Surface Area Essay

509 Words3 Pages
Surface area is a principle concept related to many areas in biological functioning. Heat as well as substances can be transferred between and within the body and the environment. Explain the relationship between surface area and this transfer. (25 marks) Surface area can affect the rate of diffusion this can be seen in Fick’s law. Where increasing the surface area would increase the rate of diffusion. This means the larger the surface area the more substance will diffuse across the pathway in a given time. Surface area also affects heat loss in all organisms. Smaller animals have higher surface area to volume ratios meaning it is easier for them to exchange oxygen and nutrients which the animal needs, they also excrete there waste products such as carbon dioxide and urea. Most animals need to stay at roughly the same temperature so heat is also exchanged. The larger the surface area to volume ratio is the easier it will be for the animals to perform these exchanges. Gas exchange surfaces have to main adaptations, large surface area and they are thin, they will both increase the rate of diffusion. Single celled organisms don’t require gas exchange systems because they can absorb and release gases by diffusion through there outer surface because they have a relatively large surface area. Large organisms require gas exchange systems to acquire all the oxygen they need, fish for example have special adaptations because there is less oxygen in the water than in the air. Water containing oxygen, enters the fish through its mouth and passes through the gills. Each gill is made up of thin plates called gill filaments, which give a large surface area for the exchange of gases. The gill filaments are covered in lots of tiny structures called lamellae, which further increase the surface area for gas exchange. During digestion nutrients are absorbed in the small
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