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'.
Radiometric dating--the process of determining the age of rocks from the decay of their radioactive elements--has been in widespread use for over half a century. There are over forty such techniques, each using a different radioactive element or a different way of measuring them. It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.