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Hardy-Weinberg's principle says that allele frequencies in a population are stable and constant from generation to generation. The gene pool remains constant. This is called genetic equilibrium. Sum total of all the allelic frequencies is 1. Individual frequencies, e.g. can be named p, q, etc. Natural selection disturbs the allelic frequencies. Through natural selection either the frequency of p increases or the frequency of q it will disturb the natural frequency. In a diploid, p and q represent the frequency of allele,A and allele a. The frequency of AA individuals in a population is simply p². This is simply stated in another ways, i.e., the probability that an allele A with a frequency of p appear on both the chromosomes of a diploid individual is the product of the probabilities.

Hence, p² + 2pq + q² =1

The factors that affect the Hardy-weinberg's equilibrium are : 

(i) Migration 

(ii) Gene flow 

(iii) Genetic drift 

(iv) Mutation 

(v) Genetic recombination

(1) (i) Mutation are random and inheritable. 

(ii) Same type of mutations may occur in a number of individuals of same species the first recorded mutations was short-legged Ancon sheep which appeared suddenly in the herd of Seth wright of Massachusetts in 1791. 

(2) Hornless polled hereford cattle appeared as mutation during 1889.

Characteristics of Neanderthal man: 

i. Their brain size was 1400 cc. 

ii. They used hides to protect their bodies. 

iii. They buried their dead

(i) There is no origin of life on the earth taking place today because the earth atmosphere is not reducing but it is oxidising.

(ii) The energy was provided by an electric discharge and by heating the water chamber and the products obtained in the experiment were amino acids. 

(iii) Solar radiations with UV-rays & lightning (electrical discharges) and other high energy rays etc. should have been the energy sources required for the origin of life on the earth. 

(iv) The values exhibited by the biology teacher Deepak Gupta are : 

(a) caring for his neighbours. 

(b) desire to disseminate knowledge as a teacher and 

(c) the sound knowledge of the subject.

(i) No, the belief of the people that insects and moths might have developed from the mud is wrong. The theory of origin of life in such a way is known as the theory of spontaneous generation or which was disproved by many scientists. 

(ii) Life comes from pre-existing life only. The insects have not developed abiogenetically but they have developed from the fertilized eggs lying in the mud. 

(iii) Values exhibited- 

- Awareness about the environment 

- Understanding 

- Disposal of myths and wrong belief prevailing in the society.

Hardy-Weinberg's principle says that allele frequencies in a population are stable and constant from generation to generation. The gene pool remains constant. This is called genetic equilibrium. Sum total of all the allelic frequencies is 1. Individual frequencies, e.g. can be named p, q, etc. Natural selection disturbs the allelic frequencies. Through natural selection either the frequency of p increases or the frequency of q it will disturb the natural frequency. In a diploid, p and q represent the frequency of allele,A and allele a. The frequency of AA individuals in a population is simply p². This is simply stated in another ways, i.e., the probability that an allele A with a frequency of p appear on both the chromosomes of a diploid individual is the product of the probabilities.

Hence, p² + 2pq + q² =1

The factors that affect the Hardy-weinberg's equilibrium are : 

(i) Migration 

(ii) Gene flow 

(iii) Genetic drift 

(iv) Mutation 

(v) Genetic recombination

Characteristics of Neanderthal man : 

(i) They possess a brain capacity of 1300 - 1600 cc. 

(ii) They were short but very strong, with outward-curved thigh bones. 

(iii) They used hides to Protect their body. They buried the dead.

(i) Change in allele frequency 

(ii)  New genes develop, old genes are lost

(iii) Migration

(iv) Drift

(v) New species

When section of population gets separated due to migration or genetic drift, gene frequencies changed ; sometimes this change in allele frequency is different in the new population so that they becomes new species, this is called founder effect.

Homo habilis were first human like hominid. They probably did not eat meat/vegetarian, and their brain capacities were between 650-800 cc.

Dryopithecus, Ramapithecus. 

They were hairy, walked like 

Dryopithecus is ape like 

Gorillas and Chimpanzees, 

Ramapithecus more man like,

Oparin and Haldane proposed that life originated from pre-existing non-organic molecules and the diverse organic molecules were formed from these inorganic constituents by chemical evolution i.e., formation of life was preceded by chemical evolution.

As described by Hugo de Vries the mutations are basis of origin of variations in the organisms.

Saltations (Mutation), large differences arising out all of a sudden in a population.

Ethiopia / Tanzania / Eastern Africa.

Saltation is a single step large mutation brings major change as speciation.

While working on evening primrose Huge de Vries put forward the idea of Mutation which he described as the large change arising out all of a sudden change in a population. It is believed that evolution is not due to minor heritable continuous variations as proposed by Darwin but this is mutation which cause evolution. According to Darwin the evolution is a gradual and slow, process but de-Vries believed that it is due to saltation single step large change called mutation and is a discontinuous process and it brings about speciation.

The hypothetical proposals given by Oparin & Haldane are : 

(i) Origin of life has taken place spontaneously from pre-existing non living organic molecules. 

