How do pine trees grow?

Did you know that pine cones contain seeds from which new pine trees can grow?
Each pine tree produces some male cones and some female cones.
Cone-bearing trees or shrubs are known as conifers. 
If you have pine trees growing near your home, try to find a cone of each type.
Ask an adult to cut the cones carefully in half from top to bottom, and then you can see what's inside each one.
Both male and female cones are made up of many scales arranged round a central axis.
In the female cone the scales are thick and woody.
Each scale carries two ovules, which will become seeds.
Male cones are smaller. They have pollen sacs on their scales, in which pollen grains are produced.
The wind carries the pollen grains, and some of them land between the scales of female cones.
It then takes three years for the male cells to join with female cells and produce a seed which will grow into a new pine tree.

How do plants make their food?

What color are the leaves of a lettuce? 
What color are the needles of a pine tree? 
What color are the leaves of grasses and most garden plants? 
The leaves of all these plants are green. 
Do you know why?
Unlike animals that have to eat green plants or other living things to stay alive, plants are able to make their own food.
All living things are made up of cells, but plant cells are different from animal cells.
The cells in the leaves of most plants contain tiny green parts called chloroplasts. 
Each chloroplast contains the chemical called chlorophyll that makes the leaves green.
The chloroplasts use sunlight, carbon dioxide and water to make food for the plant.

The process by which a plant makes its own food using sunlight, water, and carbon dioxide is called photosynthesis. 

Sunlight shines into a leaf through its outer cells, which are clear like glass.
The water comes from the soil, through the roots and the stem, and into the leaf.
The air gets into the leaf through tiny holes called stomata.
Inside the leaf, the chloroplasts use the sunlight as energy.
This energy helps to make sugars by combining water with the carbon dioxide that's found in the air.
The sugars are then turned into a substance called starch.
Grains of starch are stored in the cells of the leaf until the plant needs them for food.
During the process called photosynthesis, the chloroplasts inside the leaves of a plant use sunlight, carbon dioxide, and water to make food.

What do plants need to grow?

What do plants need to grow?

Do you have any plants growing in flowerpots around your home?
Do you look after them?
How do you do this?
You probably keep the plants in a place where sunlight can reach their leaves.
And you probably water the soil regularly.
You might even occasionally add plant food to make sure your plants grow strong and healthy.

What do plants really need? 

Plants need sunlight and water. 
Plants also need minerals and nutrients to make them healthy. 
The soil in which the plants grow usually contains these minerals and nutrients.
Both indoor and outdoor plants need sunlight, water, air, minerals, and nutrients to grow strong and healthy.
Plants also need two gases from the air—oxygen and carbon dioxide.
Plants breathe oxygen in and out.
They use carbon dioxide from the atmosphere to help them make their food.
There is also air in the soil, which plants don't take in but which they do need for healthy growth.

Fossils for kids - What are Fossils?

Rocks often contain the remains of living things that died long ago. These remains are called fossils. 
The kinds of rock that contain most fossils are called sedimentary rocks.
Sedimentary rocks build up in layers very slowly.
So we know that the rocks near the surface, just under the soil, are younger than the layers of rock below them. The oldest rocks are right at the bottom.
By studying chemicals in the rocks, scientists can tell how old they are.
 
This fossil of a reptile was found in Switzerland. The animal probably lived about 200 million years ago.

Rocks that were made less than 300 million years ago contain fossils of all kinds of different animals and plants, including horses, tigers, birds, dinosaurs, dragonflies, and flowers.
In rocks that are between 500 million and 300 million years old, fewer animals and plants have been found, though there are plenty of fossils of fish, plants without flowers, and simple animals such as mollusks.
Older rocks, made over 500 million years ago, contain no vertebrate fossils. 
The oldest animal invertebrate fossils are about 700 million years old. These animals include very simple creatures like jellyfish and worms.
The oldest fossils are about 3.5 billion years old and these fossils are of very primitive bacteria.
Scientists believe that fossil records show that life began with very small, simple creatures.
As time went by, more and more complex creatures appeared.
The most complex animals and     plants-mammals, bird, and flowering plants-appeared last of all.

