Life running short of water

In Chapter 2, we saw that there were a number of terrestrial environments in which the availability of water was likely to be a problem. Organisms have two main responses to situations where water is in short supply and is only sporadically available. The first is a suite of capacity adaptations. The organism taps the sources of water that are available, such as the tenebrionid beetles which collect moisture from the fog that forms in the Namib Desert or plants which send out long roots to seek water. Some plants, such as cacti, store water to use during dry periods. Plants and animals have adaptations which conserve the water within their tissues. They have a waxy cuticle or skin and a covering of hairs or spines to restrict water loss. Animals may produce a concentrated urine and dry faeces and recover water from their breath. The second response to a lack of water is to lie dormant until water becomes available again.

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