reproductive adaptations in animals

Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Premium Membership is now 50% off! The clasper, supported by modified fin cartilages, contains a groove along which sperm are conveyed into the uterus and is raised, or erected, by muscles at its base. We'll email you at these times to remind you to study. A peculiarity of the reproductive mechanism of a species that results in it being better fitted to its environment (for example, prolonged seed dormancy ). A longitudinal groove on the surface of the penis directs the flow of sperm. The latter, uncommon among fishes, amphibians, and birds, are present in all reptiles (except Sphenodon) and mammals. When a retractor muscle is present (wolf, fox, dog), it relaxes as erection occurs. The platypus (Ornithorhynchus anatinus) is an animal so full of adaptations that it is unlike any other animal in the world – Europeans first thought it was a hoax when settlers brought an example of the mammal back. In at least one teleost species, the female has a copulatory organ that she inserts into the genital pore of the male for receiving sperm. All mammals have internal fertilization and an erectile penis. All birds have internal fertilization, although they are not viviparous; most lack intromittent organs. One of its most interesting adaptations is its sixth sense; electroreception. Chickens have an organ consisting of a small amount of erectile tissue, but lymph vessels, rather than blood vessels, become engorged. The reproductive structures of many animals are very similar, even across different lineages, in a process that begins with two gametes–eggs and sperm–and ends with a zygote, which is a fertilized egg. Many animals are able to engage in certain behaviors which have no discernible function and may not be a part of adaptation. Functional adaptions are structures an animal needs to be able to function, so a fish living in water has gills to enable it to breath and function. In a few teleosts, hemal spines (ventral projections of vertebrae) form the skeleton of an intromittent organ. Australian fauna to ensure Fertilisation Survival of the embryo and of the young after. In some cattle, a sigmoid, or S-shaped, flexure bends the penis, which otherwise would be too long to fit into the preputial sac. Reproductive adaptations are characters and behaviours that relate to finding the ‘right’ mate, reproducing and raising young. The claspers of most male elasmobranchs are usually paired extensions of pelvic fins that are inserted into the female’s uterus for transfer of sperm. Fertilization among vertebrates may be external or internal, but internal fertilization is not always correlated with viviparity or the presence of intromittent (copulatory) organs. Erection of the mammalian penis is initiated typically by an increase in the volume of blood reaching the cavernous and spongy bodies, engorgement of the vessels, and consequent compression of the veins leaving the organ. In animals ranging from insects to humans, males produce sperm in testes, and sperm are stored in the epididymis until ejaculation. Female mammals have an erectile penile organ known as the clitoris in the floor of the urinogenital sinus or vagina. The spermatic duct of male mammals between the seminal vesicle and the prostatic urethra has a heavy muscular coat and serves as an ejaculatory duct. It is a permanent tubular extension of the cloaca and resembles a tail. In animals ranging from insects to humans, males produce sperm in testes, and sperm are stored in the epididymis until ejaculation. Shells of certain animal embryos such as reptiles and birds are examples of adaptation to a terrestrial environment. Topic 8: Reproductive Adaptations in Animals Part of the Evolution of Australian Biota Module Biology in Focus, Preliminary Course Glenda Childrawi and Stephanie Hollis DOT Points Describe some mechanisms found in. Occasionally, the intromittent organ is an asymmetrical tube that matches the asymmetrical genital opening of the female. The penis of marsupials is directed backward, and that of cats and rodents is directed backward, except during copulation. Male swans, ducks, geese, tinamous, ostriches, and some other ratites (flightless birds), however, have an erectile median penis like that of crocodiles and turtles.

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