Lifespan of Animals & Organisms

The period from birth to the natural death of an organism represents its lifespan. Every organism has a specific average lifespan. It means every organism grows and lives for a particular length of time. Lifespan may range from one day to 4000 years. The living organisms do not survive indefinitely on this earth. Every individual … Read more

Human Circulatory System

The organ system of human beings (and other animals) which is responsible for the transport of materials inside the body is called circulatory system. The various organs of the circulatory system in humans are: Heart, Arteries, Veins and Capillaries. Blood is also considered a part of the circulatory system. So, the human circulatory system consists … Read more

Transport in Plants

The body of every organism (plant or animal) is made up of cells. A large organism-has millions and .millions of cells in its body. In order that the organism may be able to maintain its life and survive, all its cells must be supplied with essential substances like food, oxygen, water, etc. So, some arrangement … Read more

Respiratory System in Humans

In human beings, many organs take part in the process of respiration. We call them organs of respiratory system. The main organs of human respiratory system are: Nose, Nasal passage (or Nasal cavity), Trachea, Bronchi, Lungs and Diaphragm. The human respiratory system begins from the nose. Our nose has two holes in it which are … Read more

Respiration in Plants

Like animals, plants also need energy. The plants get this energy by the process of respiration. Plants also use oxygen of air for respiration and release carbon dioxide. Thus, the respiration in plants also involves the exchange of oxygen and carbon dioxide. So, oxygen and carbon dioxide are called respiratory gases. The respiration in plants … Read more


We have just studied that digested food is assimilated into the body of the living organisms. The assimilated food is used mainly for two purposes : 1. Assimilated food is used as a fuel to get energy for various life processes, and 2. Assimilated food is used as a material for the growth and repair … Read more

Types of Respiration

Respiration can, however, also take place in the absence of oxygen (of air), though it is very rare. This means that oxidation of food to obtain energy can occur in the presence of oxygen as well as in the absence of oxygen. Based on this, we have two types of respiration : aerobic respiration and … Read more

Nutrition in Amoeba

Amoeba is a unicellular animal. Amoeba eats tiny (microscopic) plants and animals as food which float in water in which it lives. The mode of nutrition in Amoeba is holozoic. The process of obtaining food by Amoeba is called phagocytosis (‘Phagocytosis’ means ‘cell feeding’). The various steps involved in the nutrition of Amoeba are : … Read more

Nutrition in Animals

We have just studied the nutrition in plants. We have learnt that plants are autotrophic organisms which can manufacture their own food. So, plants don’t have to look to others for getting their food. They are food producers themselves. But this is not so in the case of animals. Animals are heterotrophs and hence they … Read more

Nutrition in Plants

Just like other organisms, plants also require food which can supply energy for their various metabolic activities. Though animals can move from one place to another in search of food, plants just stand still at one place and make their own food. Green plants are autotrophic and synthesize their own food by the process of … Read more