ICSE 6 Biology Habitats Basic

1.0 Habitat and Adaptation

Every living organism has a "home" where it finds food, water, air, and shelter. To survive in these homes, organisms must change or develop special features. This is the story of how life fits perfectly into its surroundings.

Key Terms

Habitat: The natural environment or place where an organism lives and grows.

Adaptation: The presence of specific features or habits which enable an organism to live naturally in its habitat.

Components of a Habitat:

A habitat is made up of two main parts:

• Biotic Components: The living parts like plants, animals, and microorganisms.
• Abiotic Components: The non-living parts like sunlight, air, water, soil, and temperature.

Main Types of Habitats:

• 1. Terrestrial Habitats: Plants and animals that live on land.
  Sub-types: Deserts, Mountains, Grasslands, Forests.
• 2. Aquatic Habitats: Plants and animals that live in water.
  Sub-types: Marine (Oceans/Seas) and Freshwater (Rivers/Lakes).

[IMAGE: Illustration showing Biotic and Abiotic components in an ecosystem]

Fig: Components of a Habitat

⚠️ Important Term: Acclimatisation

Don't confuse Adaptation with Acclimatisation. Adaptation happens over thousands of years (like a camel's hump), while acclimatisation is a short-term change (like your body adjusting to cold weather when you visit a hill station).

💡 Did You Know?

The Arctic Tern holds the record for the longest migration. It travels from the Arctic to the Antarctic and back every year—a round trip of about 70,000 km—just to stay in a comfortable habitat!

2.0 Adaptations in Terrestrial Habitats

Life on land presents extreme challenges—from the scorching heat of the desert to the freezing winds of the mountains. Plants and animals have evolved unique "survival kits" to thrive in these conditions.

1. The Desert Habitat (Xeric)

Deserts are dry with very little water. Adaptations focus on Water Conservation.

Plants (Xerophytes):

• Leaves are reduced to spines to prevent water loss (transpiration).
• Photosynthesis is carried out by the green, fleshy stem which also stores water.
• Roots go very deep into the soil to find water.

Animals (e.g., Camel):

• Long eyelashes and nostrils that can close to protect against blowing sand.
• Padded feet for walking easily on hot sand.
• Can drink a large amount of water at once and survive for days without it.

2. The Mountain Habitat

These regions are normally very cold and windy. Snowfall occurs in winter.

Plants:

• Trees are cone-shaped with sloping branches so snow slides off easily.
• Leaves are needle-like to withstand the cold and wind.

Animals (e.g., Snow Leopard, Yak):

• Thick fur or skin to protect against the extreme cold.
• Yaks have long hair to keep them warm.
• Mountain goats have strong hooves for running up rocky slopes.

Fig: Plant Adaptations in Extreme Terrestrial Habitats

⚠️ Exam Confusion Alert:

A common mistake is thinking a camel's hump stores water. It actually stores fat, which provides energy when food is scarce. Water is stored in the bloodstream and specialized cells!

💡 Did You Know?

Desert rats and snakes don't even need to drink water! They stay in deep burrows during the day to keep cool and get all the moisture they need from the seeds or animals they eat.

3.0 Adaptations in Aquatic Habitats

Water is a much denser medium than air. Organisms living in oceans (marine) or ponds (freshwater) have evolved to move efficiently through water, breathe dissolved oxygen, and handle the lack of intense sunlight in deep areas.

1. Oceans and Seas (Marine Habitat)

Marine animals face the challenge of salt water and high pressure.

Animals (Fish, Squids, etc.):

• Most have a streamlined body (tapered at both ends) to reduce friction while swimming.
• Use Gills to breathe oxygen dissolved in water.
• Have fins and tails for movement and maintaining balance.
• Animals like squids and octopuses stay deeper and catch prey that moves towards them; they move by making their bodies streamlined only when needed.

2. Ponds and Lakes (Freshwater Habitat)

In stagnant or slow-moving water, plants have very different structures compared to land plants.

Aquatic Plants (Hydrophytes):

• Roots: Very small or reduced, as their main job is just to hold the plant in place, not to absorb water (water is everywhere!).
• Stems: Long, hollow, and light so they can float up to the surface to get sunlight.
• Leaves: In floating plants (like Lotus), leaves are broad with a waxy coating to prevent rotting. In submerged plants (like Hydrilla), leaves are ribbon-like to bend with the water current.

Fig: Morphological Adaptations in Aquatic Life

⚠️ Important Distinction: Gills vs. Blowholes

Not all sea animals have gills! Whales and dolphins are mammals; they have lungs and breathe air through blowholes (nostrils) located on the upper parts of their heads. They must come to the surface periodically to breathe.

💡 Did You Know?

Frogs are amphibians, meaning they have a dual habitat. They have webbed feet to swim in water and strong back legs for leaping on land. They can even breathe through their moist skin when underwater!