3.1 Hemeostasis in Living Things - Homeostasis in Animals and Plants

3.1 Hemeostasis in Living Things 
Homeostasis in Animals

■ Homeostasis also occurs in animals.

■ The examples of animal homeostasis are as follows.

• Cats' skin is covered in fur, so cats cannot remove much heat through sweating. Cats have the most sweat glands on their paw pads, but paws have too small surface area to do much cooling. Therefore, cats always lick their fur. When the saliva evaporates, it provides cooling effect, much like sweat would do. This helps to reduce the body temperature efficiently.
• Reptiles like lizards and geckos are cold-blooded animals. In a cold surrounding, the activities and movement of their body will be slower, the metabolism rate will also decrease and the muscles will w to reduce the heat loss. In a hot surrounding, the movement is faster, the heart beats faster and the metabolism rate increases.
• Snails produce mucus that coats their body and reduces evaporation of water from their skin surface.  Snails also seek out shelter in damp places.
• Dogs cannot remove much heat through sweating because they only have sweat glands on the nose and paw pads. Therefore, they always stick out their tongue which allows saliva to evaporate from the tongue. This reduces the body temperature.
• Bees can reduce the loss of water through spiracles on their body by closing the spiracles between two breathing movements.

Homeostasis in Plants
■ Homeostasis helps plants to regulate their water content when the surrounding or weather changes.
■ Homeostasis allows plant cells to store sufficient water. This could help the plants to prevent withering or death during droughts.
■ Plants lose water to the surrounding through a process called transpiration.

Transpíration
Transpiration is the process of losing water from the surface of plant leaves in the form of water vapour to the atmosphere through stomata.

■ Transpiration helps in cooling down the plants when water gets evaporated.
■ At the same time, transpiration causes movement of water to occur in plants, from roots to leaves. This helps to transport water and minerals in plants.


Stoma
A stoma is a tiny pore on the surface of leaf and is used for gas exchange and absorption of water vapour.

■ A stoma is a tiny pore between a pair of cells called guard cells on the leaf.
■ Guard cells control the opening and closing of the stoma.
■ The opening of stoma will increase the transpiration rate and the rate of water absorption, while the closing of stoma will reduce the water loss.


The Importance of Homeostasis to Humans and Living Things
Audio: Importance of Homeostasis to Humans and Living Things

■ Importance of Homeostasis to Humans and Living things.

• Prepares an optimum internal environment so that all life processes in an organism will function properly.
• Maintains a stable and balanced internal environment despite the changes in the external environment.
• Enables organisms to live in a wide range of habitat.
• Allows the reactions catalysed by enzymes to occur at an optimal rate.
• Controls the metabolism rate of an organism to be efficient according to the body's needs.

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