Serving Quality Education
Serving Quality Education
Environmental Issues, Class 12, Biology, CBSE 2 Environmental Issues Causes of air pollution The main causes of air pollution are as follows:(a) Exhaust from Automobiles: Most of the automobiles use fossil fuels. Burning of fossil fuel releases carbon dioxide and…
1 Theories of Origin of Life and EvolutionTheories of Origin of Life(i) In previous days, people believed that the universe and life on it was an act and result of God’s creation.(ii) There was, however, no evidence to support these…
– All formulas of the chapter at one glance. 1 Hardy-Weinberg Equilibrium Hardy-Weinberg principle states that the genetic constitution in a population remains constant if there is no external influence. This statement gives us a formula that is used to solve…
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1. Comparative morphology and anatomy of individual organ and organ systems of diverse forms of organisms reveal their phylogenetic relationships and thus provides important evidences of evolution.2. Homology is a relationship defined between structures or DNA derived from a common…
The following are the stages of human evolution: 1. Dryopithecusi) Ancestors of both man and apes. ii) Lived in China, Africa, Europe and India. iii) Predominantly herbivores2. Ramapithecusi) First remains were discovered from the Shivalik range in Punjab and later in Africa and Saudi…
Founder effectIt is the effect on the resulting gene pool that occurs when a new isolated population is founded by a small number of individuals possessing limited genetic variation relative to the larger population from which they have migrated.Sewall wright effectThe…
1. The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.2. The Hardy-Weinberg equation is expressed as: p2 + 2pq + q2 = 1 where p is…
The salient features of mutation theory are as follows:1. Mutations or discontinuous variations are the raw material of evolution.2. Mutations appear all of a sudden. They become operational immediately.3. Unlike Darwin’s continuous variations or fluctuations, mutations do not revolve around…
Natural selection is of three types directional, stabilizing, and disruptive selection.1. Directional selection occurs when natural selection favors one extreme of continuous variation. Over time, the favored extreme will become more common and the other extreme will be less common or lost.3. Stabilizing…
Adaptive radiation is evolutionary divergence of members of a single phyletic line into a series of rather different niches or adaptive zones.
Comparative study of the embryos of different animals show a great deal of similarity.
Miller-Urey experiment 1. In the 1950’s, biochemists Stanley Miller and Harold Urey, conducted an experiment.2. It demonstrated that several organic compounds could be formed spontaneously by simulating the conditions of Earth’s early atmosphere.3. It was a chemical experiment that simulated the…
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Semi-Conservative Replication of DNA – Meselson & Stahl’s Experiment Meselson and Stahl demonstrated that DNA replicated semi-conservatively, which means that each strand in a DNA molecule serves as a template for synthesis of a new, complementary strand. Watch this video THE…
Proof of DNA as the Genetic Material – Experiment of Avery, MacLeod, and McCarty Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA (and not proteins) can transform the properties of cells, clarifying the chemical nature of genes. Avery, MacLeod…
Discovery of DNA as the Genetic Material – Hershey-Chase Experiment In 1952, Alfred Hershey and Martha Chase made an effort to find the genetic material in organisms. Their experiments led to an unequivocal proof to DNA as the genetic material. Bacteriophages (viruses…
DNA replication DNA replication is a process which occurs inside nucleus and requires various enzymes which help to manage this typical process. It is really difficult to learn the name, working order, and functions of these enzymes. But now you can…
Lac Operon Watch this video Gene Regulation and the Order of the Operon – YouTube
Codon chart Watch this video How to Read a Codon Chart – YouTube