Relative dating is a method of determination of age, in which one object or organism is compared with the other object or organism found in the heap of strata. It is a method for determining the relative order of the past events, without stating the absolute age.
Stratigraphy is a branch of geology that studies the relative position of the sediments and rocks in the strata with respect to the geological timescale. Biostratigraphy is the branch of stratigraphy which deals with the relative aging of fossils with respect to the strata in which these are found defining a particular period of geological time scale.
The sickle form of the hemoglobin gene is created when an adenine nucleotide is changed to a thymine. ... That single amino acid replacement in the -globin protein alters the shape and the chemistry of the hemoglobin molecule, causing it to polymerize and distort the red blood cell into the sickle shape.
