2021-22 SCIENCE CH LIVING ORGANISMS AND ITS SURROUNDINGS( NB AND WB EXERCISE)
2021-22 SCIENCE CH LIVING ORGANISMS AND ITS SURROUNDINGS( NB AND WB EXERCISE)
NEW WORDS HW
hibernation
decomposer
stimulus
biotic
abiotic
NEW TERMS
1. Hibernation: a deep winter sleep that helps organisms to survive extreme climatic changes.
2. Decomposer: organisms that break down dead plants and animals
Answer the following questions in short.
a. What do you mean by breathing?
ANS. Living beings get oxygen by taking in or inhaling fresh air and they expel carbon dioxide by giving out or exhaling used air. The process of taking in fresh air and giving out used air is called breathing.
b. How do fish breathe in water?
ANS. Fish take water into their mouth, passing the gills just behind its head on each side. Dissolved oxygen is absorbed from—and carbon dioxide released to—the water, which is then dispelled.
c. What is the main difference between autotrophs and heterotrophs?
ANS. Green plants which prepare their food using the energy from the Sun are called autotrophs.
Animals and non-green plants cannot make their food. They depend on plants for food. Some animals eat other animals to obtain energy. Living organisms that depend on plants and other animals for their food are called heterotrophs.
Give reasons.
a. Decomposers are called cleaners of nature
ANS. Microorganisms such as bacteria and fungi are called decomposers.
Decomposers break down the dead parts of plants and bodies of dead animals, and release nutrients from them into the environment.
They are called the cleaners of nature.
They help in keeping the environment free of dead and rotting matter
b. Amoeba is classified as an unicellular organism.
ANS. Organisms such as bacteria, yeast, amoeba, etc. are made up of only one cell and are called unicellular organisms. They are so tiny that we can see them only with the help of a microscope.
Answer the following questions in detail.
a. State any three characteristics possessed by most living organisms.
ANS. Living Things are Made Up of Cells
Living Things show Movement
Living organisms need food to grow and to get the energy that they require to carry out various life processes.
b. Describe responsiveness to stimuli with suitable examples.
ANS. Any change in the organism’s environment that causes it to react is called a stimulus. The ability of an organism to react to a change in environment is called responsiveness.
EXAMPLES: 1.When you touch anything hot, you pull your hand away immediately. In this case, heat is the stimulus and the pulling away of the hand is the response.
2. Plants also show movement in response to stimuli such as light, temperature and touch.
ANS. Plants also show movement in response to stimuli such as light, temperature and touch. The roots of plants always grow downwards towards soil and water while the stem always grows upwards towards light. The stomata of the leaf open during the daytime and close at night. Lotus flowers open in the morning and close by sunset.
c. Excretion is also a characteristic of a plant. Explain.
ANS. Excretion also takes place in plants; however, like animals they do not have special organs of excretion.
Waste products in plants include carbon dioxide, oxygen, water vapour etc.
Oxygen is a waste product of photosynthesis while carbon dioxide and water vapour are waste products of respiration.
Plants also excrete substances as sticky secretions such as gum, resin, latex or crystals.
d. What do mean by tropism? Give suitable examples of tropism seen in plants.
HOTS ( Higher Order Thinking Skills)
a. On a hot summer afternoon, Mini notices that her favourite potted plant kept on the window sill looks dull and droopy. She picks up a mug of water and puts the water into the soil around the plant. By evening the plant looks like its old self. What do you think has brought about changes in Mini’s plant?
WRITE THE ANSWER BY YOURSELF FOR HOTS
ALSO WRITE THE MIND MAP?CONCEPT MAP
WORKBOOK EXERCISE
https://drive.google.com/file/d/1C6P4EH7GbkYFHJ5i6SMkW5f-rH3tMlFT/view?usp=sharing
