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Definition:

The skeletal system is the framework of bones in our body. It gives our body shape, support, and protection.

Main Parts of the Skeleton:

1. Skull – Protects the brain

2. Spine (Backbone) – Helps us stand straight and bend

3. Rib Cage – Protects the heart and lungs

Definition:

A human organ system is a group of organs that work together to do a special job in our body.

Main Points:

1. Our body has many organ systems.

2. Each organ system has a different function.

3. The digestive system digests food.

Main Human Organ Systems

1. Digestive system – Digests food and gives energy.

2. Respiratory system – Helps us breathe.

3. Circulatory system – Carries blood, oxygen, and nutrients.

4. Nervous system – Controls thinking and body actions.

5. Skeletal system – Gives shape and support to the body.

Definition:

An organ system is a group of organs that work together to perform a special function in our body.

Main Points

1. The human body has many organ systems.

2. Each organ system has a specific job.

3. Digestive system helps in digesting food.

Definition:

Digestive system Helps in digesting food and giving energy to the body.

2. Respiratory system Helps us breathe in oxygen and breathe out carbon dioxide.

3. Circulatory system Helps in carrying blood, oxygen, and nutrients to all parts of the body.

4. Nervous system Helps us think, feel, and control our body actions.

5. Skeletal system Gives shape and support to the body and protects organs.

Definition:

A human organ system is a group of organs that work together to do an important job in our body.

Main Human Organ Systems

1. Digestive System

   • Helps us digest food.

   • Gives energy to our body.

1. Root

• The root grows under the soil.

• It holds the plant firmly in the ground.

• It absorbs water and minerals from the soil.

2. Stem

• The stem is the main support of the plant.

Particle Theory of Matter

Particle theory says that everything is made up of tiny particles and these particles behave in certain ways.

Here are the 5 main ideas:

All matter is made of tiny particles.

Everything—air, water, solids, liquids, gases—is made of very small particles.

There are spaces between the particles.

1. Solid

• Has a fixed shape

• Has a fixed volume

• Particles are packed very tightly

• Example: Ice, rock, wood, pencil

2. Liquid

Vertebrates are animals with a backbone. They are divided into 5 main groups:

1. Fish

• Live in water

• Have gills to breathe

• Body covered with scales

• Lay many eggs

1. Thallophytes (Algae)

• Simplest plants — no true roots, stems, or leaves.

• They grow mostly in water (fresh or salty).

• They make their own food using sunlight water and Carbondioxid(photosynthesis).

• Some are green, others can be red or brown.

• Examples: Spirogyra, Seaweed, Ulva, Volvox

Investigating Variation 

Variation means differences among living things of the same species.For example, all humans are the same species, but we don’t all look the same — we have different heights, hair colors, and eye colors.

Investigation of Variation

To investigate variation, scientists or students can collect data and compare characteristics.

Example investigation: Investigating height in your class

1. Measure the height of all students in the class.

The Nervous System

The nervous system is one of the most important systems in our body. It helps us feel, move, think, and respond to what is happening around us. It acts like the contrl centerol for our whole body.

Main Parts:

1. Brain:

   • The main control center.

   • It helps us think, learn, remember, and make decisions.

1. Meaning:Variation means small difference in a species.

   
   

2. Example: All humans are the same species, but we are differ in skin type, hair colour, height etc.

   
   

3. Cause: Variation happens because of the genes.

   
   

4. Types:

   1. Inherited variantion

   2. Environmental Variation

      
      

What are species ?

ANS: Scientist group living organisms in to diffrent kinds , called species .

. A species is a group of organisms that all share the same characterastics .

key word

. classification

. It shows how every type of organism we know of is connected to all the others .

People use a lot of energy each day .

. our body use energy for moving , for thinking , for growing and keeping warm .

Energy - is the ability to do work .

Question

1. From were do we get energy ?

   ANS: Well, according to the law of conservation of energy.

We share our earth with million of other organisms .

What is conservation ?

ans: Saving something or someone

Key word

. Ecosystem - al around us is ecosystem.

. Urbanisation - The. process of an ingresing preperation .

Ozone is a gas . There is a layer of ozone high up in the atmosphere. The Ozone layer is about 25 kilometres above the ground.

Keywords:

Radiation - Known as UV - Full form of UV is Ultra Violet rays entering from the Sun.

. Too much UV rays can cause skin cancer.

. Can even harm the single cell organisms like plants and aquatic animals.

. Between the Earth and Sun, there is an invisible pale blue protective shield called Ozone layer.

Pollution happens when people throw waste or pollute the air.

Water Pollution

We throw water in water, so the fishes come and eat, so they die.

1. What is water pollution?

   Ans : Water pollution is dirty water.

Did you know?

Humans and food chain

Key words 

. Woolly mammoth

. Mammoth 

. Hunter 

. Gater

Food chain - Describes how different organisms eat other for survival . The food chain usually starts with a plant and ends with an animal . The food chain comprises of the producers , consumers and decomposers :

1. Plants - Producers 

2. Animals - consumers 

Primary consumers = herbivores or secondary consumers eat other animals .

Secondary consumers - carnivores

If carnivores eats another carnivore , it is called a tertiary consumer , Some animals play both roles like crows . They are called omnivores.

Adaptation - Helps animals to servive aand thrive in wild .

The process of adjusting according to the environment and situation is called adaptation .

