SST | Aquatic environments | Terrestrial environments |
Vercosity: A measure of how difficult it is to move through a substance. | Aquatic animals are usually have a streamline shape to assist them with moving more easily through water. | An advantage over aquatic as it is easier for animals to move through air than water. |
Buoyancy: A measure of a substances ability to support or hold an object. | Water is more buoyant than air. i.e a cork in air compared to a cork in water.An advantage over terrestrial as it provides a greater support for the organism that air.Water not only helps hold the organism up but can also assist in maintaining their shape (jellyfish) | Air offers some ...view middle of the document...
| Oxygen & carbon dioxide dissolve in water. Where water is in close contact with air both of these gasses are readily available. These gases are most abundant in cases where water is turbulent (i.e river rapids)As water depth increases the gases decreaseIf you boil water the bubbling shows the gases escaping from the water. Therefore there are less of these gases in warmer water i.e tropical seas.The variety of life found in these tropical areas shows that there is enough of these gases. | 20 % of air is oxygen therefore it is very abundant on land (except at high altitudes)Much less air is carbon dioxide (0.03%) therefore it is less abundant however it provides enough for photosynthesis. |
Diffusion of gases: | In order for diffusion into a cell to take place the gas must dissolve in water. This is why any surface used for gas exchange must be moist. | Diffusion of gases in 10,000 times faster in air than water.An advantage for rapid movement of gasses. |
Availability of water: | Water surrounds the organism but is not as readily available as you may think!!!Fresh water environment: More water enters the cell by osmosis than leaves it.Marine environment: More water leaves the cell by osmosis than enters it.See fig 1.5.1 P23 & Unit 2.5 P79-84 | Water is quickly lost through evaporation & constantly needs to be replaced. |
Availability of ions: (salts) | Ions are available in abundance. Convection...