All the organisms do not have same mode of nutrition, i.e. different organisms have different methods of obtaining and utilizing food. Based on the mode of nutrition, all the living organisms can be classified in two groups:
- Autotrophic and
The term ‘autotroph’ consists of two words ‘auto’ and ‘troph’. ‘Auto’ means ‘self’ and ‘troph’ means ‘nutrition’. So , in autotrophic mode of nutrition the food is manufactured by the organism itself in the presence of sunlight by taking in raw materials such as carbon dioxide or water from the surrounding All the green plants, blue green algae and autotrophic bacteria have autotrophic mode of nutrition.
Such organisms which can make their own food in the presence of sunlight by taking carbon dioxide and water from their surroundings are called autotrophs. Green plants and autotrophic bacteria are the examples of autotrophs. These organisms contain a green colouring pigment called chlorophyll which is capable of trapping solar energy. This solar energy is then used by plants to synthesize food in the form of starch by combining carbon dioxide and water taken from the surrounding by the process of photosynthesis.
It should be noted that green plants are also called producers because they prepare or produce their own food from carbon dioxide and water by using sunlight.
Test Your Understanding and Answer These Questions:
- What are different modes of nutrition? Explain each by giving one example in each case.
- What do you meant by autotrophs heterotrophs?
- Why green plants are called producers?