Related topics: eggs · fertilizer · genes · infertility · females

From the tiny testes of flies, new insight into how genes arise

In the battle of the sexes, males appear to have the innovative edge—from a genetic standpoint, at least. Scientists are finding that the testes are more than mere factories for sperm; these organs also serve as hotspots ...

Mystery deaths of dolphins, whales off Tuscany

Thirty-two dolphins and two whales have been found dead off the Tuscan coast since the beginning of the year, the Italian region's environmental protection agency said Friday.

Competition leads to fathers who produce more male sperm

New research led by The University of Western Australia has shown that the social conditions that a male experiences while growing up can influence the amount of X and Y chromosome sperm that he produces as an adult.

Study: Lethal plastic trash now common in Greece's whales

A study of whales and dolphins that have washed up dead in Greece over a 20-year period has found alarmingly high levels of plastic trash—mostly bags—in the animals' stomachs, which can condemn them to a slow and painful ...

Female flies respond to sensation of sex, not just sperm

Female fruit flies can feel when a sexual partner is a good fit. Scientists have long known that proteins in a male fly's ejaculate make female flies temporarily lose interest in other partners. It's a trick male flies use ...

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Sperm

The term sperm is derived from the Greek word (σπέρμα) sperma (meaning "seed") and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a totipotent zygote is formed with the potential to develop into a new organism.

The spermatozoa of animals are produced through spermatogenesis inside the male gonads (testicles) via meiotic division. They are carried out of the male body in a fluid known as semen. Mammalian sperm cells can live for up to 3 days inside the female reproductive system.[citation needed]

Sperm cells in algal and many plant gametophytes are produced in male gametangia (antheridia) via mitotic division. In flowering plants, sperm nuclei are produced inside pollen.

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