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

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 ...

Single molecule puts sperm on track

Sperm start their sprint to the ovum when they detect changes in the environment through a series of calcium channels arranged like racing stripes on their tails. A team of Yale researchers has identified a key molecule that ...

An important function of non-nucleated sperm

Some animals form characteristic infertile spermatozoa called parasperm, which differ in size and shape compared to fertile sperm produced by single males. Species that have been reported to produce parasperm include snails, ...

Could climate change cause infertility?

The scientific community has long held an understanding about the effect of temperature on sperm production in mammals, but this new study sheds light on how spermatogenesis in insects is hampered at extreme temperatures.

Researchers find a way to use CRISPR Cas-9 on reptiles

A team of researchers at the University of Georgia has found a way to use the CRISPR-Cas9 gene editing tool on reptiles. In their paper uploaded to the bioRxiv preprint server, the group describes the technique they developed ...

Screw-shaped bird sperm swim faster—but it comes at a cost

A study by Ph.D. student Hanna Nyborg Støstad has investigated the peculiar spiral shape of songbird sperm. Støstad compared sperm cells of 36 bird species including house sparrows and tree swallows, and found that species ...

WWF sounds alarm after 48 lbs of plastic found in dead whale

An 8-meter (26-foot) sperm whale was found dead off Sardinia with 22 kilograms (48.5 pounds) of plastic in its belly, prompting the World Wildlife Foundation to sound an alarm Monday over the dangers of plastic waste in the ...

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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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