Tag: natural selection

Total of specialized protoplasm other than germplasm in individual body or protoplasm of somatic cells is termed as somatoplasm. Germplasm is protoplasm of germ cells (egg and sperm cells) or any living tissues with the capability of generating new organisms. The germplasm is inherited from parents to offspring along with gametes; thus any mutation in germplasm is passed to progeny which is a requisite for successful mutation; option B is correct. Since somatoplasm is not passed to offspring, any mutation in it affects that individual only and is not passed to offspring which makes option A incorrect. The liquid phase of cell nucleus which harbours the nucleolus and chromatin and other structures is called as karyolymph. Similarly, the mutation in zygote affects single individual that develops from that zygote. Option C is incorrect. The granular endoplasmic reticulum that has studded ribosomes on its surface is called as ergastoplasm which is not inherited to offspring and thus is not suitable for successful mutation; option D is incorrect. Correct option B is correct. 

A sudden, inheritable, discontinuous variation due to change in chromosomes and genes is called Mutation. It is hereditary. Mutations in somatic cells are not hereditary.

So, the correct option is ‘somatic’.

Somaclonal variations are genetic variations observed in plants regenerated from tissue culture.

Ernest Haeckel is the scientist who had contributed much to genetic evolutionary studies. He is the one who described: "Ontogeny recapitulates phylogeny".

Species dominance refers to the condition where one or a few species are found in much greater abundance than others in a community. Species richness refers to the total number of species, while species evenness refers to the relative abundance of different species.

Organic compounds essential for life can be produced by simple inorganic constituents that were the conclusion first derived by Miller and Urey on the basis of their experiment. They took the gases thought to be present in the primitive atmosphere in a sealed flask and exposed them to electric spark. Later on analysis of flask, many organic compounds could be recovered.

The first organisms that appeared on earth resembled single-celled life forms called archaea that can live in extreme environments such as hot springs and deep-sea vents. They were prokaryotic heterotrophs and used inorganic chemicals from the environment for carbon fixation and this process is called chemoautotrophy. They were anaerobic in nature because free oxygen was absent during primitive environment on earth.

The earliest living organisms were prokaryotes which later on evolved to give rise to eukaryotes and photosynthesizing organisms.

• The giant nucleoprotein molecules were formed by the union of nucleic acid and protein molecules. These nucleoprotein particles were described as free-living genes. Nucleoproteins gave most probably the first sign of life.
• Hence Nucleoprotein gave most probably the first sign of life.
• So, the correct answer is 'Life'.