Tag Class 12

Evolution-Notes

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…

Evolution-Formulas

– 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…

Evidences from morphology and anatomy

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…

Stages in Human Evolution

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…

Hardy-Weinberg principle

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…

Mutation theory of Hugo de Vries

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…

Miller-Urey experiment

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…

Semi-Conservative Replication of DNA

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…

DNA replication-Process

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…

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