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10 Cards in this Set
- Front
- Back
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very small animal don't require a special transport system. Why? |
Because they have a large surface-area-to-volume ratio, so they can get the substances they need and excrete the substances they don't need by diffusion alone. |
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Larger organisms require a special transport system. Why? |
Larger organisms have smaller surface-area-to-volume ratio, meaning nutrients and gases would need to travel at a faster rate and a larger distance to the centre of the organism and keep all the cells alive. |
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Animals that are more active need special transport system. Why? |
because they use up food and oxygen more quickly and produce waste products faster |
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There are two types of circulatory system |
1.) single circulatory system 2.) double circulatory system |
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Single circulatory system |
a circulation in which the blood flows through the heart once during each circulation of the body (e.g. fish) |
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double circulatory system |
a circulation in which the blood flows through the heart twice during each circulation of the body (e.g. mammals) |
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advantages of The double circulatory system: |
the heart can increase the pressure of the blood after it has passed through the lungs. Which allows animals to be more active, since blood can reach their respiring tissue faster due to higher pressure |
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single circulatory system on fishes |
In the single circulatory system, the blood pressure is limited by the delicate tiny capillaries in the gills. Fishes are not as active as mammals so this system is sufficient to their needs. |
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open circulatory system |
the blood is not always in the vessel (e.g. insects) |
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closed circulatory system |
the blood is always in the vessels (e.g. fish) |
