Plants reproduce their own kind to continue their existence. Plants can reproduce from Seeds, spores or other plant parts. Most flowering plants reproduce from seeds.
Dispersal is the phenomenon of carrying the fruits or seeds to distant areas in order to spread them.
Fruits and seeds are dispersed so that young plants can get sufficient space, light, water and nutrients to grow well.
The surroundings in which an animal lives is called its habitat
Animals undergo changes in their living habitats and body structures as the environment changes. Adaptations are changes that are slow and gradual and take place over a period of time.
The table given below shows the body coverings in different animals.
Animals
Body coverings
Functions
1. Snail, turtle and tortoise
Shell
Protects the body from injury and from the attack of enemies
2. Fish and reptiles
Scales
Protect the body
3. Birds
Feathers
Help them in flying and in keeping their body warm
4. Mammals
Hair and fur
Protect their body and keep them warm
Tit bits
TUATARA
There is no other reptile like the tuatara. While other reptiles are basking in the sun to get warm, the tuatara sleeps and comes out only at night, to feed on spiders and beetles. It is active at temperatures as low as , twenty degrees cooler than any other reptile. As it is so cool the tuatara moves and functions very slowly.
It breathes only once every seven seconds when. It is moving, and once an hour when it is resting.
The table shows different feeding habits.
Feeding habit
Animals
Adaptations
Herbivores
Cow, sheep, goat, rabbit
Sharp front teeth and large flat back teeth
Carnivores
Lion, wolf, frog, lizard, snake, owl, eagle
Sharp pointed front teeth, strong back teeth, sharp strong claws and hooked beak
Omnivores
Humans, bear, rat
Well - developed teeth.
Sucking
Butterfly, leech, honeybee, sun-bird
Proboscis in butterfly, honey bees, suckers in leech, long beak in sun-bird
Insectivores
Chameleon, frog, lizard,
Long tongue in lizard chameleon
The table shows different organs aiding in breathing.
Human body (Nervous system bones and muscles)
Tit bits
The longest and strongest bone in the body is the thigh bone (femur).Its length is about a quarter of your height. It can take a load along the bone of over a tonne, but sideways blow can break it much more easily.
The bones and joints in our body form the skeletal system while various muscles form the
Muscular system. Together these systems help us to move and perform various movements,
The skeleton gives shape and support to our body. It consists of the skull, backbone, ribcage, bones of arms and legs, and the girdles.
The backbone is not a single bone. It is about a quarter of your height. It can made up of 33 small bones called Backbone is also called the vertebral column. It protects the spinal cord.
The rib cage is made up of 12 pairs of long, thin curved bones called ribs which protect the lungs and the heart. Our skull protects the brain and supports the head. The shoulders are supported by girdles. There are long bones in the arms and the legs. The whole skeletal system is composed of 206 bones.
Bones are light but very strong. To remain strong and healthy, bones require vitamin D, calcium and
The place where two bones meet is called a joint. Joints can be movable or Except the lower jaw, all the other bones of the skull are immovable. Movable joints work in different ways to enable a wide variety of movements.
The hinge joint works like the hinge of a door. The knee joint and the joint of the forearm are examples of hinge joints.
The ball and socket joint in our shoulders enables us to rotate our arm in a full circle. The ball like head of the upper arm bone fits into the cup-like socket of the shoulder bone.
The pivot joint in the neck helps you move your head from side to side. The sliding Joint in the wrist helps the bones to slide over each other.
Muscles, by contracting and relaxing, help the bones to move. Most of the muscles Work in pairs. When one set of muscles contract, the antagonistic muscles expand and vice – versa.
The movements which are in our control are called voluntary movements. The muscles which help in voluntary movements are called voluntary muscles. The facial muscles, the muscles of the arms and the legs, the muscles in our hands and feet are some voluntary muscles.
The movements which are not under our control are called involuntary movements. The muscles which enable involuntary movements are called involuntary muscles. The muscles of the heart, lungs, intestines, and more...
Soil, Rocks and Minerals
Synopsis
Tit bits
The Tajmahal, considered one of the wonders of the modern world, is made entirely out of marble. It also has gemstones embedded as decorations. Gemstones are precious rocks.
The land on the earth is made up of soil and
Rocks are made up of minerals.
There are three kinds of rocks - igneous, sedimentary and metamorphic.
Igneous rocks are also known as fiery Igneous rocks such as granite and basalt are formed when magma cools above the surface of the earth,
Granite rock is made of mica, quartz and
Sedimentary rocks are formed from older rocks that have been broken into tiny fragments.
g., Shale, sandstone, conglomerate and limestone. Sand stone is made of quartz.
Limestone is made of
Metamorphic rocks are formed when igneous or sedimentary rocks undergo changes due to heat and pressure.
e.g., Marble, slate, quartzite and gneiss.
Rocks are used as building materials, for extracting metals and as gemstones in jewelry.
Coal is a sedimentary rock formed from the remains of plants.
Petroleum is formed from the remains of plants and animals in the sea.
Soil is formed by the breaking down of rocks into smaller pieces.
The process of wind or flowing water washing away the top part of soil is known as soil erosion.
Deforestation, farming and over-grazing increases soil erosion.
