ANAND CLASSES study material and notes to learn the key differences between autotrophic and heterotrophic nutrition, including definitions, processes, examples for class 10 Science (Biology) Subject.
Introduction
Nutrition is the process by which living organisms obtain and utilize food for their growth, maintenance, and energy requirements. Based on the mode of obtaining food, nutrition can be classified into Autotrophic Nutrition and Heterotrophic Nutrition.
Autotrophic Nutrition
Autotrophic nutrition is a mode of nutrition in which organisms prepare their own food using simple inorganic substances like carbon dioxide and water in the presence of sunlight and chlorophyll.
Examples:
- Green Plants (e.g., Mango tree, Grass, Algae)
- Some Bacteria (e.g., Cyanobacteria, Sulfur bacteria)
Characteristics:
- Organisms synthesize their own food.
- Requires sunlight and chlorophyll (in most cases).
- Involves photosynthesis or chemosynthesis.
- Occurs in green plants, algae, and some bacteria.
- Stores energy in the form of carbohydrates (glucose).
Process of Photosynthesis (in plants):
- Absorption of Light Energy – Chlorophyll absorbs sunlight.
- Splitting of Water Molecules – Water is broken down into oxygen and hydrogen.
- Conversion of Energy – Light energy is converted into chemical energy.
- Formation of Glucose – Carbon dioxide is utilized to form glucose.
Chemical Equation:
$$6CO_2 + 6H_2O \xrightarrow{Sunlight} C_6H_{12}O_6 + 6O_2$$
Heterotrophic Nutrition
Heterotrophic nutrition is a mode of nutrition in which organisms depend on other organisms for food.
Examples:
- Animals (e.g., Humans, Cows, Lions)
- Fungi (e.g., Mushrooms, Yeast)
- Some Bacteria (e.g., Lactobacillus)
Characteristics:
- Organisms cannot prepare their own food.
- Depend on autotrophs or other heterotrophs for nutrition.
- Can be further divided into different types:
- Holozoic Nutrition – Organisms consume solid food (e.g., Humans, Lions).
- Saprotrophic Nutrition – Organisms feed on dead and decaying matter (e.g., Fungi, Bacteria).
- Parasitic Nutrition – Organisms live on or inside another organism and derive nutrition (e.g., Tapeworms, Mistletoe).
Process of Holozoic Nutrition:
- Ingestion – Intake of food.
- Digestion – Breakdown of complex food into simpler substances.
- Absorption – Nutrients are absorbed into the bloodstream.
- Assimilation – Utilization of absorbed nutrients.
- Egestion – Removal of undigested food.
Detailed Differences Between Autotrophic and Heterotrophic Nutrition
| Feature | Autotrophic Nutrition | Heterotrophic Nutrition |
|---|---|---|
| Definition | Mode of nutrition in which organisms prepare their own food using inorganic substances and energy sources like sunlight or chemicals. | Mode of nutrition in which organisms depend on other organisms (plants or animals) for their food requirements. |
| Energy Source | Sunlight (photosynthesis) or chemical energy (chemosynthesis). | Organic matter from plants, animals, or decaying substances. |
| Food Production | Organisms can synthesize their own food. | Organisms cannot synthesize their own food and rely on external sources. |
| Chlorophyll Requirement | Requires chlorophyll for photosynthesis. | Does not require chlorophyll. |
| Types of Organisms | Found in green plants, algae, and some bacteria (e.g., Cyanobacteria). | Found in animals, fungi, and some bacteria (e.g., Lactobacillus). |
| Process Involved | Photosynthesis (in plants) or chemosynthesis (in some bacteria). | Ingestion, digestion, absorption, assimilation, and egestion. |
| Dependency | Does not depend on other organisms for food. | Dependent on autotrophs or other heterotrophs for survival. |
| Examples | Plants (e.g., Mango tree, Algae), Cyanobacteria. | Animals (e.g., Humans, Cow), Fungi (e.g., Mushroom), Parasites (e.g., Tapeworm). |
| Role in the Ecosystem | Producers – form the base of the food chain by producing organic matter. | Consumers and decomposers – maintain balance by consuming plants/animals or decomposing dead matter. |
| Storage of Energy | Stores energy in the form of carbohydrates (glucose). | Energy is obtained by consuming stored food from other sources. |
| Environmental Impact | Helps in oxygen production and carbon dioxide absorption. | Contributes to decomposition, nutrient cycling, and maintaining population balance. |
Conceptual Questions with Answers
Q1. Why are green plants called autotrophs?
- Green plants are called autotrophs because they synthesize their own food using sunlight, water, and carbon dioxide through the process of photosynthesis.
Q2. Why do heterotrophs depend on autotrophs for food?
- Heterotrophs depend on autotrophs directly or indirectly because they cannot prepare their own food. They either consume plants (herbivores) or animals that have fed on plants (carnivores and omnivores).
Q3. What are the main differences between autotrophic and heterotrophic nutrition?
- The main differences are the mode of obtaining food, dependency on other organisms, and energy sources used for food synthesis.
FAQs
Q1. Can any animal exhibit autotrophic nutrition?
- No, animals lack chlorophyll and cannot perform photosynthesis. They are all heterotrophic.
Q2. Do fungi show autotrophic nutrition?
- No, fungi exhibit saprotrophic nutrition by feeding on decaying organic matter.
Q3. What is the significance of autotrophic nutrition in the ecosystem?
- Autotrophs form the base of the food chain and provide energy to all other organisms.
Do You Know?
- Some bacteria use chemosynthesis instead of photosynthesis to make food.
- Carnivorous plants like Venus flytrap show both autotrophic and heterotrophic nutrition.
- Deep-sea hydrothermal vent bacteria use sulfur compounds for energy instead of sunlight.
Quick Revision Points
- Autotrophic Nutrition: Organisms make their own food (e.g., Plants, Algae).
- Heterotrophic Nutrition: Organisms depend on others for food (e.g., Animals, Fungi).
- Photosynthesis: Process by which plants prepare food using sunlight, CO₂, and water.
- Heterotrophic Types: Holozoic, Saprotrophic, Parasitic.
- Autotrophs are primary producers in the food chain.
- Heterotrophs include consumers and decomposers.
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