Reptiles, birds, and mammals insect reproductive system In insect: Studies in Hellenistic Theosophy and Gnosis. Covering the head of the sperm is a cap known as the acrosome, which contains enzymes that help sperm to enter an egg. If a man has undergone a vasectomy , he will have no sperm in the ejaculation. Biologists have well established that male sperm production relies on certain genes on the Y chromosome , which, when missing or defective, lead to such men producing little to no sperm in their testicles. Some dietary supplements have been marketed with claims to increase seminal volume. From Wikipedia, the free encyclopedia.
The flowering plant sperm cells are contained within pollen grains. The orchid 's twin bulbs were thought to resemble the testicles , which is the etymology of the disease orchiditis. Would you like to merge this question into it? Their clicks are among the most powerful sounds in the animal kingdom see above.
Spermaceti , the fine waxy oil produced by sperm whales, was in high demand. Because it now has 46 chromosomes, it is called a diploid , like ordinary cells of the body. The species name rex leads a scientist to believe that it is considerably large and common during the very end of the cretaceous epoch. Common minke whale B. University of California Press.
Please help improve this article by adding citations to reliable sources. In flowering plants , sperm nuclei are produced inside pollen. A recent discovery links hyperactivation to a sudden influx of calcium ion into the tails. Immature germ cells, called spermatogonia singular, spermatogonium , are located around the outer edge of these tubes next to the basal lamina, where they proliferate continuously by mitosis. In almost all embryophytes , including most gymnosperms and all angiosperms , the male gametophytes pollen grains are the primary mode of dispersal , for example via wind or insect pollination , eliminating the need for water to bridge the gap between male and female. In other projects Wikimedia Commons.