Different modes of nutrition are:

Let's understand each mode in detail.

Autotrophic Nutrition:

Definition 

The mode of nutrition in which organisms prepare their own food from simple raw materials is called autotrophic nutrition.

These organisms are called autotrophs.

Features:

1. Plants are the only autotrophs.
2. They can prepare their own food by photosynthesis.
3. They use simple substances like water, carbon dioxide, sunlight & minerals to prepare their food.

To Remember:

1. Plants can prepare their own food.
2. Hence they are called autotrophs.

Heterotrophic Nutrition

Definition:

The mode of nutrition in which an organism obtains food from other organisms is called as heterotrophic nutrition.

The organisms are called heterotrophs.

Features:

1. Heterotrophs cannot prepare their own food.
2. Animals & humans get their food from plants or animals that eat plants.
3. Thus, heterotrophs are directly or indirectly dependent on plants.
4. Some plants are also heterotrophs as they cannot prepare their own food.

There are four types of heterotrophic plants.

1. Parasitic plants
2. Insectivorous plants
3. Saprophytic plants
4. Symbiotic plants

Let's understand each type in detail.

To remember:

1. Heterotrophs cannot make their own food.
2. They depend on plants or other animals for their nutrition.
3. Some plants are also heterotrophs.

Parasitic plants

Plants which derive their food & nutrition from other plants are called as parasitic plants.

Diagram:

Features:

1. These plants cannot prepare their own food.
2.  In the above diagram, there is a yellow wiry branched structure climbing around the stem of another plant.
3. This is a parasitic plant called Cuscuta (Amarbel).
4. It does not have chlorophyll.
5. It  takes readymade food from the plant on which it attaches itself.
6. The plant on which it climbs is called the host.
7. It deprives the host of valuable nutrients.
8. Hence it is called a parasite.

To remember:

1. Parasitic plants don't have chlorophyll.
2. They can't prepare their own food.
3. They take food from the host plant.

Insectivorous plants

Insectivorous plant trap & eat insects to fulfill their nutrition & energy requirements.

Diagram:

Features:

1. These plants have green leaves with chlorophyll.
2. They fulfill their carbohydrate requirement through photosynthesis.
3. They grow in damp & humid areas with soil deficient of nitrogen.
4. To fulfill this requirement of nitrogen, their leaves are modified to trap insects.
5. Hence, they are carnivorous & partially heterotrophic plants.
6. Eg: Pitcher plant, venus flytrap, bladderwort. 

Features of pitcher plant:

1. It's leaf is modified to a pitcher or jug like structure.
2. The apex of the leaf forms a lid which can open & close the mouth of the pitcher.
3. The pitcher has hair that are directed downwards.
4. When an insect gets trapped in the pitcher, the lid closes. 
5. The insect gets entangled in the hair.
6. The insect is digested by the digestive juices secreted in the pitcher & its nutrients are absorbed. 

To remember:

1. Insectivorous plants are carnivorous plants.
2. They prepare their own food & eat insects too.
3. They grow in soil deficient of nitrogen.

Saprotrophic Nutrition

In saprotrophic mode of nutrition, organisms derive their nutrients from dead & decaying matter.

the organisms are called as saprotrophs or fungi.

Diagram:

Features:

1. Mushroom are fluffy umbrella-like patches growing in moist soil or on rotting wood during the rainy season.
2. Bread mould grows & absorbs the nutrients from moist bread .
3. These are fungi that grow on pickles, leather, clothes & other articles that are left in hot and humid weather.
4. During the rainy season they spoil many things.
5. These fungi reproduce through spores that are present in the air.
6. When they land on wet & warm things they germinate & grow.

Benefits:

Saprophytes play a important role in balancing the ecosystem by breaking down complex organic materials & recycling nutrients back into the soil.

To remember:

1. Saprotrophs are fungi.
2. They grow on dead decaying matter in hot & humid weather.

Symbiosis:

Symbiosis is a relationship between some organisms that live together & share shelter & nutrients.

This type of nutrition is called symbiotic nutrition.

Diagram:

Features:

1. This is a very different type of mode of nutrition.
2. In symbiosis, organisms live together & help each other by mutually sharing shelter & nutrients. 
3. In lichens, an alga & fungus live together.
4. The fungus provides the alga with shelter, water & minerals.
5. The alga that has chlorophyll to prepare food & provide it to the fungus.
6. Similarly certain fungi are present in the roots of the plants.
7. They provide water & nutrients to the plant & the plant prepares food and provides it to the fungus.
8. One more example is rhizobium bacteria that live in root nodules of leguminous plants. For details click here.

To remember:

1. Symbiosis is a partnership between organisms to live together.
2. They do this by sharing shelter & nutrients.
3. Eg: lichens, rhizobium bacteria.