The things that move, grow, breathe, need food, feel changes, and reproduce are called living things. The main characteristics of living things are:
- All living things need food.
- All living things grow.
- All living things respire (breathe).
- All living things respond to stimuli. Changes in our surroundings which make us responf to them are called stimuli.
- All living things reproduce their own kind.
- All living organisms excrete. Excretion is a process by which living organisms get rid of the wastes.
- All living things move.
The things that do not move, grow, breathe, need food, feel changes or reproduce are called non-living things.
An organism, in simple words, is an individual living thing. From microscopic bacteria to an elephant, all living forms are organisms.
ORGANISMS AND THEIR SURROUNDINGS: HABITAT AND ADAPTATION
The process of change by which an organism becomes better suited to its environment is called adaptation.
A habitat is the natural environment and surroundings in which a particular organism lives. The organisms depend on their habitat for their food, water, shelter and other needs.
There are different types of habitats. Some of them are as follows:
1. Terrestrial habitats: The plants and animals that live on land are said to live in terrestrial habitats. For e.g.: forests, grasslands, deserts, etc. Deserts are habitats which do not have much water so naturally the organisms in the desert need to be able to survive without water.
2. Aquatic habitats: The plants and animals that live in water are said to live in aquatic habitats. For e.g.: Ponds, swamps, lakes, oceans, etc.
Some terrestrial habitats:
Deserts: Desert animals like rats and snakes do not have long legs so to stay away from the intense heat, they stay in burrows deep in the sand. Animals like camels store water in their body to survive the lack of availability of water. Desert plants lose very little water through transpiration. The leaves in desert plants are either absent, very small or in the shape of spines. This helps is reducing loss of water from the leaves.
Mountain Regions: Mountain regions are very cold and windy. Animals living in the mountain regions have thick skin or fur to protect them from the cold. The plants that grow in the mountain regions are normally cone shaped and have sloping branches. This helps the rainwater and snow to slide off easily.
Grasslands: Grasslands are the areas where the plants are dominated by grasses. Animals that live in the grasslands range from lion (a predator) to a deer (a prey).
Some aquatic habitats:
Oceans: Many other sea animals have streamlined bodies to help them move easily in water. There are some sea animals like dolphins and whales that do not have gills. They breathe in air through nostrils or blowholes that are located on the upper parts of their heads. This allows them to breathe in air when they swim near the surface of water. The plants in the oceans and seas grow on the ocean floor.
Ponds and lakes: Some plants have their roots fixed in the soil below water. In aquatic plants, roots are much reduced in size and their main function is to hold the plant in place.
BIOTIC AND ABIOTIC THINGS AROUND US
Biotic components: The living things in a habitat are called its biotic components. E.g.: Plants, animals, etc.
Abiotic components: The non-living things in a habitat are called its abiotic components. E.g.: Air, water, soil, etc.