Animal evolution and evolution of all living things on earth

Some scientists believe that living things developed from other simpler living things, which have slowly become more complex over millions of years.
There are enough fossils to show clearly how some kinds of animals have changed over time.
Studying fossils has helped scientists to reach the conclusion that mammals have branched off and followed reptiles.
Other fossils show what the ancestors of some animals, such as the camel, looked like.
Camels branched off a line of small animals the size of a fox. Camels then developed as larger animals with hooves, a long neck, and large teeth.

The animals that became better suited to their surroundings are the ones who have survived.
The giraffe's long neck, for example, enables it to reach high up into trees and eat the leaves there.
Scientists believe that animals have survived because their ancestors were the ones that could make best use of their surroundings.
Some animals, such as the dinosaurs, were not able to survive. 
No one knows exactly why they died out. Other species have also disappeared completely.
Some were hunted until they became extinct.
Others were destroyed by disease or by changes in climate.

 Over millions of years, bigger and heavier elephants appeared.
The mammoth was about 15 feet (4.5 meters) tall.
There are now only two kinds of elephant— the African and the Indian elephant. The African elephant is about 11.5 feet (3.5 meters) tall.

Classification of Plants

Do you like climbing trees? Or looking at flowers? Or eating fruit? If so, you like plants! Scientists who study plants are called botanists. Botanists have discovered and named 350,000 different kinds of plants— and they find new ones every year! They classify their discoveries, that is, sort them into groups. Some living things are hard to sort, so botanists disagree on their classifications. Algae may be placed in the kingdom of plants or in the kingdoms of protists or monera. Fungi may be called a separate kingdom or may be called plants. Plant groups that most botanists agree on are mosses and liverworts; ferns, club mosses, and horsetails; and seed-bearing plants.

Algae and fungi
 

Mosses and liverworts

 
Ferns, club mosses and horsetails


Seed-bearing plants

Reproduction - What is Asexual and Sexual reproduction?

What is Reproduction?

Human beings have babies. 
Fish lay eggs which hatch into young fish. 
Trees grow seeds which can grow into new trees. 
Living things make copies of themselves. 
This is the process of reproduction.

Asexual reproduction

There are two different kinds of reproduction.
In one kind, there is only one adult of the species, and the young ones look exactly the same as their parent. This kind of reproduction is called asexual reproduction.
Living things reproduce like this in several different ways.
The simplest living creatures reproduce by just splitting in two.
Most creatures that are made up of only one cell reproduce in this way.
Even some simple animals such as sea anemones, whose bodies are made up of many cells, can do this.
 Asexual reproduction
Many plants can make new plants from a small piece that has broken off, such as a twig or stem.
This is useful if the plant has been damaged by animals or by strong winds.
It is also useful to gardeners, because it means that they can take cuttings, which grow into new plants.
The plants grown from cuttings will be exactly the same as the parent plant.
Asexual reproduction

Sexual reproduction

In sexual reproduction, there are two adults of the species— one male and one female. 
The young ones are not quite the same as the parents.
Human beings reproduce in this way.
You don't look exactly like your parents, though you may look a bit like both of them.
This is true of other animals and plants with two parents. They take some of their features from one parent and some from the other.
Sexual reproduction
For sexual reproduction to take place, one cell from the male must unite with one cell from the female.
In animals, the male produces cells called sperm and the female produces egg cells.
When one egg cell joins with one sperm cell, fertilization is accomplished.
The fertilized egg then begins to develop into a new organism.
Fertilization can happen inside or outside the female's body.
In most fish and frogs, the female lays eggs and the male releases his sperm over them.
In birds and mammals, the male's sperm fertilizes the eggs inside the female's body.
In plants, the male cells are called pollen.
Pollen is carried from male flower parts to female flower parts by insects or by wind.
The pollen fertilizes the egg cells and produces seeds, which grow into new plants.
In many plants, the male and female flower parts are in the same plant.
Voluntary Movement - Definition - What is Voluntary Movement?

Voluntary Movement - Definition - What is Voluntary Movement?

