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:
“It is so characteristic, that just when the mechanics of reproduction are so vastly improved, there are fewer and fewer people who know how the music should be played.”
—Ludwig Wittgenstein (1889–1951)
“He is asleep. He knows no longer the fatigue of the work of deciding, the work to finish. He sleeps, he has no longer to strain, to force himself, to require of himself that which he cannot do. He no longer bears the cross of that interior life which proscribes rest, distraction, weaknesshe sleeps and thinks no longer, he has no more duties or chores, no, no, and I, old and tired, oh! I envy that he sleeps and will soon die.”
—Albert Camus (1913–1960)
“The lifelong process of caregiving, is the ultimate link between caregivers of all ages. You and I are not just in a phase we will outgrow. This is life—birth, death, and everything in between.... The care continuum is the cycle of life turning full circle in each of our lives. And what we learn when we spoon-feed our babies will echo in our ears as we feed our parents. The point is not to be done. The point is to be ready to do again.”
—Paula C. Lowe (20th century)