The Living Organisms: Characteristics and Habitat

Broad classification of Habitat

• Terrestrial: Related to Land e.g., forests, grasslands, deserts, coastal and mountain regions.
• Aquatic: Related to water e.g., Lakes, rivers, and oceans.

Components of Habitat

• Biotic (living): Plants, animals, and microorganisms.
• Abiotic (Non-living): Rocks, soil, air, water, light, and temperature.

The presence of specific features and habits, which enable an organism to live in a particular habitat, is called Adaptation. Those organisms which cannot adapt to changes die, and only the adapted ones survive i.e., "Survival of the fittest."

Some Terrestrial Habitats and Adaptations

1. Deserts: Organisms need adaptations to cope with issues such as Heat and water scarcity.
   • Camels:
     • Long legs keep body away from the hot sand.
     • Excrete small amount of urine, dung is dry, and they do not sweat.
   • Rats and Snakes:
     • Stay in deep burrows in the sand.
     • Come out only during the night when it is cooler.
   • Plants:
     • Leaves are either absent, very small, or they are in the form of spines.
     • Photosynthesis is usually carried out by the stems. E.g., Cactus etc.
     • The stem is also covered with a thick waxy layer to retain water in the tissues.
     • Succulents have parts that are thickened, fleshy, and engorged to store water.
     • Roots go very deep into the soil for absorbing water.

2. Mountainous regions: Organisms also need adaptations to cope with very cold and windy environments including Snowfall.
   • Trees:
     • Cone-shaped and have sloping branches.
     • Needle-like leaves to slide off rainwater and snow easily.
   • Animals:
     • Thick skin or fur e.g., Yaks, Snow leopard etc.
     • Mountain goat has strong hooves for running up the rocky slopes.

3. Grasslands
   • Lion:
     • Long claws to catch prey (animals to eat).
     • Its light brown colour to hide in dry grasslands.
     • The eyes in front of the face to detect prey.
   • Deer:
     • Strong teeth for chewing hard plant stems.
     • Long ears to hear movements of predators (like lion etc).
     • Eyes on the side of its head to look in all directions for danger.
     • Speed of the deer helps them to run away from the predators.

Some Aquatic Habitats and Adaptations

1. In Oceans:
   • Sea animals have streamlined bodies to flow easily.
   • Animals like squids and octopus which do not have streamlined body stay deeper in the ocean.
   • Animals usually have gills to use oxygen dissolved in water.
   • Dolphins and whales that do not have gills breathe in air through nostrils or blowholes. They come out to the surface to breathe in air.

2. In ponds and lakes:
   • Roots fixed in the soil below the water to hold the plant.
   • Stems are long, hollow, and light to grow up to the surface of the water.
   • Leaves and flowers float on the surface of the water.
   • Submerged plants have narrow and thin ribbon-like leaves which can bend in the flowing water.
   • Frogs have webbed feet which help them swim in the water.

Characteristics of Organisms

Living things have certain common characteristics: they need food; they respire and, excrete, respond to their environment, reproduce, grow, and show movement.

• Food: Gives organisms the energy needed for them to grow and sustain life processes.
• Growth: They are different stages of growth. e.g., New-born human baby to Adult
• Breathing: Breathing is part of a process called Respiration. It is through respiration that the body finally obtains energy from the food.
  • Earthworms breathe through their skin.
  • Fish have gills for using oxygen dissolved in water.
  • Plant leaves take in air through tiny pores.
• Respond to Environment: 
  • Changes in our surroundings that make us respond are called stimuli. e.g., hiding of cockroaches in the light etc.
  • Flowers of plants either bloom at night or close after sunset.
  • Plants like Mimosa, commonly known as ‘touch-me-not’, leaves close or fold when someone touches it.

• Excretion: The process of getting rid of wastes by organisms is known as Excretion. 
• Reproduce: 
  • Animals produce their young ones through eggs or give birth to the young ones.
  • Plants produce seeds, which can germinate and grow into new plants.
  • Some Plants reproduce through parts other than seeds. e.g., a part of a potato with a bud grows into a plant. Plants also reproduce through cuttings like Rose.

In general, something that is living may have all the above characteristics while non-living things may not show all these characteristics at the same time.

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