Voluntary Movement - Definition - What is Voluntary Movement?

When you turn the pages of a book, you are moving your hands and fingers.
As you read, your eyes are moving as they follow the words on the page.
These body movements are happening because you are making them happen.
You could easily stop them if you wanted to.
This kind of body movement is called a voluntary movement. 
Voluntary movements of the body are all the movements that you make your body do, such as walking, running or picking up a pencil.

What does the nervous system do?

What does the nervous system do?

Our brain sends them messages through a network of nerve cells that make up the nervous system.
When you decide to pick up a pencil, your brain sends a message through the nervous system to the muscles in your arm and hand to start moving.
The nervous system also carries messages to the parts of your body that move without your control, such as your heart and stomach.
Most animals have some kind of nervous system. But no animal has a brain as well developed as the one in human beings. 
When animals are in danger, messages travel through the nerve cells to tell the different parts of their body what to do.
If a mouse sees a cat, messages will be sent quickly through the nerve cells of the mouse to tell it to run away.
In the same way, a snail will pull its head into its shell for protection when it senses a threat.
What does the nervous system do?

Ocean Food Chain

There are plants in the seas and oceans as well as on land. Tiny plants and animals are part of a layer of millions of living things near the surface of the oceans. All these things are called plankton. The plankton that are plants use light from the sun to help make their own food. The plankton that are animals eat the plants or each other.
Fish, shellfish, and seabirds feed on the plankton. Then these creatures are eaten by larger animals, such as seals and some types of whales. This makes a food chain in the sea. So the food chains of the sea begin with plankton.

Herbivores and Carnivores

Herbivores and Carnivores

The grasslands of Africa are covered in grasses and other plants.
Between periodic droughts, there is usually plenty of sunlight, carbon dioxide, and water for these plants to grow and make their own food.
Herds of antelopes feed on the plants.
But a herbivore such as an antelope stores only about 10-20 per cent of the energy from its food.
About 80-90 per cent of the energy is used by the antelope to carry out life functions.
Small groups of lions prey on the antelopes.
When a carnivore such as a lion eats a herbivore such as an antelope, the carnivore gets only the 10-20 per cent of energy stored in the body of the herbivore.
The farther along the food chain you go, the less stored energy there is available.
This means there must be many more antelopes than lions.
Similarly, there must be many, many plants to support the antelope population.

Omnivore definition

Omnivore definition

All living things need some kind of food to stay alive.
Food gives them energy and helps them to grow and to stay healthy.
Green plants can make their own food.
Some animals eat plants, and some animals eat other animals.
Food energy passes from plants to animals in a long chain.
This is called a food chain.
Human beings and some other animals, such as bears and pigs, are called omnivores. 
They eat both plants and animals.

Carnivorous animals

Carnivorous animals

All living things need some kind of food to stay alive.

Food gives them energy and helps them to grow and to stay healthy.

Green plants can make their own food.

Some animals eat plants, and some animals eat other animals.

Food energy passes from plants to animals in a long chain.

This is called a food chain.

Meat-eaters are called carnivores. 

Herbivores Animals

Herbivores Animals

All living things need some kind of food to stay alive.
Food gives them energy and helps them to grow and to stay healthy.
Green plants can make their own food. Some animals eat plants, and some animals eat other animals. Food energy passes from plants to animals in a long chain.
This is called a food chain.

The animals that eat plants, such as sheep or rabbits, are called herbivores. 
Herbivores are eaten in turn by animals that eat meat, such as foxes, which eat rabbits.
Meat-eaters are called carnivores.


List of some Herbivores Animals


  • Bison
  • Bovinae
  • Buffalo
  • Cattle
  • Tamaraw
  • Saola
  • Wisent
  • Yak
  • Kouprey
  • Gazelles
  • Goats
  • Sheep
  • Deers
  • Giraffes
  • Caribou
  • Elk
  • Moose
  • Chevrotain
  • Koalas
  • Kangaroos
  • Horses
  • Zebras
  • Donkeys
  • Rabbits
  • Hares
  • Pikas
  • Rhinoceroses
  • Elephants
  • Hippopotamus
  • Llama
  • Camels
  • Rodents
  • Capybara
  • Chinchilla
  • Beaver
  • Mice
  • Octodontids
  • Guinea pig

  • Reptiles
  • Squamata
  • Uromastyx
  • Solomon Islands skink
  • Iguanas (mostly herbivorous)

  • Tortoises (most land-based species)

  • Birds - Some birds are herbivorous, and some are not.

