reproduction and heredity

The modified form of cell theory is called cell principle. It applies almost completely and universally to living organisms. The cell principle is also called cell doctrine. Following are the statements of cell principle. Life exists only in cells. Living organisms may be composed of a single free ..

Chromosomal Basis of Inheritance - Heredity depends upon the protoplasmic continuity between the parent and the offspring. It is the gametes that establish the continuity between parent and offspring and hence, the mechanism of inheritance operates across this exceedingly slender protopla..

All around us we see different organisms belonging to different species. Within each species too, no two individuals are identical to each other. Variation may be defined as differences among individuals of a species. Asexual reproduction produces identical offspring called clones and id..

Parthenogenesis is a form of reproduction in which the ovum develops into a new individual without fertilisation. Natural parthenogenesis has been observed in many lower animals (it is characteristic of the rotifers), especially insects, e.g., the aphid. In many social insects, such as th..

The plant hydrangea can have pink "flowers" or blue "flowers" (they're actually modified leaves). But we do not classify the two forms as different species. In fact, one could allow a blue-"flowered" plant to become a pink-"flowered" plant just by changing the pH of the soil and the amount of alumi..

Parthenogenesis and Tissue Culture - Parthenogenesis is a form of reproduction in which the ovum develops into a new individual without fertilisation. Natural parthenogenesis has been observed in many lower animals (it is characteristic of the rotifers), especially insects, e.g., the aphi..

. Organisms with hard parts - shells, carapaces and skeletons appeared. The first fish and the first vertebrates appeared; plants, previously restricted to the oceans, began the colonization of the land; the first insect evolved, and its descendants became the pioneers in the colonization of the la..