Excretion The biological process of removal of excess or toxic wastes from the body is called excretion. Many unicellular organisms remove these wastes by simple diffusion from the body surface into the surrounding water. Osmoregulation: The process of …

Nervous System in Animals Imagine that bright Light is focussed on our eyes or we touch a hot object We are able to detect the change and respond to it with movement in order to protect ourselves. All this movement, in response to the environment, is ca…

Coordination in Plants Plants show two types of movement one dependent on growth and the other independent of growth. Some common observations are: The leaves of the touch-me-not plant begin to fold up and droop on being touched. There is no growth inv…

Hormones in Animals Hormones are chemical substances secreted in trace amounts by specialized tissues called endocrine glands. Characteristics of Hormones They are specific chemical messengers. They are secreted by endocrine glands. They are poured dir…

Types of Reproduction Living beings mainly reproduce by two methods – asexual reproduction and sexual reproduction. The modes by which different organisms reproduce depends on the body design of the organisms.

Asexual Reproduction Characteristics Certain body cells of an organism undergo re-peated mitotic divisions and form two or more new individuals of the same kind. The new individuals produced are genetically identical to their parents. Advantages Asex…

Sexual Reproduction Sexual reproduction is a type of reproduction in which the two sexes, namely, male and female are involved. It incorporates a process of combining DNA from two different individuals during reproduction. DNA Content Re-establishment i…

Accumulation of Variation During Reproduction Heredity can be defined as resemblances among individuals related by descent or the transmission of traits from parents to the offspring. It means continuity of features from one generation to the next. Vari…

Heredity Genetics is the branch of biology which studies heredity and variation. Inheritance is the transmission of genetically controlled traits from one generation to the next Inherited Traits The traits or characteristics that are transmitted from on…

Evolution We have seen that there is an inbuilt tendency to variation during reproduction, both because of errors in DNA copying and as a result of sexual reproduction. A rare variation can become a common characteristic in a population when the freque…