Mutation theory was propounded by Hugo de Vries.
Chemical theory of evolution was propounded by Oparin and Haldane

Both the wings of cockroach and bird are different in structure but similar in their function. Thus, they are analogous structure that brings about convergent evolution.

Stabilizing selection
Directional selection
Disruptive selection

Gene Mutation, Chromosomal mutation, Genetic recombination, Natural selection, Reproductive isolation.

It is the study of prehistoric life through fossils

They argued that external conditions stimulate the somatic cells to produce certain 'secretions' which reach the sex cells through the blood and bring about variations in the offspring.

A slight change occurs over time in conserved molecules such as DNA, RNA, and protein. They are often called as molecular clocks and serve as molecular evidence of evolution.

(i) Neanderthal human was found in Neander Valley, Germany with a brain size of 1400 cc and lived between 34,000 - 1,00,000 years ago.
(ii) They differ from the modern. human in having semierect posture, flat cranium, sloping forehead, thin large orbits, heavy brow ridges, protruding jaws and no chin. 

(i) Darwin failed to explain the mechanism of variation.
(ii) Darwinism explains the survival of the fittest but not the arrival of the fittest.
(iii) He focused on small fluctuating variations that are mostly non-heritable.
(iv) He did not distinguish between somatic and germinal variations.
(v) He could not explain the occurrence of vestigial organs, over specialization of some organs like large tusks in extinct mammoths, oversized antlers in the extinct Irish deer, etc.,

Methane, carbondioxide, ammonia and water vapour.

Hardy of UK and Weinberg of Germany stated that the allele frequencies in a population are stable and are constant from generation to generation in the absence of gene flow, genetic drift, mutation, recombination, and natural selection.

Genetic drift is a mechanism of evolution in which allele frequencies of a population change over a generation due to chance (sampling error). Genetic drift occurs in all population sizes, but its effects are strong in a small population.

Genetic variation is the ALXl gene in the DNA of Darwin's finches is associated with variation in the beak shape. Mild mutation is the ALXl genes leads to phenotypic changes in the shape of the beak as in Darwin finches.

Artificial selection is a byproduct of human exploitation of forests, oceans, and fisheries or the use of pesticides, herbicides or drugs. For hundreds of years, humans have selected various types of dogs, all of which are variants of the single species of dog.

Mould	Cast
Even after disintegration, the body of an animal might leave an indelible impression on the soft mud which later becomes hardened into stones. Such impressions are called moulds.	The cavities of the moulds may get filled up by hard minerals and get fossilized, which are called casts.

The age of fossils can be determined using two methods namely, relative dating and absolute dating. (a) Relative dating is used to determine a fossil by comparing it to similar rocks and fossils of known age. (b) Absolute dating is used to determine the precise age of a fossil by using radiometric dating to measure the decay of isotopes.

The term evolution is used to describe heritable changes in one or more characteristics of a population of species from one generation to the other.

(i) The earliest fossils of the prehistoric man like Ramapithecus lived some 14mya. They were hairy and walked like gorillas and chimpanzees.
(ii) They had a brain capacity of 1300cc.
(iii) They lived on tough food consisting of seeds and savannah grasses and had well developed grains and heavy molars.
(iv) Australopithecus had a brain capacity of 461cc, teeth consisted of small canines and large molars. Good are softer foods consisting of grass, leaves and fruits.

Lamarcks 'theory of acquired character's was disproved by August Weismann who conducted experiments on mice for twenty generations by cutting their tails and Weismann proved that change in the somatoplasm will not be transferred to the next generation but changes in the germplasm will be inherited.

S.No	Divergent evolution	Convergent evoloution
1.	Divergent evolution is the evolutionary process in which the same structure develops in different directions in different groups of organisms as adaption to their different needs	Convergent evolution is the process in which anatomically different structures in different groups of organisms evolve towards same junctions and hence they have similarities
2.	Homologous organs are the result of divergent evolution	Analogous organs are the result of convergent evolution
3.	E.g: (i) Tendrils of Cucubits and thorns of bougainvillea	E,g (i) Sweet potato tubers (root modification) and potato tubers underground (stem modification)
4.	(ii) Fore limbs of man and the wings of birds	(ii) Flippers of penguins and those of dolphins
		(iii) Eyes of octopus and those of mammals

Sewell Wright, Fisher, Mayer, Huxley, Dobzhansky, Simpson and Haeckel explained Natural Selection in the light of Post-Darwinian discoveries. According to this theory gene mutations, chromosomal mutations, genetic recombinations, natural selection, and reproductive isolation are the five basic factors involved in the process of organic evolution.
i. Gene mutation refers to the changes in the structure of the gene. It is also called gene/ point mutation. It alters the phenotype of an organism and produces variations in their offsprings.
ii. A chromosomal mutation refers to the changes in the structure of chromosomes due to deletion, addition, duplication, inversion or translocation. This too alters the phenotype . of an organism and produces variations in their offspring.
iii. Genetic recombination is due to crossing over of genes during meiosis. This brings about genetic variations in the individuals of the same species and leads to heritable variations.
iv. Natural selection does not produce any genetic variations but once such variations occur it favors some genetic changes while rejecting others (driving force of evolution).
v. Reproductive isolation helps in preventing interbreeding between related organisms.

