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.

(i) Stabilizing selection (centripetal selection):
1. This type of selection operates in a stable environment.
2. The organisms with average phenotypes survive where as the extreme individuals from both the ends are eliminated.
3. There is no speciation but the phenotypic stability is maintained within the population over generation.
4. For example, measurements of sparrows that survived the storm clustered around the mean and the sparrows that failed to survive the storm clustered around the extremes of the variation showing stabilizing selection.
(ii) Directional selection:
1. The environment which undergoes gradual change is subjected to directional selection.
2. This type of selection removes the individuals from one end towards the other end of phenotypic distribution.
3. For example size differences between male and female alike extremely but different in body weight.
4. Females show directional selection in reflection to body weight.
(iii) Disruptive selection (centrifugal selection)
1. Under homogenous environmental changes into heterogenous environment this type of selection is operational.
2. The organisms of both the extreme phenotypes are selected whereas individuals with average phenotypes are eliminated. This results in splitting of the population into sub-population/species. This is rare form of selection but leads to the formation of two or more different species.
3. It is also called adaptive radiation (e. g.)  Darwin finches -beak size in relation to seed size inhabiting Galapagos islands.

1. Hugo de Vries by his experiment suggest that variations is caused due to mutation among the genetic sequence of an individual.
2. Hugo de vries for the first time gave the term saltation which stands for huge mutation in a single step resulting in speciation.
3. Darwin during his voyage in H.M.S. Beagle he found that living organism share similar features existed from million of years.
4. Evolution is a sequential process that leads to betterment of life forms to cope with change in environment and that is passed to successive generation called as natural selection.
5. Mutation is a random process and direction which is not specific.

1. There are five basic processes that affect the Hardy-Weinberg equilibrium and cause variations at genetic level.
2. These include (i) Mutation (ii) recombination (iii) Gene migration (iv) Genetic drift and (v) natural selection.
3. Among the above five processes, lets discuss how mutation, natural selection and genetic drift affect Hardy Weinberg equilibrium.
(a) Mutation:
1. Mutation are sudden heritable changes in the characteristics of the organisms.
2. These mutations are random (indiscriminate) with respect to the adoptive needs of organisms.
3. Most mutations are harmful or with no effects (neutral) on their bearers.
4. However under changed environmental conditions, the alleles, which were previously harmful or neutral may become advantageous.
5. The rate of mutation is very slow usually one mutation occurs in a million still these mutation rates are sufficient to create considerable genetic variation.
6. Mutations help in maintaining variations within population.
7. Mutation also introduce new genes and alleles into the gene pool (sum total of all genotypes or alleles found in a population).
8. It is the gene pool in which new genes are added or removed. This variability of genes (or) alleles in a gene pool, then serve as a raw material for evolutionary changes.
9. The accumulation of many mutations over hundreds of generation cause large scale changes.
(b) Natural selection
1. Natural selection is the most important evolutionary process that brings about changes in allele frequencies.
Definition
1. The process of differential reproduction that lead to differential contribution of genotypes to the gene pool of the next generation.
2. Natural selection results a change in allele frequencies of a population.
(c) Genetic drift
1. It refers to the elimination of certain genes in a small isolated population either due to intensive inbreeding causing permanent fixation of some genes or death of a small section of population by natural calamity.
Definition
1. The random changes in the allele frequency occurring by chance alone are called genetic drift.
2. This means that the alleles that form the gene pool of the next generation are a sample of the allele from current generation.
3. Sampling errors (chances) often lead to the elimination of certain alleles and fixation by others thus reducing the genetic variability of the population.
4. The effect of genetic drift is very small in large but can be large in a small population.
5. Thus these forces that change the allele and genotypic frequencies in a population and so called evolutionary agents.
6. As long as Hardy-Weinberg Equilibrium remains constant the evolution cannot occur since the genetic equilibrium is a sort of inertia whose tendency is rather conservative. Evolution become possible only if the inertia is overcome or the equilibrium is broken.

(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.

1. Fitness according to Darwin refers ultimately and only to reproductive fitness
2. Those individuals who are better fit in an environment leave more progeny than the others the populations come to posses more fit individuals as nature selects for fitness.
3. The so called fitness is based on characteristics which are inherited hence there must be. genetic basis for getting selected and to evolve.

(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.,