What is environment?
Everything outside our body is the environment.
What do we see in the environment?
We see living and non-living things in the environment.
What are the common non-living things that we see in the environment?
Soil, water and air are the common non-living things that we see in the environment. Other than these there are artifacts made by human beings such as chairs, tables, buildings, cars and other machines that make up our non-living environment.
How does soil contribute to the environment?
Soil is the most basic unit of the environment. It provides the substrate for plants and numerous other living organisms. It holds water. It provides the surface on which humans and other animals move. It observes and stores some of the harmful gases like nitrogen and carbon dioxide.
How does water contribute to the environment?
Water provides the wetness or humidity of the environment. It keeps the surroundings cool. It is important for sustaining life in the environment.
How is air important to the environment?
Air is composed of gases including the vital oxygen. All living organisms breathe by drawing air into their bodies. Air is important in regulating the local climate. Without air there can be no rainfall.
What is a tropical environment?
A tropical environment is one where the local weather conditions do not change drastically during a day or from season to season. Tropical environment is usually warm and humid as that in Chennai.
What are the common living things in the environment?
The common living things in the environment are microorganisms, plants and animals.
What are microorganisms?
Microorganisms are very minute living organisms. They are found in soil, water and air. Example: bacteria, amoeba.
What do microorganisms do in the environment?
Microorganisms have many roles in the environment. They fix gases in soil and water, they purify water, and they live inside the bodies of plants and animals. While most microorganisms are beneficial to humans some cause diseases to us, our animals and plants.
What plants do we commonly see in the environment?
We see grasses, herbs, shrubs and trees in the environment.
What animals do we commonly see in the environment?
We commonly see worms, insects, spiders, lizards, fishes, frogs, birds and mammals.
What is an insect?
Insect is an animal with six jointed legs. Many insects have wings while some do not have wings.
Where are insects found?
Insects are found practically everywhere. They are found inside our houses. They are also found in the remotest places on earth. Insects are the most abundant and common animals on earth.
Can insects be useful as human food?
Yes. Many kinds of insects including termites, ants, grasshoppers and beetles are eaten by humans in the different parts of the world. Termites are commonly eaten by people in Tamil Nadu.
What is a spider?
A spider is an animal with eight jointed legs. Spiders have the ability to spin webs. However not all spiders spin webs. All spiders are poisonous. But only a few species of spiders can cause harm to humans.
Do people eat spiders?
Yes. Some tribes in northeast India eat spiders.
What do frogs eat?
Most frogs eat insects. Some like the bullfrogs eat smaller frogs and other small animals. There are others like the green pond frog that eat aquatic plants.
Are all snakes poisonous?
No. Only some species of snakes are poisonous. In India there are more than 270 different species of snakes. Of these only around 50 species are poisonous.
Do all lizards have legs?
No. There are some lizards that look like snakes and do not have legs. In India legless lizards are found in Orissa.
Is the forked tongue found only in snakes?
No. Some lizards also have forked tongue.
Do all fish have scales?
Most fish have scales. However some fish like the eels and catfishes do not have scales.
Can fish survive on land?
Most fishes cannot survive on land. However there are some fish that have special sacs inside their body in which they are able to store air and survive outside water for short period of time. Example: eels (vilaangu), snakeheads (koravai).
Is the sting of a catfish poisonous?
Yes. Catfishes are equipped with poisons in specially adapted spines in their fins. The stings of catfishes can be very painful and the wounds thus caused can become infected.
Can fish climb palm trees?
There is a common fish called the Climbing Perch. This fish is capable of surviving without water through the dry seasons. Sometimes the fish seeks shelter between the fronds of palms that grow close to lakes and ponds during summer. The fish is locally called ‘panangottai’.
Why do dogs howl in the night?
Dogs howl and communicate with each other. This is a habit they have inherited from their ancestors the wolves. A dog howling in the night does not indicate anything bad or evil.
Does swarming dragonflies signal rain?
Some tiny insects are sensitive to changes in the atmosphere and are able to foresee rain. These tiny insects tend to emerge in large numbers. Dragonflies feed on insects and they normally swarm to catch these emerging tiny insects. Swarming dragonflies may therefore signal rain.
Why do termites swarm in the rainy season?
Termites that live in colonies breed and their colonies get over-populated. Whenever a colony is over-populated some members fly out to find new habitats for establishing fresh colonies. This is called dispersal. Dispersal normally happens during the rains as it may be easier for the termites to start new colonies in the wet soil.
What is the earthy odor that we feel after a rain?
The top soil is full of microorganisms. These minute organisms are active and due to their metabolism there are a number of gases released. These gases that are stored in the numerous pores in the top soil are released when the rain water enters the pores. This is why we get a typical odor after a rain.
Why is open defecation bad for the environment?
The human digestive system contains many parasites. These parasites come out along with the excrement and contaminate the soil and water. Contaminated soil and water causes the spread of intestinal parasites to other human beings. Sometimes, domestic animals feed on human excrement. They in turn pick up the parasites and pass them on to human beings.
What are common mosquito-borne diseases?
Mosquitoes commonly spread diseases like malaria, filariasis (elephantiasis), chickungunia and dengue.
What are common diseases spread by rats?
Rats spread plague and leptospirosis (rat fever).
What are common diseases spread by cats and dogs?
The most common and dangerous disease spread by cats and dogs is rabies. Rabies is a fatal viral disease and therefore it is good to have our pets properly vaccinated.
How to avoid snake bites?
Avoid walking in areas with tall grass and other plants. Do not walk without a light in the nights. Walking barefoot is unsafe. In places where snakes are common it is good to wear shoes while going out.
Why is it good to wash hands with soap before we eat?
There are lakhs and lakhs of microorganisms around us. Some of these microorganisms can be harmful to us. When we touch objects, our hands get easily infected with microorganisms. When we eat without properly washing our hands, these harmful microorganisms enter our bodies and cause diseases. Soaps have the ability to kill microorganisms. It is therefore good to use soap to disinfect our hands each time before we eat.