In assortative mating, individuals tend to choose mates similar to themselves; for example, large blister beetles tend to choose mates of large size and small blister beetles tend to choose small mates.
Though this does not alter allelic frequencies, it results in fewer heterozygous individuals than you would expect in a population where mating is random.
Although Cain denied being his “brother’s keeper,” we expect ethical standards and administered justice to function as a “brother’s keeper” to someone (especially ourselves).
Justice can be restorative (compensatory), requiring the wrongdoer to restore the innocent victim, to the extent possible, to the same (or a similar) condition the victim was in before the wrong was committed (such as paying to repair damaged property, paying hospital bills, returning stolen goods, etc.).
As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged.So, some caution might be in order before even long established theories are accepted as the "gospel truth", especially when some of the most famous scientists in the field start to question their own life's work.In considering the theory of human evolution it is interesting to note that some very well known scientists have actually suggested that the line of human evolution is far from clear.The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.They have masses of 13 and 14 respectively and are referred to as "carbon-13" and "carbon-14." If two atoms have equal numbers of protons but differing numbers of neutrons, one is said to be an "isotope" of the other.