Buddha, the Godhead, resides quite as comfortably in the circuits of a digital computer or the gears of a cycle transmission as he does at the top of a mountain or in the petals of a flower.”
—Robert M. Pirsig (b. 1928)