(ii) Chemical evolution of life i.e. formation of life was preceded by chemical evolution.

Dryopithecus/Ramapithecus.

Cro-Magnon was the direct ancestor of living modern man.

(a) Evolution by anthropogenic action i.e., by human activities. 

(b) Adaptive radiation (convergent evolution).

This process of evolution from or formation of a number of divergent species from a common ancestor at a single point and in a given geographical area and the new species adapting, spreading or radiating in different directions is called adaptive radiation. Darwin'explained the phenomenon of adaptive radiation on the basis of his investigation of the basis of fauna of Galapogas islands Finches of Galapogas island offer the best example of adaptive radiation.

During his journey, Darwin went to Galapogas island, and observed, that there were many varieties of finches in the same island. They varied from normal seed-eating ones to those that ate insects. Another example of adaptive radiation is evolution of the Australian marsupials from a single ancestor.

Dryopithecus africanus.

Fossils are the remains of life forms of the part preserved in the rock. The study of fossils is called paleontology. Rock sediments of different ages contain fossils of different types. Early rocks contain fossils of simple organisms while recent rocks contain fossils of complex organisms and some contain extinct organisms. Study of fossils in different sedimentary layers indicate the geological period in which they existed and accordingly also indicate the evolutionary changes in the organisms.

Hence new forms of life evolved at different geologic times in the history of earth.

The process of evolution of different species from one species in a given geographical area starting from a point and radiating or spreading to other geographical areas or now habitats is called adaptive radiation. This is called as divergent evolution as this involves the formation of different functional forms of basically similar structures, e.g. Darwin's finches and Australian marsupials. However when more than adaptive radiation appeared to have taken place in different habitats of an isolated geographical area, the adaptive radiation can be referred to as convergent evolution. This involves the development of similar adaptive functional structures in unrelated groups of organisms e.g-. Australian marsupials and placental mammals- Placental wolf-Placental wolf and Tasmanian wolf.

(a) East Africa

(b) Homo erectus

(i) Industrial melanism (appearance of black peppered moths) 

(ii) Development of mutant varieties of mosquitoes resistant to DDT.

Analogy and homology of structures indicate the evidences of evolution from comparative study of morphology and anatomy of form, structure, relative position of different organs and their functions. Analogy indicates that similar environmental conditions and habitat result in the selection of similar adaptive features in different groups of organisms towards the similar function.

This shows the evolution of similar functional structures from unrelated organs. This is the result of convergent evolution. 

Homology includes the organs having similar structure origin and development, developed to have different forms so as to perform different functions in different groups of organisations. This phenomenon of producing functionally different forms from structurally similar organs is the result of divergent evolution. It indicates towards the Common ancestory.

Zosterophyllum ----> Ferns ----> Ginkgo ------> Gnetales

Paleontological evidences 

• The study of fossil is called paleontology. 

• Fossils are the remains or impressions of past organisms preserved in sedimentary rocks or other media. 

• Different-aged rock sediments in earth’s crust indicate the presence of fossils of different life forms which died during the sediment formation. 

• A variety of fossils ranging from the modern organisms to extinct organisms can be observed. 

• By studying the different sedimentary layers, the geological time period in which the organism existed can be predicted.

The thorn of Bougainvillea and the tendrils of Curcurbita and Pisum sativum represent homology. The thorn in former is used as a defence mechanism from grazing animals and the tendrils of latter is used as a support for climbing.

Industrial melanism: 

• In England, before industrialisation, white-winged moths were more in number than darkwinged moths. 

• But after industrialisation, dark-winged moths became more in number than whitewinged moths. 

• This is because during industrialisation, the tree trunks covered by white lichens became dark due to deposition of dust and coal particles. 

• As a result, white-winged moths could be easily picked up by predators from the dark background and dark-winged moths survived .

Chemical resistance: 

• Excessive use of herbicides and pesticides has resulted in evolution of resistant varieties of microbes in much lesser time scale. 

• As a result, pathogenic bacteria are appearing in very short period.

Excess use of herbicides, pesticides, etc., has only resulted in selection of resistant varieties in a much lesser time scale. This is also true for microbes against which we employ antibiotics or drugs against eukaryotic organisms/ cell. Hence, resistant organisms/cells are appearing in a time scale of months or years and not centuries. These are examples of evolution by anthropogenic action.

Fossils are remains or impression of hard parts of life-forms that existed in past. They are found in rocks. 

Study of fossils in different sedimentary layers indicates the geological periods in which they existed and showed that life forms varied over time.

(a) Adaptive radiation-The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) 

(b) Convergent evolution (Adaptive convergence) formation of functionally similar structures independently by unrelated organisms. 

(c) Wolf is a placental mammal, Whereas Tasmanian wolf is a marsupial mamma.

a. Adaptive radiation: It is the process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats). 

b. Tiger cat/banded ant eater/Marsupial rat 

c. Wolf is a placental mammal, whereas Tasmanian wolf is a marsupial mammal.

Louis Pasteur disproved the theory of spontaneous generation.