Question

1. How do animals adapt ?

   ANS: There types of adaptation process in the animal world , That is : 1. Behairoral 2. Structural and physical

   Behaviural adaptation :

Animal cell are suruonded by a semi - permeatain membarain . cell membarain alows only spsific matirial to move in and out of the cell . The diffrent parts of the cell are called organells . The cytoplasm is a jelly like substence . Cytoplasm provides a surface for all the center of the cell . Mitochondria are the sites for cellular respiration in cell. It is the power house for the cells. ATP is needed for the functioning or growth and maintence of the body . The endoplasmic reticulam is a large network of membaraine bounds sheet . They help in transporting and exanchaging materials between the virouse regions of thecytoplasm . The cytoplasm reticulum is two types The smooth endoplasmic riticulume helps in the formantation of lips . The rough endoplasmic reticulum has ribosomes . When the damaged , the lysosome bursts .

What is a Cell?

A cell is the smallest unit of life . It’s like a tiny room where all the work happens to keep a living thing alive.Every plant, animal, and human is made up of cells! Types of Cells

There are two main types:

1. Plant cells 

2. Animal cells 

Both are similar, but plant cells have some extra parts!

Organism

Organ system - 11 organe system

Organ - 78 organs

Tissues

cells - 37 trillion - 12 zeros in trillion

11 organ system

Key words

1 . Trillion - A number with 12 0's .

2. Amoebae - A tiny living organism .

3. Obtained - Naturally obtained , Chemically obtained , Biologycally obtained , Mechically obtained .

4. Obtain - To get or to receive something .

5. Butcher - A person who cuts and sells meat .

Points and questions

1. Why does a plant need a cell?

   Ans: A plant needs cells because they are the fundamental building blocks for all functions providing structure, and enabling process like photosynthesis.

2. What is photosynthesis?

   Ans: The process plants use to convert light energy to chemical energy to produce their own food, sugar, and oxygen.

3. What is chemical energy?

2 . 5

Points

1. What is the meaning organisms ?

ANS : Organisms are living things that means they can breath , grow , move , eat , and reproduce .

2. What is micro ?

   ANS : The word 'micro' means very very small .

1. Mucles are organes that help us to move .

2. The mucles are atached to our bones.

3. Tendones are very strong.

4. And they don't stretch.

5. Mucles can get shorter .

6. This is called Contraction

Points

1. A joint is place where to bones meet.

2. There are two types of joints one is fixed joints second one is moveble joints.

3. The skull has fixed joints.

4. The crianium is made up of sevral bones .

5. This helps cranium to protect the brain.

The human skeletal system wasn't found by one person.

Yes , bones need blood.

There are 7 cervical vetibrae in almost all humans because They need to support the head

1. yes , animal organs work together

2. The name digestive system Came from the word digest

3. The meaning of respiration is to breath

Rain is water that falls from the clouds in the sky as drops.

Here’s a simple way to understand it:

1. Clouds form when water from rivers, lakes, or oceans evaporates into the air as water vapor.

2. The water vapor cools high up in the sky and turns back into tiny water droplets, making clouds.

3. When the droplets get too heavy, they fall to the ground as rain.

Rain is important because it gives water to plants, fills rivers and lakes, and helps animals and people.

1. Chlorophyll is a green pigment found in the leaf.

2. plants make oxygen from their leaves.

3. Plants give oxygen in the day because they need sunlight.

Asexual reproduction is a type of reproduction where only one parent is needed to make a new organism.

In this process, the new organism (offspring) is an exact copy of the parent — it has the same genes. Examples:

• Bacteria reproduce by splitting into two (called binary fission).

• Plants like money plants or potatoes can grow from cuttings or tubers.

• Hydra and yeast reproduce by budding.

. Epidermis:

• It is the outermost layer of the skin.

• Protects the body from germs, sunlight, and water loss.

• Makes new skin cells to replace old ones.

2. Dermis:

• The middle layer of the skin.

Cells are the smallest building blocks of all living things.

Just like bricks make a house, cells make up our body — and the bodies of plants, animals, and all living things.

There are two main types:

• Plant cells (found in plants)

• Animal cells (found in animals and humans)

Immune system

There was never just one first person to live on Earth. Humans didn’t suddenly appear — they slowly evolved over millions of years from earlier animals.

1. An ecosystem is a community where living things (plants, animals, humans, tiny organisms) interact with non-living things (air, water, soil, sunlight). 🌍✨

   For example:

   • A pond ecosystem has fish, frogs, plants, insects (living) and water, mud, sunlight (non-living).

   • All of them depend on each other to live.

1. Gives shape – It gives our body its shape.

2. Supports – It supports the body and holds us up.

3. Protects organs – Like the skull protects the brain, and the rib cage protects the heart and lungs.

4. Helps movement – Bones join with muscles to help us move.

5. Makes blood cells – Some bones make red and white blood cells.

7 Types of Nutrients & Examples

1. Carbohydrates → Give energyExamples: Rice, bread, potatoes, chapati

2. Proteins → Help in growth and repairExamples: Milk, eggs, pulses (dal), fish

3. Fats → Give extra energy and keep us warmExamples: Butter, ghee, nuts, oil

4. Vitamins → Protect us from diseasesExamples: Fruits (orange, mango), vegetables (carrot, spinach)

5. Minerals → Make bones and teeth strong, help body functionsExamples: Calcium (milk), Iron (spinach), Iodine (salt)

 Living Organisms

• They grow (baby → adult, seed → tree).

• They breathe (plants & animals).

• They eat food & drink water for energy.

• They move (run, swim, bend to light).

• They make more of their kind (reproduce).

 Non-living Things

• They do not grow.

• They do not breathe, eat, or drink.

• They can’t move on their own.

• They do not reproduce.

• They don’t react to things.