Class-6, Science, Chapter:- 09 The Living Organisms & Their Surroundings Notes, NCERT Solutions & Frequently Asked Questions

  Science

Class:-6, Chapter:- 09

The Living Organisms & Their Surroundings

Notes, NCERT Solutions & Frequently Asked Questions

-- Notes --

⭐ Organisms:- An organism is simply defined as any living thing, ranging from microscopic bacteria to large elephants and everything in between.

• Different types of plants and animals are found in different areas. For example deserts have camel and cacti as plants.

• Beaches show coconut trees and crabs.

• Fishes and other marine animals inhabit the sea.

⭐ Difference between living & non-living:- Plants are living things, but they do not appear to move like a dog or a pigeon. 

⧫ On the other hand, a car or a bus can move, yet we consider them as non-living. 

⧫ So there are certain characteristics that differentiate living from nonliving:-

• Living beings are made of cells.

• Living beings obtain and use energy.

• Living beings grow and develop.

• Living beings reproduce.

• Living beings adapt to their environment

• Living beings respond to their environment or stimuli.

⭐ Characteristics of Living Organisms:-

a) Nutrition:- The process by which animals obtain food and utilize it for all the activities is called as nutrition.

• Every organism requires nutrition for obtaining energy.

b) Growth:- All living organisms grow and exhibit growth in different ways.

• Their body cells divide and grow and thus overall growth is attained.

c) Respiration:- Respiration is necessary for all living organisms. 

• It is through respiration that the body finally obtains energy from the food it takes.

• Some animals may have different mechanisms for the exchange of gases, which is a part of the respiration process.

• Earthworms breathe through their skin and fish have gills for using oxygen dissolved in water.

• In humans, we respire by breathing in oxygen breathing out the carbon dioxide.

d) Response to Stimulus:- Changes in our surroundings that makes us respond to them are called stimuli.

• All living beings react to changes in their surroundings.

• E.g. In response to increased temperature in summer, we use fans to cool our homes.

e) Excretion:- All living things take food. Not all the food that is eaten is really used, only a part of it is utilised by the body.

• Unused/remaining food becomes waste and needs to be excreted.

• Our body also produces some wastes, like urea, in other life processes.

• Living organisms get rid of all this waste material and the process is known as excretion.

f) Reproduction:- All living organisms give rise to a new organism of their own kind, by a process called reproduction.

• The mode of reproduction may be different, in different animals and plants.

• Some animals produce their young ones through eggs, called Oviparous animals. 

• Some animals give birth to the young ones, called Viviparous animals.

• Plants produce seeds which germinate into new plants.

• Some plants also reproduce through parts other than seeds. E.g.- a part of a potato with a bud, grows into a new plant

g) Movement:- Animals move from one place to another and also show other body movements.

• Plants are generally anchored in the soil so they do not move from one place to another.

• However, various substances like water, minerals and the food synthesised by the plants move from one part to other.

• Plants also show other kinds of movement like the opening and closing of flower buds.

h) Cellular Structure:- Cells constitute plants and animal bodies.

• Cells are organised in various ways in different organisms.

• They help in carrying out various functions like nutrition, respiration, etc.

• Cells are called structural and functional unit of all living organisms.

i) Adaptation:- The presence of specific features or certain habits, which enable a plant or an animal to live in its surroundings, is called adaptation.

• Different animals are adapted to their surroundings in different ways.

• For example fishes have slippery scales on their bodies. These scales protect the fish and also help in easy movement through water.

⭐ Habitats:- The different surroundings or areas have different organisms that live in.

• For example the deserts have camels, the mountains have goats and yak.

• The surrounding where living organisms survive is known as habitat.

• The organisms depend on their habitat for their food, water, air, shelter and other needs.

• Habitat means a dwelling place (a home).

• Several kinds of plants and animals may share the same habitat.

⭐ Components of Habitats:-

a) Biotic Components:- The living components ( plants, animals & microorganisms) of a habitat are called biotic components. 

b) Abiotic Components:- The non-living components (rocks, soil, air, water, light &  temperature) of a habitat are called as abiotic components.

• Light:- The sunlight is essential for the survival of all the animals & plants as it affects growth, flowering, seed germination and in many other ways in plants & animals. 

• Temperature:- Temperature regulates growth, movement, reproduction, morphology and other aspects of life.

