A few forms have reduced or lost their photosynthetic capacities and are entirely heterotrophic. Most algae are photoautotrophic some forms, however, are mixotrophic and derive energy both from photosynthesis and uptake of organic carbon by osmotrophy, myzotrophy, or phagotrophy. Unlike vascular plants, the algal body (thallus) lacks organ differentiation although some forms have developed structures functionally similar to roots, shoot axes, and leaves. The algae are a large informal grouping of heterogeneous, polyphyletic, or paraphyletic groups of primarily aquatic organisms ranging from tiny, flagellated unicells only a few microns in diameter to multicellular organisms up to 80 m long, such as the giant kelps. Algae are critical in modern aquatic ecosystems, not only in producing oxygen for other aquatic life, but also in serving as primary producers of organic matter at the base of the food web. Michael Krings, in Paleobotany (Second Edition), 2009 Publisher SummaryĪlthough algae thrive in a spectrum of habitats, including Antarctic ice, rock, and tree surfaces, animal fur, human and animal skin, and desert sand, most forms are aquatic. Gerbils produce and excrete a small amount of concentrated urine and dry feces per day ( Alderton, 1986) therefore they require less frequent cage changing than other laboratory rodents. The digestive system is also very efficient at absorbing and retaining water, and water can be stored in fat cell layers. Ninety-six percent of their nephrons are long loop which allows them to efficiently concentrate their urine ( Ichii et al., 2006). The ratio of long-loop nephrons to short-loop nephrons in gerbils is high. Gerbils can obtain sufficient water from their diet and their kidneys have a highly efficient urine-concentrating capacity to ensure adequate hydration ( Goyal et al., 1988). They have a unique water metabolism in that they require very little water to function ( Winkelmann and Getz, 1962). Gerbils have an excellent ability for thermoregulation, and they have a high level of heat tolerance. Since they are desert animals, gerbils have several characteristics that have allowed them to adapt to dry environments. West, in The Laboratory Rabbit, Guinea Pig, Hamster, and Other Rodents, 2012 Genitourinary System Some desert animals (e.g., species of camelids) have been domesticated in Africa, Asia, and South America. The venoms of cobras, rattlesnakes, and gila monsters all have medicinal properties under certain circumstances. Recently, as a greater knowledge of the chemistry of some compounds produced by animals has occurred, they have found even greater use. Animals ranging from beetle larvae to large antelope have been harvested for food, clothing, weapons, and medicines. Other species worldwide have been used as sources of anti-diabetics, the basis for cosmetics, fibers for weaving and other uses, plant growth regulators, surfactants, waxes and many other uses.ĭesert animals have been used in a variety of ways. Similarly, Acacia is used for food and fuel but may be more important as a source of commercial gums and tannins. Larrea, occurring in both the North and South American warm deserts, has great potential for commercialization because of its antifungal properties and nutritious forage. Many species have turned out to be good forage plants, especially some in the genus Atriplex. A few examples should suffice: in North America guayale ( Parthenium argentatum) was grown as a substitute for rubber for a period of time jojoba ( Simmondsia) oil appears in a variety of beauty products in the Sudan Blepharis has wound healing properties Agave is used in Mexico to produce an alcoholic beverage that is known worldwide Schinus, from the Atacama Desert, has proven to have insecticidal activity, as does Calotropis in India. The list of desert animals and plants that are of direct value to human beings is as long as the uses to which they are put. Uses of Desert Organisms and Their Products MacMahon, in Encyclopedia of Biodiversity, 2001 X.B.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |