Plant breeding or crop improvement : Plant breeding is an applied branch of Botany which deals with the improvement of crops and production of new crop varieties which are far superior to the existing varieties in all characters.Aims of Plant Breeding1. To increase the yield of crops.2. To improve the quality of crops3. To develop […]
Origin of lifeMany theories of “Origin of life” have been propounded by several researchers which are as follows—(1) Special creation theory : God created universe in six days. This theory was published in the ‘Bible’ in 16th century.First day Earth and heaven were createdSecond day Sky was createdThird day Dry earth and plants were madeFourth
Genetics : It is the science of heredity and the principles governing the inheritance of characters from parent to the progeny i.e., offspring is called genetics.Heredity : The process by means of which characters are transmitted from parent to the offspring is called heredity.Mendelism : Mendel’s peas experiment, valid analysis and deduction of laws of
GrowthIt is an autonomic process by which the synthesis of protoplasm results in the increase in size and weight. It is a basic property of all of living beings. The anabolic activities are far more than the catabolic activities. The cells of every living being undergo wear and tear. In some animals, some cells and
Female reproductive cyclesMammals are exclusively sexually breeder. The reproduction depends upon certain changes in reproductive organs and behaviour. The changes mainly consists of the sexual cycles (especially the female). There are two types of cycles exhibited by the mammals—(1) Menstrual cycle : Normally this cycle repeats after every 28 days. After 28 days the ova
Reproduction : Reproduction is the process by which an organism produces the same species.Types of reproduction :(a) Asexual reproduction(b) Sexual reproduction(A) Asexual reproduction : This involves the production of animals without any fertilization and zygote formation. This is of following types :(i) Binary fission : Amoeba, Euglena, Paramecium, Vorticella, Aurelia, etc.(ii) Multiple fission : Plasmodium,
Exocrine and Endocrine glands : These glands are secretory sites of the body. They are of two kinds—the exocrine and the endocrine glands. The exocrine glands convey their secretion to the place of their action via ducts whereas the endocrine glands secrete the active chemical messengers, the hormones and pour their secretion into the blood
Every living organism is sensitive and responds to changes in the external and internal environment of the body. The external and internal stimuli are received by varied types of receptors or sense organs. Every sense organ is supplied with the sensory nerve fibres which convey these stimuli to the C.N.S. These sense organs are grouped
Nervous system is responsible for complete control and co-ordination of the body and mind.Co-ordination : For the evolution of multicellular organism, it became absolutely necessary to develop certain system which may co-ordinate the functions among the different cells tissues and organs and may exchange the information between the changes in external environment and internal cellular
Skeleton systems are of following two types—Exoskeleton : This system remains on the surface of the body such as scales in fishes; wings, claws and feathers in birds; hair, teeth, horn and nail in mammals.Endoskeleton : This provides the main base and shape to the man. It is made up of bone and cartilage.Bones(a) Replacing
Nutrition : Nutrition is defined as the process in which breakdown of complex food materials into simpler substances and its subsequent absorption in the body takes place.Nutrients : The organic and inorganic substances which the living organism collects from the nature to carry out all the basic activities of the body are called nutrients.Minerals :
Locomotion : It is the act of movement which includes walking, running, crawling, hoping, flying or swimming freely, either on land or in liquid or in gaseous medium.Movement : It refers to the act of certain parts of the body in a particular direction.Types of muscle fibres(i) Skeletal muscle fibres.(ii) Smooth muscle fibres.(iii) Cardiac muscle
Excretion : It is the process that eliminates the waste products formed beacause of anabolism and catabolism of the body. Excretion involves the removal of nitrogeneous waste products from the body.Various waste products :Ammonia, urea, uric acid, bile pigments, excess salts and water are the waste products.Excretory organs : These are the organs which are
Circulatory System : It is a closed system of heart, arteries and veins which are used for transporting the blood to all parts of the body.Blood: It is a liquid connective tissue present in blood vessels inside the body. In its plasma the blood corpuscles or cells are floating.Plasma : It is a yellow straw
Respiration : Respiration is the process which involves the oxidation of food substances in the body to release energy. It is very important process.In respiration, there occurs exchange of gases, oxygen and carbon dioxide, between the body and the outside environment.Respiratory System : The various organs required for gaseous exchanges are said to form a