Sperm is the male reproductive cell , or gamete , in anisogamous forms of sexual reproduction forms in which there is a larger, female reproductive cell and a smaller, male one. Animals produce motile sperm with a tail known as a flagellum , which are known as spermatozoa , while some red algae and fungi produce non-motile sperm cells, known as spermatia. Sperm cells form during the process known as spermatogenesis , which in amniotes reptiles and mammals takes place in the seminiferous tubules of the testes. The spermatocytes then undergo meiosis , reducing their chromosome number by half, which produces spermatids.
Size matters when it comes to sperm dominance
Spermatozoon - Wikipedia
November 18, A tiny fruit fly has the bizarre distinction of possessing the longest sperm of any animal—20 times the length of its own body and 1, times that of human sperm. Not longer in proportion to its body size , just longer. It is a freakish extreme, but as a general rule, scientists have long known that the smallest animals have the biggest sperm , and vice versa.
In most living animals, egg cells are vastly larger than sperm cells. In humans, for example, a single egg is 10 million times the volume of a sperm cell. In a new study, Northwestern Engineering researchers found that competition and natural selection drove this curious size discrepancy.
Try out PMC Labs and tell us what you think. Learn More. Objective measurements are required for computer-aided sperm morphometric analysis CASMA machines to distinguish normal from abnormal sperm heads.