Respiration

Respiration RespirationRespiration is a physical process in which living organisms take in oxygen from the surrounding medium and emit carbon dioxide. the term respiration is also used to refer to the liberation of energy, within a cell. from fuel molecules such as carbohydrates and fats. Carbon dioxide and water are the products of this process, which is sometimes called cellular respiration to distinguish it from the physical process of breathing.Small organisms of the kingdoms Protista and Prokaryotae have no specialized respiratory mechanisms; instead, they rely on the diffusion of oxygen and carbon dioxide across a cell membrane. The concentration of oxygen in the organism is less than that of the surrounding air or water, and the concentration of carbon dioxide is greater. As a result, oxygen diffuses into the organism, and carbon dioxide diffuses out.In aquatic lower animals that are more complex than sponges, a circulating medium carries the respiratory gases from outer tissues to cells that are distant from the sight of gas exchange.Anatomy of the lungs and heartThese animals have gills, which auxiliary respiratory mechanisms keep a constant current of fresh water flowing. The gases are diffused through the epithelium of the gill, and the extended surface, produced by the branching of the gills, enables large quantities of blood to be oxygenated in a short time.The respiratory and circulatory systems of air breathing animals have become adapted and modified for life in oxygen deficient environments. For example, people living in higher altitudes would have larger lungs than people living at lower altitudes. Humans respire through their lungs, as do most mammals and reptiles. Within the thorax, the lungs are held close to the body wall by atmospheric pressure. When the thorax expands, the lungs fill with air drawn through the upper respiratory passages. Relaxation of the muscles expanding...

Vaquita Facts and Conservation Information

Vaquita Facts and Conservation Information The vaquita (Phocoena sinus), also known as the Gulf of California harbor porpoise, cochito or Marsopa vaquita is the smallest cetacean. It is also one of the most endangered, with only about 250 remaining. The word vaquita means small cow in Spanish. Its species name, sinus is Latin for gulf or bay, referring to the vaquitas small range, which is restricted to coastal waters off the Baja Peninsula in Mexico. Vaquitas were discovered fairly recently - the species was first identified based on skulls in 1958 and live specimens were not observed until 1985. You can read more about the vaquitas discovery here. Description Vaquitas are about 4-5 feet long, and weigh about 65-120 pounds. Vaquitas are gray, with darker gray on their back and lighter gray on their underside. They have a black eye ring, lips and chin, and pale face. Vaquitas lighten in color as they age. They also have a recognizable triangular-shaped dorsal fin. Vaquitas are shy around vessels, and typically are found singly, in pairs or in small groups of 7-10 animals. They may stay underwater for a long time. The combination of these characteristics can make vaquitas difficult to find in the wild. Classification Kingdom: AnimaliaPhylum: ChordataSubphylum: VertebrataSuperclass: Gnathostomata, TetrapodaClass: MammaliaSubclass: TheriaOrder: CetartiodactylaSuborder: CetancodontaSuborder: OdontocetiInfraorder: CetaceaSuperfamily: OdontocetiFamily: PhocoenidaeGenus: PhocoenaSpecies: sinus    Habitat and Distribution Vaquitas have one of the most limited home ranges of all cetaceans. They live in the northern end of the Gulf of California, off the Baja Peninsula in Mexico, in murky, shallow waters within about 13.5 miles of shore. Click here for a sightings map. Feeding Vaquitas feed on schooling fish, crustaceans and cephalopods. Like other odontocetes, they find their prey using echolocation, which is similar to sonar. The vaquita emits high frequency sound pulses from an organ (the melon) in its head. The sound waves bounce off objects around them and are received back into the dolphins lower jaw, transmitted to the inner ear and interpreted to determine the size, shape, location and distance of prey. Vaquitas are toothed whales, and use their spade-shaped teeth to capture their prey. They have 16-22 pairs of teeth in their upper jaw and 17-20 pairs in their lower jaw. Reproduction Vaquitas are sexually mature at about 3-6 years of age. Vaquitas mate in April-May and calves are born in the months of February-April after a 10-11 month gestation period. Calves are about 2.5 feet long and weigh about 16.5 pounds at birth. The maximum known lifespan of an individual vaquita was a female who lived 21 years. Conservation There are an estimated 245 vaquitas remaining (according to a 2008 study), and the population may be declining by as much as 15% each year. They are listed as critically endangered on the IUCN Red List. One of the biggest threats to vaquitas is entanglement or being caught as bycatch in fishing gear, with an estimated 30-85 vaquitas taken incidentally by fisheries each year (Source: NOAA). The Mexican government began developing a Vaquita Recovery Plan in 2007, putting efforts into place to protect the vaquita, although they continue to be affected by fishing. Click here to learn how you can help vaquitas. References and Further Information Gerrodette, T., Taylor, B.L., Swift, R., Rankin, S., Jaramillo-Legorreta, A.M., and L. Rojas-Bracho. 2011. TI - A combined visual and acoustic estimate of 2008 abundance, and change in abundance since 1997, for the vaquita, Phocoena sinus. Marine Mammal Science, 27:2, E79-E100.Marine Mammal Commission. Vaquita (Phocoena sinus). Accessed May 31, 2012.NOAA Fisheries Office of Protected Resources. 2011. Gulf of California Harbor Porpoise/Vaquita/Cochito (Phocoena sinus). Accessed May 31, 2012.OBIS-SEAMAP. Gulf of California Harbor Porpoise (Phocoena sinus). Accessed May 31, 2012.Perrin, W. (2010). Phocoena sinus Norris McFarland, 1958. In: Perrin, W.F. World Cetacea Database. Accessed through: World Register of Marine Species at marinespecies.org/aphia.php?ptaxdetailsid343897. Accessed May 31, 2012.Phocoena sinus, In Palomares, M.L.D. and D. Pauly. Editors. 2012. SeaLifeBase. World Wide Web electronic publication. www.sealifebase.org, version (04/2012). Accessed May 31, 2012. Rojas-Bracho, L., Reeves, R.R., Jaramillo-Legorreta, A. Taylor, B.L. 2008. Phocoena sinus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. . Accessed May 29, 2012.Rojas-Bracho, L. P. sinus. Accessed May 31, 2012.Vaquita: Last Chance for the Desert Porpoise. Accessed May 31, 2012.Viva Vaquita. Accessed May 31, 2012.