Origin and Evolution of Life

Overproduction, Struggle for existence, Organic variations

Darwin's theory is based on five main postulates: overproduction, struggle for existence, organic variations, natural selection, and origin of new species. Inheritance of acquired characters is Lamarck's theory, not Darwin's.

Methane (CH₄), Ammonia (NH₃), Water vapor (H₂O), Hydrogen sulfide (H₂S)

The primitive atmosphere was reducing in nature and contained methane, ammonia, water vapor, and hydrogen sulfide. It was devoid of free oxygen, which came later through photosynthesis.

Population is large, Mating is random, No mutations occur, Natural selection is absent

Hardy-Weinberg equilibrium requires a large population, random mating, no mutations, no natural selection, and no gene flow. Gene flow would change allele frequencies and disturb the equilibrium.

Reptiles and birds

Archaeopteryx shows both reptilian features (teeth, long tail, claws) and avian features (feathers, wings, beak), making it a connecting link between reptiles and birds.