life processes
Nutrition, respiration, excretion, transportation, reproduction, sensitivity and growth are some of the processes that help the living being to sustain. These processes that are common to all living beings are called as the life processes.
Energy for life processes
All living organisms require energy to perform various activities. This energy is derived from the food they eat. Thus food is a kind of fuel which provides energy to all the living organisms. Food contains several components called as nutrients. Based on their functions nutrients are divided into three types.
(1) Energy giving nutrients - Carbohydrates, fats(2) Body building nutrients - Proteins(3) Protective and regulating nutrients - Vitamins and minerals
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Nutrition, respiration, excretion, transportation, reproduction, sensitivity and growth are some of the processes that help the living being to sustain. These processes that are common to all living beings are called as the life processes.
Energy for life processes
All living organisms require energy to perform various activities. This energy is derived from the food they eat. Thus food is a kind of fuel which provides energy to all the living organisms. Food contains several components called as nutrients. Based on their functions nutrients are divided into three types.
(1) Energy giving nutrients - Carbohydrates, fats(2) Body building nutrients - Proteins(3) Protective and regulating nutrients - Vitamins and minerals
Heterotrophic nutrition
Organisms that depend on other organisms for their food are heterotrophic organisms. All animals and fungi are heterotrophs. Different organisms use different strategis to obtain food depending upon their body design, organization, functioning and also availability of food material.
e. g.
- Fungi like yeast, mushrooms and some carnivorous plants break down the food material into simple substances outside the body and then absorb it.
- Some organisms take in whole food and then break it down to simple substances inside their bodies and then absorb it. E.g. human being, cat, cow, etc.
- Some animals and plants derive nutrition from other plants or animals without killing them but during the process they harm the host plant or animal. E.g . cascuta,ticks, lice, leeches, tapeworms etc
Nutrition in human beings
All the processes involved in nutrition in human beings take place by association of digestive organs called digestive system. The digestive system includes alimentary canal and the digestive glands.
(1) Mouth:
The alimentary canal beings with mouth. We eat a variety of food items which have to pass through the same digestive tract. Naturally the food has to be processed to generate particles with small size.
Can you tell which organs of the body are involved in breaking the large food particles into smaller ones?
Such crushed food is wetted with saliva secreted by the saliva glands so the food can smoothly pass through the soft lining of the alimentary canal. The food that we take is of complex nature. It is converted into simpler molecules with the help of biological catalysts called as enzymes. Enzyme salivary amylase breaks down starch into a simple sugar maltose. Thus digestion starts in the mouth itself.
(2) Stomach:
The partly digestion food goes down through the oesophagus into a ‘J’ shaped stomach placed on the left side of the abdomen. The food is pushed forward in the canal due to rhythmic contraction and relaxation of the muscles of the canal called as peristaltic movement
Digestive glands
liver
villi
stomach
Excretion in human beings
the excretory system in human beings includes a pair of kidney, a pair of ureters, urinary bladder and urethra. kidneys remove the waste products from the blood and urine.