The protection of soil from erosion is known as soil conservation.
Soil can be conserved through terrace or step-farming, afforestation, by providing soil cover, growing shelter belts and by building embankments.
Air, water and weather
Tit Bits
Synopsis
Ants can feel a storm coming. They collect food when they feel a storm is on the way.
Changes in air is on the way. Changes in air pressure warn them.
The blanket of air that surrounds the earth is called the It protects life on earth in various ways.
The atmosphere has troposphere and stratosphere layers.
The layer nearest to the earth is the tropo- sphere.
The layer that lies above the troposphere is the
Air is a mixture containing 78% of nitrogen, 21% of oxygen and 1% of other gases including carbon dioxide. It also has dust, smoke and water vapor.
Air has weight, it occupies space. Air exerts pressure in all directions, Substances that make water unfit for consumption are called impurities,
Water is very important to all living things. Harmful impurities in water have to be removed to make it fit for drinking.
Sedimentation, decantation and filtration are used for removing insoluble impurities in water.
Distillation is used to remove soluble impurities in water.
Sedimentation and filtration are used for removing insoluble impurities. Chlorine is added to kill germs and help make the water safe for drinking.
The Moon
Tit bits
The moon’s surface is very, old.
The youngest rocks brought back by the Apollo astronauts are more than three thousand million years old.
ARYABHATTA was the first to tell us that eclipses occur because of the shadows cast by the earth and the moon
The branch of science that deals with the study of celestial bodies is called
The moon is the natural satellite of the earth.
The moon does not have any light of its However, we are able to see the moon because it reflects the sunlight.
The surface of the moon is covered with craters, mountains and valleys.
The moon circles the earth, which causes the shape of the lit portion to change. We see different parts of the moon while it orbits around the earth. These changing shapes are called phases of the moon.
There are five major phases of the moon.
·- New moon - Crescent
- Half moon
- Gibbous
- Full moon The moon pulls objects towards itself with less force (gravity) than the earth does. So we would find it very difficult to walk on moon. Unless we are weighed down, we would float.
Stages of waxing phase
New moon thin crescents Half-moon Gibbous moon Full moon
Stages of waning phase
Full moon Gibbous moon Half-moon Thin crescents New moon
As the moon has no air or wind, the astronaut’s footprints will remain there forever.
Force, work and energy
Tit bits
Friction produces heat which is not always a disadvantage. For e.g., we use the heat produced by friction to light a match stick
A force is a push or a pull. It can help us do work.
A simple machine is a tool that helps us to do work easily. It does work when we apply a force.
There are different classes of simple machines:
(a) Lever. (b) Pulley.
(c) Wheel and axle. (d) Inclined plane.
(e) Screw. (e) Wedge,
A lever is a simple machine. It is a rigid rod that turns about a fixed point called fulcrum. It consists of fulcrum (F), load (W) and effort (P)
Levers are classified into three kinds according to the position of fulcrum, load and effort.
The three types of levers are shown in the table below:
Safety and first Aid
Tit bits
Fixed – time traffic lights were invented in the United States and introduced in New York 1918.the purpose of the traffic light is to control the flow of traffic, determine the right way at intersections and give greater safety to drives.
Synopsis
First Aid is the first medical help given to an injured person before a doctor arrives. The most important thing while giving first aid is to stay calm.
Safety on the road is more important than ever before because of the rapid increase in the number of vehicles. Read and follow road signs. They are meant for your safety. Always follow safety rules on the road and at home.
For cuts and scratches Germs can enter a body through uncovered cuts or wounds and cause infection.
Wash away all dirt around the wound.
Clean the affected area with cotton wool soaked in an antiseptic lotion.
Place a thick pad of cotton wool or sterilize gauze on the wound and press it with your thumb and fingers. This will stop bleeding in most cases.
A tourniquet can be used. This is a bandage tightly tied over the wound to stop bleeding.`
Wrap a sterile gauze bandage around the wounded area.
When the skin is cut by a dirty or rusted object, germs may enter and cause a dangerous disease called tetanus. Consult a doctor for an anti-tetanus injection.
For nose bleeds keep the patient upright in a comfortable position with his head held back.
Press the bleeding side of the nose firmly.
Keep an ice-pack or wet cloth on the nose and the head of the patient.
Ask the patient to breathe through his mouth and not to blow his nose.
A little bit of bleeding from the nose is harmless but if the bleeding is heavy, send for the doctor.
For sprains the tissues around a joint get torn we call it a sprain. Sprains cause swelling and sometimes discoloration of the skin. They are very painful.
Keep on applying ice-packs or ice-cubes on the injured joint till the swelling subsides.
For fractures A crack or a break in a bone is called a fracture Keep the patient calm and comfortable and send for the doctor.
TUATARA
There is no other reptile like the tuatara. While other reptiles are basking in the sun to get warm, the tuatara sleeps and comes out only at night, to feed on spiders and beetles. It is active at temperatures as low as , twenty degrees cooler than any other reptile. As it is so cool the tuatara moves and functions very slowly.
It breathes only once every seven seconds when. It is moving, and once an hour when it is resting.
Friction produces heat which is not always a disadvantage. For e.g., we use the heat produced by friction to light a match stick
Apply a splint to give support to
