i) Vestigeal organs  are those organs which are non–functional in the organism but were functional in their ancestors.

(ii) Variations : Is a process whereby closely related organism come to differ among themselves.

(iii) Neo–Darwinism : According to it, the unit of evolution is the population.

(c)

(a) Convergent Evolution : It is similar adaptations for survival in similar habitats. It is also called parallel evolution, e. g., Some Marsupials of Australia resemble placental mammals that live in similar habitats on other continents. Australia separated from other continents more than 50 million years ago. Marsupials arrived in Australia before it separated and evolved in isolation even before the placental mammals. Natural selection has favoured changes that made the two groups more similar. Their phenotypes have converged.

Divergent evolution is also referred to as adaptive radiation. In it the original form of organisms migrated to and adapted to a different environment in different areas. They gradually changed and formed new species. Darwin’s finches, homologous organs are good examples of divergent evolution e. g., the forelimbs of mammals i. e., the scale of Whale, wings of bat leg of a horse, human hand, though different superficially and perform different functions but they have almost same structure. This shows adaptive radiations or divergent evolution from a common ancestor.

(b) Manures are the organic wastes which after partial decay  are added to the soil to increase crop productivity.

Green Manure : Green manure consists of a quick growing crop which is cultivated and ploughed under the soil to provide organic matter and additional nitrogen to the soil.

Biofertilizers : Biofertilizers are organisms which bring about the nutrient enrichment of the soil.

(c) Integrated pest management is the selection, integration and implementation of pest control based on economic, ecological and sociological consequences.

Bioinsecticides – Bacillus thuringinsis

Bio herbicides – Cactoblastic cactorum or Phytophthora palmiora.

The biopesticidal approch mainly included sterilisation strategy.

They created probable conditions of primitive earth in the laboratory. They used spark discharge apparatus that had two tungsten electrodes to provide electric discharge (simulating lightning of primitive atmosphere). An atmosphere of gases (CH4, NH3, H2O, H2) was created in a chamber and condensed liquid allowed to accumulate in another chamber. Energy supplied by heating water in another chamber. After some days amino acids like glycine, alanine and some more complex organic compounds were collected in vitro like  purine, pyrimidine, sugar,glycerol, formic acid,short chain etc. This indicated the possibility of origin of life from inanimate matter on the earth, when atmosphere was reducing (containing no free oxygen), containing gases like methane, ammonia, hydrogen sulphide, frequent lightning and enough water was present. Simple amino acids which are building blocks of proteins might have given rise to complex molecules that are building blocks of cells.

(i) Frameshift mutations: Shifting of entire reading frame/caused either by addition or deletion of one or more nucleotide pairs in a molecule of DNA segment at one or more places OR diagrammatic representation

(ii) Genetic drift: The sudden and random changes in the allele frequency or gene frequency occurring in small population by chance alone.