According to the theory of chemical evolution, primitive organisms in the primordial environment of the Earth evolved spontaneously from inorganic substances and physical forces such as lightning, UV radiations, volcanic activities, etc. Oparin (1924) suggested that the organic compounds could have undergone a series of reactions leading to more complex molecules. He proposed that the molecules formed colloidal aggregates or 'coacervates' in an aqueous environment. The coacervates were able to absorb and assimilate organic compounds from the environment. Haldane (1929) proposed that the primordial sea served as a vast chemical laboratory powered by solar energy. The atmosphere was oxygen free and the combination of CO₂, NH₃ and UV radiations gave rise to organic compounds. The sea became a 'hot' dilute soup containing large populations of organic monomers and polymers. They envisaged that groups of monomers and polymers acquired lipid membranes and further developed into the first living cell. Haldane coined the term prebiotic soup and this became the powerful symbol of the Oparin-Haldane view on the origin of life (1924-1929). Oparin and Haldane independently suggested that if the primitive atmosphere was reducing and if there was appropriate supply of energy such as lightning or UV light then a wide range of organic compounds can be synthesized.

Objections to Darwinism: Some objections raised against Darwinism were -
(i) Darwin failed to explain the mechanism of variation.
(ii) Darwinism explains the survival of the fittest but not the arrival of the fittest.
(iii) He focused on small fluctuating variations that are mostly non-heritable.
(iv) He did not distinguish between somatic and germinal variations.
(v) He could not explain the occurrence of vestigial organs, over specialization of some organs like large tusks in extinct mammoths, oversized antlers in the extinct Irish deer, etc.,

Lamarck's theory: Jean Baptiste de Lamarck, was the first to postulate the theory of evolution in his famous book 'Philosophie Zoologique in the year 1809. The two principles of Lamarckian theory are:
(i) The theory of use and disuse - Organs that are used often will increase in size and those that are not used will degenerate. Neck in giraffe is an example of use and absence of limbs in snakes is an example for disuse theory.
(ii) The theory of inheritance of acquired characters - Characters that are developed during the lifetime of an organism are called acquired characters and these are then inherited.

(i) According to the theory of chemical evolution primitive organisms in the primordial environment of the earth evolved spontaneously from inorganic substances and physical forces such, as lightning, UV radiations, volcanic activities, etc.
(ii) Oparin (1924) suggested that the organic compounds could have undergone a series of reactions leading to more complex molecules. He proposed that the molecules formed colloidal aggregates or 'coacervates' in an aqueous environment. The coacervates were able to absorb and assimilate organic compounds from the environment.
(iii) Haldane (1929) proposed that the primordial sea served as a vast chemical laboratory powered by solar energy. The atmosphere was oxygen free and the combination of CO₂, NH₃ and UV radiations gave rise to organic compounds.
(iv) The sea became a 'hot' dilute soup containing large populations of organic monomers and polymers. They proposed that groups of monomers and polymers acquired lipid membranes and further developed into the first living cell. Haldane coined the term prebiotic soup and this became the powerful symbol of the Oparin-Haldane view on the origin of life (1924-1929).
(v) Oparin and Haldane independently suggested that if the primitive atmosphere was reducing and if there was appropriate supply of energy such as lightning or UV light then a wide range of organic compounds can be synthesized.

Similarities found in Neanderthal man and Homo sapiens.
(i) They knew to protect their bodies. Neanderthal man used animal hides to protect their bodies.
(ii) They knew the use of fire.
(iii) They buried their dead.

Adaptive radiation is the process of evolution of different species in a given geographical area starting from a point and literally radiating to other geographical area habitats.
1. Darwins finches were the small black birds which Darwin observed in Galapagos islands.
2. There were many varities of these birds in the same island.
3. Darwin reasoned that after originating from a common ancestral seed eating stock the finches must have radiated to different geographical areas and undergone adaptive changes especially in their breaks enabling some of them to become insectivorous.
4. Living isolation for long new kinds of finches must have evolved which could survive in the new habitats.
5. Australian marsupials (Kangaroos) also show adaptive radiation
6. Marsupials in Australia and placental mammals in north America are two subclasses of mammals they adapted in similar way to a particular food resources, locomotary skill or climate.
7 They were separated from the ori-on ancestor more than 100 million year ago and each lineage continued to evolve independently despite temporal and geographical separation marsupials in Australia and placenta mammals in North America have reduced varieties of species living in similar habitats with similar way of life their overall resemblance in shape, locomotary mode, feeding and foraging are superimposed upon different modes of reproduction.