Camels - Adaptations to Extreme Environments
The Camel: How it has Adapted
Organisms exist in many environments, some are arid, some flooded, some are basic, some acidic, some are hot, and some are cool. Regardless of the conditions, animals have adapted themselves to survive in their surroundings. One of the main ecosystems that is classed as an extreme environment is the desert ecosystem. A classic example of a desert is the Sahara. Aridity is a characteristic shared amongst all deserts. As reported by Smith (2013), the reason most deserts are arid is because of uneven levels of evapotranspiration and precipitation. Aswel as adapting to very dry conditions, organisms in a desert ecosystem have also adapted to hot temperatures. The temperatures range from as high as 40oC during the day to as low as below freezing during the night due to lack of cloud cover.
Evolution:
As wrote by Long & Savage (1986) in the late Eocene period and to the end of Miocene, camels evolved and diversified solely in North America. During this time they were similar in size to rabbits, and their feet contained four toes. In Oligocene times, camels were similar in size to goats, with the lost of the lateral toes, with the remaining digits showing signs of evolution. During the Miocene time, camels adapted a new of walking, it is know as pacing gait. This is where the camel moved both left or both right legs in one movement, instead of opposite legs. During this time camels feet produced pad like structures, which helped them from sinking in soft terrain i.e sand. Then they arrived in South America during the Plio-Pleistocene times. This is where they diversified into 2 more genus under Camelinae family of the more known species, llama and alpaca, and 2 less known, guanaco and vicuna. As this happened, they crossed into the 'Old World ', where they then spread across Europe, Asia and Africa, this is where they branched out into the 'single humped ' Camelus Dromedarius, and 'double humped ' Camelus Bactrianus.
Organisms exist in many environments, some are arid, some flooded, some are basic, some acidic, some are hot, and some are cool. Regardless of the conditions, animals have adapted themselves to survive in their surroundings. One of the main ecosystems that is classed as an extreme environment is the desert ecosystem. A classic example of a desert is the Sahara. Aridity is a characteristic shared amongst all deserts. As reported by Smith (2013), the reason most deserts are arid is because of uneven levels of evapotranspiration and precipitation. Aswel as adapting to very dry conditions, organisms in a desert ecosystem have also adapted to hot temperatures. The temperatures range from as high as 40oC during the day to as low as below freezing during the night due to lack of cloud cover.
Evolution:
As wrote by Long & Savage (1986) in the late Eocene period and to the end of Miocene, camels evolved and diversified solely in North America. During this time they were similar in size to rabbits, and their feet contained four toes. In Oligocene times, camels were similar in size to goats, with the lost of the lateral toes, with the remaining digits showing signs of evolution. During the Miocene time, camels adapted a new of walking, it is know as pacing gait. This is where the camel moved both left or both right legs in one movement, instead of opposite legs. During this time camels feet produced pad like structures, which helped them from sinking in soft terrain i.e sand. Then they arrived in South America during the Plio-Pleistocene times. This is where they diversified into 2 more genus under Camelinae family of the more known species, llama and alpaca, and 2 less known, guanaco and vicuna. As this happened, they crossed into the 'Old World ', where they then spread across Europe, Asia and Africa, this is where they branched out into the 'single humped ' Camelus Dromedarius, and 'double humped ' Camelus Bactrianus.
References: Jeremy M.B. Smith desert 2013. Encyclopædia Britannica Online. Retrieved 01 March, 2013, from http://www.britannica.com/EBchecked/topic/158992/desert Köhler-Rollefson, Ilse U, (1991). Camelus Dromedarius. Mammalian Species. 375 (1-8), pp.1-4 Mares, Michael A., (1999). Encyclopaedia of Deserts. 1st ed. Oklahoma: University of Oklahoma Press. Richards, S.A., 1973. Adaptation to heat. In Temperature regulation. London, Wykeham Publications, pp. 191-197 as cited by Mukasa-Mugerwa, E., (1981). The Camel (Camelus Dromedarius): A Bibliographical Review. 1st ed. Ethiopia: International Livestock Centre of Africa Savage R. J. G & Long, M. R., (1986). Mammal Evolution. 1st ed. United Kingdom: Facts on File & The British Museum. Schmidt-Nielsen, K. 1964. The Camel. In Desert Animals: physiological problems of heat and water. Oxford, Clarendon press, 277 pp as cited by Mukasa-Mugerwa, E., (1981). The Camel (Camelus Dromedarius): A Bibliographical Review. 1st ed. Ethiopia: International Livestock Centre of Africa