3rd Class

     Living Things Respond to Changes to their Surrounding   All living things respond to changes in their external environment. Organisms have sense organs like eyes, ear, nose, tongue and skin to detect these changes. Human respond to heat and cold in the surroundings by wearing cotton, light clothes and woolen clothes respectively. There is coordination between the brain and the sense organs to respond to changes in the surrounding. Sense organs receive the changes called the stimulus, which then reaches to brain through nerves. Brain interprets it and sends the message through the nerves to sense organs for respond. Removing hand on touching hot plate is an example of respond to the changes in the environment. Plants also respond to changes in their surroundings. Sunflower bends towards light. Light is stimulus and bending is response. Movement of root under the ground and stem more...

    Source of Food for Plant and Animal   Food is essential because it gives energy for growth and to do various activities of day to day life. Plants prepare its own food with the help of water, carbon dioxide and sunlight. Leaves of plant are green in colour because of the presence of chlorophyll. Plants prepare food for itself by trapping sun's light in the presence of water and carbon dioxide. Plants need little amount of food prepared by them for immediate consumption, remaining food is stored in other parts of plants like root, stem etc. Animals are dependent on plants for their food. Animals also eat the flesh of other animals. Hence animals are directly or indirectly dependent on plants. The process of food obtained by living things is best described by a chain called food chain.   Look at the following picture more...

    Food of Living Things         Different Animals have Different Feeding Habits On the basis of kinds of food eaten by the animals, they can be broadly classified into three groups.        Plant Eating Animals Animals like horse, cow, goat, buffaloes like to eat grasses whereas rabbits, rats and squirrels love to eat seeds, nuts and fruits. These animals are also called herbivores because they eat only plants or plant products.        Flesh Eating Animals Animals like lion, tiger, etc. eat the flesh of other animals. They are called carnivores.         Flesh and Plant Eating Animals Some animals eat plants and flesh both. Human beings, as well as few animals like crow, bear and some birds more...

   Breathing in Living Things   In breathing process, living organism, takes in oxygen and gives out carbon dioxide gas. There are special organs in the living body which perform these functions. These organs are called breathing organs. Different types of organisms have different kinds of breathing organs. The following table shows the organisms and their breathing organs.   Look at the following flow chart of breathing organs in different living organism:   Animals obtain oxygen through breathing process, which produces energy by oxidizing digested food. Like animals, plants also take in oxygen for breathing and give out carbon dioxide all the time.                                                      Which one of the following doesn't breathe?     more...

    Growth in Living Things   All living things, plants and animals, grow with time. Pattern of growth is different in different animals. Babies of all animals grow into adult with the passage of time. A seed grows into plant and plant grows into tree.   Look at the following flow chart of the growth in living things:      Look at the following pictures of growth in living things:                  Growth is one of the main characteristics features in living things. A non living thing does not have the characteristics as discussed above. For example, pen and pencil cannot grow because these are non living things.       more...

    Living and Non - Living Things   All the things can be classified into two groups. Living things Non living things   The things, which have life and can grow are called living things. The characteristics of non-living things are opposite to that of the living things. Non living things have no life or growth. Neither they need food nor there any activity inside their body. However, living things are further categorized into two types, as given below.             Types of Living Things    Living things have life and required food for their nutritional needs. The following characteristics are common to all kinds of living things.            Characteristics of Living Things   Look at the following flow more...

   Animal Kingdom   There are two types of living organism i.e. plants and animals that we have studied in the previous chapter. The characteristics feature of plants and animals are different. In this chapter we will study about the different types of animals.   Look at the following picture of different types of animals:                                      Dog                                           Cat                                      Lion                         Human            General Characteristics Features of Animals Animals move from one place to another in search of food more...

    Types of Animals on the Basis of Food Habits              Herbivores Look at the following picture of herbivores animals:                                       Cow                                        Buffalo                                 Camel   Animals like cow, buffalo, goat, camel feed on grasses, leaves, and grains, which are purely plant products. These animals are called plant eating animals or herbivores. These animals shows the phenomena of chewing the cud. In this process animals first fill the stomach with unchewed food. After some time they bring the food back into the mouth and then chew it properly. Herbivores have flat broad front teeth to cut the leaves and grasses. They chew the food with the more...