The Living Organisms: Characteristics And Habitats | Class 6 Science Chapter Notes

Key Terms and Definitions

Habitat

The natural home or environment where a plant or animal lives, which provides food, water, air, and shelter.

Adaptation

The presence of specific body features or certain habits which enable a plant or an animal to live in its particular habitat.

Biotic Components

The living things in a habitat, such as plants, animals, fungi, and bacteria.

Abiotic Components

The non-living things in a habitat, such as rocks, soil, air, water, sunlight, and temperature.

Acclimatisation

Small, short-term adjustments made by an organism to overcome changes in its surroundings. This happens over a short period.

Excretion

The process by which living organisms get rid of waste products from their bodies.

Respiration

The process where organisms take in oxygen and use it to release energy from food, releasing carbon dioxide as a waste product.

Stimuli

Changes in the environment that make an organism respond or react. (Singular: Stimulus)

Photosynthesis

The process used by plants to make their own food using sunlight, water, and carbon dioxide.

Understanding Adaptation in Different Habitats

Adaptation is the key to survival. It's not a choice an animal makes, but a result of gradual changes over many, many generations. These changes help an organism to live comfortably, find food, and protect itself in its specific habitat. For example, in terrestrial (land) habitats like deserts, a camel has long eyelashes to protect its eyes from sand, a hump to store fat for energy, and can drink large amounts of water at once. A cactus has spines instead of leaves to reduce water loss. In aquatic (water) habitats, fish have a streamlined body to cut through water easily and gills to breathe oxygen dissolved in the water. In cold mountain regions, animals like the yak have thick fur to stay warm, and trees are cone-shaped so snow can slide off easily. These features are all examples of adaptation.

Biotic vs. Abiotic Components

Must-Remember Key Points

• All living things need food, grow, respire, respond to stimuli, excrete, reproduce, and move.
• A habitat provides an organism with everything it needs: food, water, air, and shelter.
• The two major types of habitats are Terrestrial (land-based) and Aquatic (water-based).
• Deserts, mountains, and grasslands are examples of terrestrial habitats.
• Oceans, ponds, and lakes are examples of aquatic habitats.
• Adaptations are permanent features developed over a long time, while acclimatisation is a temporary adjustment.
• The living parts of a habitat are its biotic components.
• The non-living parts like sunlight, water, and soil are its abiotic components.
• Plants also respond to stimuli, for example, the 'touch-me-not' plant closes its leaves when touched.
• Reproduction is essential for the continuation of a species.

Characteristics of Living Organisms

Exam Tip: Adaptation vs. Acclimatisation

Examiners love to test the difference between Adaptation and Acclimatisation. Remember this simple trick:

• Adaptation is a All-the-time, permanent feature (like a polar bear's fur). It takes thousands of years to develop.
• Acclimatisation is a change for a certain time, it's temporary (like you feeling breathless at a high altitude and then getting used to it in a few days).

If a question asks about a feature an entire species has (e.g., gills in fish), it's adaptation. If it's about an individual organism getting used to a new situation (e.g., a trekker on a mountain), it's acclimatisation.

Quick Revision Check

• What are the five abiotic factors essential for living organisms? Air, water, heat (temperature), light (sunlight), and soil.
• Give one adaptation of a plant living in a desert. Cactus plants have spines instead of leaves to reduce water loss through transpiration, and a waxy stem to store water.
• Is a fallen leaf a biotic or abiotic component? A fallen leaf is a biotic component because it was once part of a living thing (the tree).
• Name the process by which plants make their own food. Photosynthesis.

Frequently Asked Questions

Frequently Asked Questions