Life Cycle
With the exception of a few purely asexual species, the life cycle of cladocerans is dominated by asexual reproduction, with occasional periods of sexual reproduction; this is known as cyclical parthenogenesis. The system evolved in the Permian, at the same time that the Cladocera arose. When conditions are favourable, reproduction occurs by parthenogenesis for several generations, producing only female clones. As the conditions deteriorate, males are produced, and sexual reproduction occurs. This results in the production of long-lasting dormant eggs. These ephippial eggs can be transported over land by wind, and hatch when they reach favourable conditions, allowing many species to have very wide – even cosmopolitan – distributions.
Read more about this topic: Cladocera
Famous quotes containing the words life and/or cycle:
“On the death of a friend, we should consider that the fates through confidence have devolved on us the task of a double living, that we have henceforth to fulfill the promise of our friend’s life also, in our own, to the world.”
—Henry David Thoreau (1817–1862)
“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)