  • Insects
  • Butterflies
  • Katydids
  • Treehoppers
  • Leafhoppers
  • Ants
  • Moths
  • Grasshoppers
  • Caterpillars

  • Garden snails and slugs

What is a Food Chain?

What did you have to eat today?

Did you have vegetables, fruit, cereal, fish, or meat?

All living things need some kind of food to stay alive. 

Food gives them energy and helps them to grow and to stay healthy.
Green plants can make their own food.
Some animals eat plants, and some animals eat other animals.
Food energy passes from plants to animals in a long chain.
This is called a food chain.

Food Chain - Lichen - Great greyslug Common toad Grass snake
Food Chain - Lichen - Great grey slug - Common toad - Grass snake

Food chain - Thistle - Garden snail - Song thrush Sparrowhawk
Food chain - Thistle - Garden snail - Song thrush - Sparrowhawk

Food Chain - Blackberries - Bank vole - Stoat
 Food Chain - Blackberries - Bank vole - Stoat

All food chains begin with plants.
Green plants take in water and a gas called carbon dioxide.
Light from the sun helps the plants join these together to make sugars.
These sugars are the plants'food.

Herbivores Animals

Next in the food chain come the animals that eat plants, such as sheep or rabbits. These animals are called herbivores. Herbivores are eaten in turn by animals that eat meat, such as foxes, which eat rabbits. Meat-eaters are called carnivores. Human beings and some other animals, such as bears and pigs, are called omnivores. They eat both plants and animals.
Rabbit - Herbivores Animals
 All food chains begin with plants. Green plants take in water and a gas called carbon dioxide.
Light from the sun helps the plants join these together to make sugars.
These sugars are the plants'food.
Next in the food chain come the animals that eat plants, such as sheep or rabbits.
These animals are called herbivores.
Herbivores are eaten in turn by animals that eat meat, such as foxes, which eat rabbits.

Carnivorous animals

Meat-eaters are called carnivores.
Lion - Carnivorous animals

Omnivores animals

Human beings and some other animals, such as bears and pigs, are called omnivores.
They eat both plants and animals.
Bears - Omnivores animals

Diseases Caused by Bacteria

Some kinds of bacteria live on you! 
There are millions of bacteria on your skin and inside your mouth, nose, and lungs.
A great many live in your intestines.
Other kinds of bacteria live in the air, in water, or in the top layers of soil.
Bacteria, whether harmful or beneficial, can be spherical, rod-shaped, or spiral.
Each of these harmful bacteria causes a serious illness or disease.

Spherical bacteria
pneumonia



Boils blood poisoning



Sore throat
Scarlet fever



Rod-shaped bacteria
Tuberculosis


Tetanus



Typhoid fever



Spiral bacterium

Cholera

What is Osmosis?

When we feel thirsty we have a drink.
We take water into our bodies by swallowing it.
Plants don't swallow.
So how do they take in water?
On a plant's roots, there are tiny growths called root hairs. Plants take in water and nutrients through their root hairs, using a process called osmosis.
Osmosis is the movement of liquid from one solution into another through a membrane that separates them. A solution is a mixture of a liquid and some dissolved substances. A membrane is a thin "skin" that allows some substances, but not others, to pass through.
During osmosis, water containing nutrients moves from the soil, through membranes covering the root hairs, and into the roots. The membranes allow the water to seep into the root hairs, and also prevent nutrient-rich liquid from leaving the roots.

This close-up photo shows the tiny root hairs very clearly. Water moves through the membrane covering the root hairs, by osmosis, and into the root.

Water enters the plant through its root hairs.
In plants the food is made into the leaves, from where it travels to other parts, such as the stems and roots. Plants have a juice inside them called sap. The sap is like the blood of the plant. In many plants, it flows through special tubes, called phloem, which carry the sugars to all the plant's cells.

