Lizzy

I am Masingita Lizzy Maluleke.I did Bachelor degree of Enviremental Sciences at the University of Venda for science and technology majored with Geography and Ecology and Resourse Managenment.I am presantly doing honours with the university of the Western Cape in Ecological Informatics.

Thursday, May 11, 2006

ADAPTATION REQUERED TO MAKE THE LAND LIFE TRANSITION FROM THE WATER TO LAND LIFE USING AMPHIMBIANS GROUP AS AN EXAMPLE


Amphibians are vertebrate animals that can inhabit on both land and in water, which lay their eggs in water. Some of these species have four feet and they do not have amniotic eggs. Amphibians was classify at the Amphibia. It was said that their transition from land to water was not completed because they live in water and this means that they require a transition from the aquatic to terrestrial environment and they first adapt air from the terrestrial environment. Species such as frog, tatropods and salamander etc are the example of amphibian’s animals.


The frog animals adapted to an arid and semi arid environment need water to lay their eggs meaning that water plays an important role during their reproduction. They lay their eggs inside the water, then the eggs will be hatched inside the water and the young eggs developed into adult. Small or adolescent fogs live in water and breathe with gills and adult live on land breathe through lungs. When adolescent reach sexual maturing stage, they goes back inside the water and spend a lot of time inside the water. Frogs feeds themselves on algae plants in water and when they are on land they eat insects such as flies etc. They depend on absorbing oxygen through their thin, wet skin.


Some of the amphibians manage their adaptation on land. Amphibian’s metamorphosis has four legs to support their body on the land. Their gills are replaced after being terrestrial dwellers and they also started to use lungs for breathing. Their skin change and develops glands to avoid loosing a lot of water from their body and this process is dehydration. They also develop eyelids on their eyes and they start to adapt vision when they are outside the water. They also develop an eardrum that locks off their middle ear. The species such as frog and toas lost their tails. Frogs uses their legs to swim in water and they jump when they are on land.


Early reptiles and other living organisms succeeded their adaptation on the land but frogs did not succeed because of the low biomass on the land and dry environment in dry areas. Amphibians are semi terrestrial inhabitant. Their skins are soft and moist meaning that they are at the higher risk of dehydration in the dry area. Their eggs were unprotected meaning that were not covered by the waterproof, these eggs must be laid near the plants that are found inside the water where they are fertilised. Some of these species place their eggs within their mouth and some place their eggs at their stomach after the external fertilization.


The declines in amphibian’s populations include population crashes and mass localization extinction and this is the threats to the global biodiversity. Amphibians started to decline after becoming a terrestrial dwellers and this caused by the limitation factors such as over exploitation, climate change, population growth, diseases, habitat distruction and modification. Most of an amphibians run away from the water to the land because of the above factors. The species manage to survive are frogs, tetrapod etc.
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Tetrapods species do not have amniotic eggs and they have adaptations to a terrestrial environment. Amphibians such as crocodiles lay their eggs in a mass of dead vegetation. Amphibians animals are adapted to the wetland or wet environment. They also have a skeleton bone and four legs which support them to stand on the land. The wetland is good for both arid and semi arid animals because water play an important role during their reproduction and on land they maintain their body temperature.


References:

Wikipedia contributors. Amphibians [Internet] wikipedia, the free encyclopaedia 2006 May 09, 12:25 UTC [cited May 11]. Available from http://en.wikipedia.org/wiki/Amphibians


Lizzy Maluleke
CSIR PTA
0001
Cell number 072 351 8488
Tell [012] 841 2133
Fax [012] 842 3676
E-mail mmaluleke@csir.co.za
Weblog: http://mmaluleke.blogspot.com

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