pituitary dwarfism. caused by hyposecretion of growth hormone by pituitary gland at an early age, it slows growth and causes short and proportional stature; it is a congenital condition that can be treated during childhood with growth hormone therapy.aused by hyposecretion of growth hormone by pituitary gland at an early age, it slows growth and causes short and proportional stature; it is a congenital condition that can be treated during childhood with growth hormone therapy.
Molecular dating analyses allow evolutionary timescales to be estimated from genetic data, offering an unprecedented capacity for investigating the evolutionary past of all species. These methods require us to make assumptions about the relationship between genetic change and evolutionary time, often referred to as a 'molecular clock'.
Though relative dating can only determine the sequential order in which a series of events occurred, not when they occur, it remains a useful technique especially in materials lacking radioactive isotopes. Relative dating by biostratigraphy is the preferred method in paleontology, and is in some respects more accurate. The Law of Superposition was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.