🌿 Living Organisms
Definition of Living Organisms:
Living organisms are those things that have life and show characteristics such as growth, movement, respiration, sensitivity, reproduction, excretion, and nutrition.
Growth and Development
Growth Definition :
Growth in living beings is not just an increase in size, height, and weight, but it also includes increase in different body parts.
Points:
- Happens in all living organisms.
- In animals, growth occurs only for a certain period.
- In plants, growth continues throughout life.
- Seen in organs like roots, stems, leaves.
Example:
- Increase in height of a child.
- Growth in length of plant roots and branches.
Development Definition :-
Development is the progress in an organism’s body, intelligence, work capacity, and skills.
Points:
- It is about learning and improvement, not just size.
- Includes physical + mental changes.
- Happens along with growth.
Example:
- A baby learning to crawl, walk, and speak.
- Improvement in thinking and skills.
Plants make their own food by photosynthesis
Animals depend on plants/other animals for food
Food → Energy → Growth (very important concept)
What Will Happen, if...
1. What will happen if there is a large beehive on a tree branch and some children light a fire under that tree?
Answer: The bees will get disturbed due to the smoke and heat. They will come out of the hive and may attack or sting the children to protect themselves.
Answer: The bees will get disturbed due to the smoke and heat. They will come out of the hive and may attack or sting the children to protect themselves.
2. What will happen if a hen and her chicks are picking grains and a cat or a snake approaches them?
Answer: The hen will sense danger and start making warning sounds. She will try to protect her chicks by hiding them under her wings or moving them away.
Answer: The hen will sense danger and start making warning sounds. She will try to protect her chicks by hiding them under her wings or moving them away.
3. What will happen if water is poured on one side of a mound of dry soil and a live earthworm is placed near the moist edge?
Answer: The earthworm will move towards the moist soil because it needs moisture for survival and prefers a damp environment.
Answer: The earthworm will move towards the moist soil because it needs moisture for survival and prefers a damp environment.
4. What will happen if many pigeons are gathered and there is a loud noise of firecrackers?
Answer: The pigeons will get frightened by the loud noise and immediately fly away to a safer place.
Answer: The pigeons will get frightened by the loud noise and immediately fly away to a safer place.
5. What will happen if a small baby in a cradle feels hungry or its clothes get wet?
Answer: The baby will start crying to express its discomfort or need, such as hunger or wet clothes.
Answer: The baby will start crying to express its discomfort or need, such as hunger or wet clothes.
6. What will happen if lotus buds are closed during the night and sunlight falls on them after sunrise?
Answer: The lotus buds will open in response to sunlight.
Answer: The lotus buds will open in response to sunlight.
7. What will happen when the sun sets and then it becomes dawn the next morning?
Answer: After sunset, birds return to their nests and sleep at night. At dawn, they wake up, start chirping, and fly out in search of food.
Answer: After sunset, birds return to their nests and sleep at night. At dawn, they wake up, start chirping, and fly out in search of food.
✅ Final Concept
All these answers show that living organisms respond to changes (stimuli) in their environment, which is an important characteristic of living things.
Response to Stimuli, Excretion & Reproduction
📘 1. Response to Stimuli
Definition:
The ability of a living being to sense its surroundings is called Stimulus.
The way it acts because of that sense is called Response (Reaction).
The ability of a living being to sense its surroundings is called Stimulus.
The way it acts because of that sense is called Response (Reaction).
Examples:
- Earthworms move away from sunlight and go into damp soil.
- Animals change their behavior when they sense danger.
- Plant roots grow towards water.
- Plant branches grow towards sunlight.
♻️ 2. Excretion
Definition:
Removal of waste materials from the body is called Excretion.
Removal of waste materials from the body is called Excretion.
Examples:
- Animals release carbon dioxide and water vapour while breathing out.
- Animals pass urine and release sweat.
- Plants store waste in leaves and bark.
- When leaves fall, waste is removed.
- Plants release gum or resin from stems.
- Roots also release some waste material.
🌱 3. Reproduction
Definition:
The process by which a living organism produces another organism like itself is called Reproduction.
The process by which a living organism produces another organism like itself is called Reproduction.
Examples:
- Some animals lay eggs → babies hatch from eggs.
- Some animals give birth to young ones.
- Some organisms grow from a small part of their body.
- Plants reproduce through seeds.
- Seed grows into a new plant (germination).
🎯 Very Short Revision:
- Stimulus → sensing surroundings
- Response → action
- Excretion → removal of waste
- Reproduction → producing young ones