- Animals living in hot areas (snakes, desert rats & lizards) are not able to get sufficient water so they have thick skin & do not sweat.

- Desert animals (camel) have long legs. Long legs help them to lift their body above the ground. Thus, they are able to avoid direct contact with the hot ground.

• Water:- All living organisms need water for their survival.

- Aquatic plants:- Plants growing in water have poorly developed root system & air filled cavities are found inside the body to make them spongy and buoyant. Leaves in submerged plants are thin & narrow; while in floating plants, leaves are big & flat with waxy coating.

- Desert plants:- Plants growing in deserts have well-developed root systems. Stem is succulent and spongy which help in storage of water. It is also green & performs photosynthesis. Stomata are less in number. Leaves are either very small or converted into spines.

- Fish:- They have tapering ends, slippery scales which help in swimming & gills for respiration.

⭐ Types of Habitats:- 

a)  Terrestrial Habitats:- The plants and animals that live on land are said to live in terrestrial habitats.

• E.g.- forests, grasslands, deserts, coastal and mountain regions.

b) Aquatic Habitats:- The habitats of plants and animals that live in water are called aquatic habitats.

• E.g.- ponds, swamps, lakes, rivers and oceans.

• Aquatic habitats could be fresh water (river, pond) or marine (sea) or even estuarine (delta of river meeting with the sea).

⭐ Nocturnal animals:- Some animals like bats, cockroaches and owls are called nocturnal as they are active during night.

⭐Stimulus:- The factors like food, water, light, touch, gravitational force, etc., are stimuli to which plants and animals respond.

⭐Life Span:- Each animal lives for a certain period. This period is referred to as life span.

-- NCERT Solutions --

Question 1.- What is a habitat?

Solution:- The place where organisms live is called habitat. Habitat means a dwelling place (a home). The habitat provides food, water, air, shelter and other needs to organisms.

Question 2.- How are cactus adapted to survive in a desert?

Solution:- Adaptation of cactus are as follows:-

• Leaf is replaced by spine to reduce transpiration. 

• Stems carry out photosynthesis. 

• A thick waxy layer surrounds leaf to retain water. 

• Roots of cactus are deeply rooted inside soil to absorb water. 

Question 3.- Fill up the blanks:-

a) The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called _________.

b) The habitats of the plants and animals that live on land are called _____________ habitat.

c) The habitats of plants and animals that live in water are called __________ habitat.

d) Soil, water and air are the _________ factors of a habitat.

e) Changes in our surroundings that make us respond to them, are called ________.

Solution:-

a) Adaptation.

b) Terrestrial.

c) Aquatic. 

d) Abiotic.

e) Stimuli.

Question 4.- Which of the things in the following list are nonliving?

{Plough, Mushroom, Sewing machine, Radio, Boat, Water hyacinth, Earthworm}

Solution:- Plough, Sewing machine, Radio and Boat are nonliving things

Question 5.- Give an example of a non-living thing, which shows any two characteristics of living things.

Solution:- ⧫ For example:- Car 

⧫ Features:- 

   • It can move like living beings. 

   • It needs energy to do work

Question 6.- Which of the non-living things listed below, were once part of a living thing?

{Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber}

Solution:- Butter, Leather, Wool, Cooking oil, Apple and Rubber were once part of a living thing.

Question 7.- List the common characteristics of the living things.

Solution:- Common characteristics of living things are as follows

i) Respiration

ii) Food intake

iii) Respond to stimuli

iv) Excretion

v) Movement

vi) Reproduction

vii) Grow and Die

Question 8.- Explain, why speed is important for survival in the grasslands for animals that live there. (Hint:- There are few trees or places for animals to hide in grasslands habitats.)

Solution:- Speed is important for survival in the grasslands for animals to avoid predation from their predators. For example Tiger eats deer, to survive deer has to run faster than the tiger.

-- Frequently asked Questions --

Question 1.- What is ‘Response to stimuli’?

Solution:- Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus.

Question 2.- What are ‘Biotic Components’?

Solution:- Biotic components include plants, animals, decomposers. Nonliving components include air, water, land.

Question 3.- What are ‘Aquatic habitats’?

Solution:- An aquatic habitat is a habitat in water. It includes areas that are permanently covered by water and surrounding areas that are occasionally covered by water.

- By Durgesh Pandey