If you cut off the stem of some plants, such as the sugar cane, you will see a drop of sap forming at the cut end. This sap contains sugars which feed the plant, and we can use it to make sugar. Some plants contain other liquids, which we can use. We can make rubber out of the milky liquid that oozes out of rubber trees.


When does osmosis work?
You can find out in this experiment, using any root vegetable, such as a potato or a yam.

Plants in the desert – how they grow?

Most plants store water in their roots, stems and leaves.
Each time it rains, they refill their store.
But in the desert it might not rain for many months, or even years.
Then it falls as a short, heavy shower.
When it rains, the shallow, wide-spreading roots of a cactus can soak up the water very quickly, before it evaporates.
The leaves of the cactus become swollen with the extra water. They will act as a water store, supplying the plant with the water it needs. Other desert shrubs send down deep roots to reach groundwater far below the surface.
There are even plants, like the welwitschia of the Namib Desert, that trap the tiny droplets of water which form when the desert fog condenses. The water collects in their twisted leaves and trickles down to the roots.

Watch roots grow
Fill a jar almost full of water. Fix an onion in the neck of the jar. Make sure its base is in the water.
Watch the onion roots grow.

Growing Seeds - Water for growth

When you look at some flower seeds, it's often hard to imagine that they can grow into the lovely flowers in the picture on the packet. Seeds look as if they have no life in them at all.
However, seeds have all the food they need to start growing. So why don't they grow inside their packet? Seeds need three other things to begin growing. They need oxygen, warmth and water. If they have these three things, the seeds start growing. They use the nutrients stored inside them, the water they absorb from the soil, and the oxygen they take from the air. Some seeds stay dormant up to 50 years before they start growing, and then only if the conditions for growth are right.
There is only a small amount of nutrients inside each seed. When this is all used up, plants must make their own food.

Plants get their food from the soil. They soak up water from the soil, through their roots. This water has nutrients dissolved in it. Not all soil contains the nutrients that plants need. Sometimes a farmer or gardener has to add these nutrients to the soil in the form of fertilizers. These are washed into the soil by the rain, and the fertilizers are picked up by the plant's roots in the same way as if they were natural nutrients.
Farmers spread fertilizer on their land to put more nutrients into the soil. Then they can grow healthier crops.

Water Evaporation and Condensation

Water is constantly on the move, whether in the oceans and rivers, in a pond that looks completely still, or in a glass of water. Water molecules move about at different speeds all the time. If they move fast enough, some break away from the surface and enter the air. This is called evaporation. Some of the molecules then fall back into the water. But others become water vapor and are carried away by air currents. In this way some of the water is gradually lost to the atmosphere.
You can see this happen if you leave a saucer of water uncovered indoors. After a time, there will be no water left. It will all have evaporated.
Wet laundry on a clothesline dries more quickly in a breeze. The wind carries away the water molecules soon after they enter the air from the washing. Hardly any of them fall back on the clothes.

When water is heated, all of its molecules speed up and more of them escape. If water is made hot enough, all the molecules eventually escape and the water boils away. All of it becomes water vapor.
Heat speeds up evaporation. Cold slows it down and may even stop it, turning the water vapor back into water droplets. This process is called condensation. When you take a hot bath, molecules from the bathwater escape into the air and become water vapor. Some of them touch the cold bathroom walls and windows, and this cools them down and turns them back into drops of water. The walls, windows and the bathroom mirror become misty.
The insides of windows sometimes become misty on rainy days for the same reason. Inside a warm room, molecules of water vapor are moving about. Some of them meet the glass of the windows, which the rain has cooled. The loss of heat turns the water vapor near the glass back into water. If it gets cold enough at night, the water on the window will freeze and you may wake up to find your windows are frosty on the inside.
These wet clothes will dry faster when the wind is blowing. The water molecules evaporate into the air, and are blown away by the wind.
 
When water is cold, very few molecules will evaporate.
When water is warmed, the water molecules will escape more quickly from the surface into the air.