Tag: natural selection

Osmosis is the movement of solvent from its higher concentration to its lower concentration across a semipermeable membrane. It does not affect the solute particles and does not facilitate their movements. Thus osmosis does not affect the movement of dissolved substances into roots and through the plant.

In a fully turgid cell, water diffuses into the cell causing the cytoplasm to build up pressure against the wall. This pressure is called turgor pressure.

DPD or diffusion pressure deficit is the difference in the diffusion pressure of a solution and a pure solvent when both are subjected to the same atmospheric pressure. Since pure solvent has no dissolved solutes in it, therefore it will have maximum diffusion pressure and zero DPD.

Ernst Haeckel formulated his theory as "Ontogeny recapitulates phylogeny". “Ontogeny recapitulates phylogeny” was a commonly used phrase to explain the evidence supporting evolution. Ontogeny is “the complete developmental history of the individual organism,” and phylogeny is defined as “the complete evolutionary history of a group of organisms,”. Thus, this phrase means that the evolutionary history of a group of organisms is repeated during the developmental history of an individual organism of that group. This idea is also known as recapitulation. 

The primitive atmosphere of earth was reducing atmosphere with no oxygen but was rich in water vapour, carbon monoxide, carbon dioxide, nitrogen and hydrogen. Owing to immense long lasting rainstorms, a tremendous amount of lightening was generated. Lightening provided energy for chemical reactions between hydrogen and nitrogen and carbon to form ammonia and methane. So, the correct answer is option A.  

An imperative proof for natural advancement is the event of homologous and minimal organs. Homologous organs are those which have the regular inception and are based on a similar central example yet they perform diverse capacities and have distinctive appearances, e.g. whale's flipper, bat's wings, feline's paws, steed's front legs, fledgeling's wings, bull's front legs, and human hands.

Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. As the natural selection a process in which organisms with certain inherited traits are more likely to survive and reproduce than are individuals with other traits. So natural selection is a differential reproductive success as it acquires useful

Nucleic acids were formed in a primitive hot soup of sea by the formation of pyrimidine-sugar –phosphate and purine-sugar-phosphate. RNA has the ability of self replication and to catalyze other chemical reactions. Thus, RNA served as an enzyme as well as genetic material in first life forms. Amino acids were formed by condensation, polymerization and redox reactions of hydrocarbons, ammonia and water in Primitive Ocean under influence of energy from UV rays, radiations and lightening. RNA catalyzed polymerization of these amino acids formed polypeptides. The nucleic acid came before proteins. Urea was synthesized as excretory material much later during the evolution of land animals as ammonia is very toxic and requires more water to serve as excretory material. Thus, the correct answer is option B.