Class name Subject Book title Chapter number Content Created at
Class XII Biology Biology 4 as the males produce sperms by mitosis (Figure 4.13), they do not have father and thus cannot have sons, but have a grandfather and can have grands...
Class XII Biology Biology 4 it is evident that control crosses that can be performed in pea plant or some other organisms, are not possible in case of Figure 4.13 Symbols used...
Class XII Biology Biology 4 trait in question is dominant or recessive. Similarly, the trait may also be linked to the sex chromosome as in case of haemophilia. It is evident ...
Class XII Biology Biology 4 possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be at least carrier and the father should b...
Class XII Biotechnology Biotechnology 11 present in the system also depends on physicochemical conditions like pH, temperature, water, availability of oxygen and substrate, etc., of the en...
Class XII Biology Biology 4 result of this phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives. Accumulation of these in brain results in ...
Class XII Biology Biology 4 21. Similarly, Turner’s syndrome results due to loss of an X chromosome in human females. Failure of cytokinesis after telophase stage of cell divi...
Class XII Biology Biology 4 to sex Suchanindividualhasoverallmasculinedevelopment, chromosome composition in humans : however, the feminine development (development of breast,...
Class XII Biology Biology 4 tabular form known as ‘Punnett Square’. The factors (now known as gene) on chromosomes regulating the characters are called the genotype and the ph...
Class XII Biology Biology 4 (aneuploidy). This helped in understanding the mutational basis of genetic disorders. Down’s syndrome is due to trisomy of chromosome 21, where the...
Class XII Biology Biology 6 BIOLOGY CHAPTER 6 EVOLUTION 6.1 Origin of Life 6.2 Evolution of Life Forms - A Evolutionary Biology is the study of history of life forms Theory on...
Class XII Biology Biology 6 formed sometime later. The gases condensed under gravitation and formed the galaxies of the present day universe. In the solar system of the milky ...
Class XII Biology Biology 6 of amino acids. In similar experiments others observed, formation of sugars, nitrogen bases, pigment and fats. Analysis of meteorite content also r...
Class XII Biology Biology 6 different periods of history of earth. There has been gradual evolution of life forms. Any population Reprint 2026-27 EVOLUTION hasbuiltinvariation...
Class XII Biology Biology 6 study showed that life-forms varied over time and certain life forms are restricted to certain geological timespans. Hence, new forms of life have ...
Class XII Biology Biology 6 whereas analogy refers to a situation exactly Tendril opposite. Wings of butterfly and of birds look alike. They are not anatomically similar struc...
Class XII Biology Biology 6 a contrasting background’. During postindustrialisation period, the tree trunks became dark due to industrial smoke and soots. Under this condition...
Class XII Biology Biology 6 finches represent one of the best examples of this phenomenon. Another example is Australian marsupials. A number of marsupials, each differentfrom...
Class XII Biology Biology 6 in an otherwise hostile environment. Adaptive ability is 118 inherited. It has a genetic basis. Fitness is the end result of the ability to adapt a...
Class XII Biology Biology 6 the fact that population sizes in reality are limited, means that there had been competition for resources. Only some survived and grew at the cost...
Class XII Biology Biology 6 equilibrium. Sum total of all the allelic frequencies is 1. Individual (a) (b) 120 (c) Figure 6.8 Diagrammatic representation of the operation of n...
Class XII Biology Biology 6 selection is aprocessinwhichheritablevariationsenablingbettersurvivalareenabled to reproduce and leave greater number of progeny. A critical analys...
Class XII Biology Biology 6 evolved into reptiles. They lay thickshelled eggs which do not dry up in sun unlike those of amphibians. Again we only see their modern day descend...
Class XII Biology Biology 6 skills and self-consciousness. A rough sketch of the evolution of life forms, their times on a geological scale are indicated in (Figures 6.9 and 6...
Class XII Biology Biology 6 of Madhya Pradesh. Agriculture came around 10,000 years back and human settlements started. The rest of what happened is part of human history of g...