NCERT Class 12 Biology Strategies For Enhancement in Food Reproduction
STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION With ever -increasing population of the world, enhancement of food production is a major necessity.Biological principles as applied to animal husbandry and plant breeding have a major role in our efforts to increase food production…
NCERT Class 12 Biology Sexual Reproduction in Flowering Plants
SEXUAL REPRODUCTION IN FLOWERING PLANTS Are we not lucky that plants reproduce sexually? The myriads of flowers that we enjoy gazing at, the scents and the perfumes that we swoon over, the rich colours that attract us, are all there as an aid to sexual reproduction. Flowers do…
NCERT Class 12 Biology Reproduction in Organisms
REPRODUCTION IN ORGANISMS Each and every organism can live only for a certain period of time. The period from birth to the natural death of an organism represents its life span. Life spans of a few organisms are given in Figure 1.1. Several other organisms are drawn for which…
NCERT Class 12 Biology Reproductive Health
REPRODUCTIVE HEALTH You have learnt about human reproductive system and its functions in Chapter 3. Now, let’s discuss a closely related topic – reproductive health. What do we understand by this term? The term simply refers to healthy reproductive organs with normal functions…
NCERT Class 12 Biology Principles of Inheritance
PRINCIPLES OF INHERITANCE AND VARIATION Have you ever wondered why an elephant always gives birth only to a baby elephant and not some other animal? Or why a mango seed forms only a mango plant and notany other plant? Given that they do, are the offspring identical to their …
NCERT Class 12 Biology Organisms and Populations
ORGANISMS AND POPULATIONS Our living world is fascinatingly diverse and amazingly complex. We can try to understand its complexity by investigating processes at various levels of biological organisation–macromolecules, cells, tissues, organs, individual organisms, population,…
NCERT Class 12 Biology Molecular Basis of Inheritance
MOLECULAR BASIS OF INHERITANCE In the previous chapter, you have learnt the inheritance patterns and the genetic basis of such patterns. At the time of Mendel, the nature of those ‘factors’ regulating the pattern of inheritance was not clear. Over the next hundred years, the…
NCERT Class 12 Biology Microbes In Human Welfare
MICROBES IN HUMAN WELFARE Besides macroscopic plants and animals, microbes are the major components of biological systems on this earth. You have studied about the diversity of living organisms in Class XI. Do you remember which Kingdoms among the living organisms contain…
NCERT Class 12 Biology Human Reproduction
HUMAN REPRODUCTION Introduction As you are aware, humans are sexually reproducing and viviparous. The reproductive events in humans include formation of gametes (gametogenesis), i.e., sperms in males and ovum in females, transfer of sperms into the female genital tract (…
NCERT Class 12 Biology Human Health and Disease
HUMAN HEALTH AND DISEASE IntroductionHealth, for a long time, was considered as a state of body and mind where there was a balance of certain ‘humors’. This is what early Greeks like Hippocrates as well as Indian Ayurveda system of medicine asserted. It was thought that…
NCERT Class 12 Biology Evolution
EVOLUTION Evolutionary Biology is the study of history of life forms on earth. What exactly is evolution? To understand the changes in flora and fauna that have occurred over millions of years on earth, we must have an understanding of the context of origin of life, i.e.,…
NCERT Class 12 Biology Environmental Issues
ENVIRONMENTAL ISSUES Introduction Human population size has grown enormously over the last hundred years. This means increase in demand for food, water, home, electricity, roads, automobiles and numerous other commodities. These demands are exerting tremendous pressure on our…
NCERT Class 12 Biology Ecosystem
ECOSYSTEM Introduction An ecosystem can be visualised as a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. Ecosystem varies greatly in size from a small pond to a large forest or a sea. Many…
NCERT Class 12 Biology Biotechnology and Its Applications
BIOTECHNOLOGY AND ITS APPLICATIONS Introduction Biotechnology, as you would have learnt from the previous chapter, essentially deals with industrial scale production of biopharmaceuticals and biologicals using genetically modified microbes, fungi, plants and animals. The…