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What is an adaptation?
An adaptation is a characteristic of an organism which makes it well-suited to survival in it's environment
What are the three general kinds of adaptations?
A water balance problem exists in aquatic animals whose cells are hypertonic with their surrounding environment because they constantly ______ water via osmosis?
A water balance problem exists in aquatic animals whose cells are hypotonic with their surrounding environment because they constantly
______ water via osmosis?
How can aquatic animals maintain their water balance?
With physiological adaptations - osmoregulation
Are the cells of freshwater fish hypertonic or hypotonic to their surrounding environment? And do freshwater fish gain or lose water via osmosis?
How do fresh-water fish combat this problem?
- By excreting large volumes of very dilute urine
- Posessing many, large kidneys that are very efficient at reabsorbing minerals
- Actively absorbing salt through their chloride secretory cells
Are the cells of salt-water fish hypertonic or hypotonic to their surrounding environment? And do salt-water fish gain or lose water via osmosis?
How do salt-water fish combat this problem?
- By excreting small volumes of concentrated urine
- Posesses few, small kidneys that are inefficient at reabsorbing minerals
- Actively excretes salt through their chloride secretory cells
What must some fish who migrate from fresh water to the sea and back again, or vice versa, be able to do in order to maintain their water concentration?
Osmoregulate in both environments
What is the advantage of the mirgatory behaviour of some fish?
These fish are able to exploit a wider range of habitat than those wich cannot alter osmoregulation
What are the physiological adaptations of the desert rat that enable it to conserve water?
- It has dry mouth and nasal passages which reduce water loss by evaporation
- It does not sweat
- It's large intestine is very efficient at reabsorbing water from waste material so faeces are very dry
- It has very long loops of Henle and produces high levels of anti-diruetic hormone (ADH) in the blood which increases reabsorption of water by the kidneys
What are the behavioural adaptations of the desert rat that enable it to conserve water?
- It it nocurnal - active at night when it is cool
- It is inactive during the day
- It stays inside it's underground burrow during the day where it is cooler and more humid, reducing water loss