Outline the method for dating rocks and fossils using radioisotopes
And whales are stretched-out land animals whose forelimbs have become paddles and whose nostrils have moved atop their head. 53) Such remodeling is also seen routinely in human technology.In any case, there are also many instances of convergent evolution, where anatomical and molecular similarities are not readily explicable by common ancestry since the traits emerged some time after the supposed split of the pertinent lineages.The record in the rocks confirms several predictions of evolutionary theory: gradual change within lineages, splitting of lineages, and the existence of transitional forms between very different kinds of organisms. 53) expected under common descent — such as the pattern of saltations followed by stasis, and the appearance of the higher metazoan taxonomic categories before the lower ones.The second lesson from the fossil record, according to Coyne, is that, [W]hen we find transitional forms, they occur in the fossil record precisely where they should., one may reasonably expect to see two coordinated mutations achieve fixation in the timeframe of around 43.3 million years.When one considers the magnitude of the engineering feat, such a scenario can only be ruled incredible.So, where this comes in for rocks is that the carbon in living organisms tends to get replenished with fresh (mildly) radioactive carbon and oxygen, matching roughly the abundance in the air and water surrounding the organism, until they die.
The legs of land animals are variations on stout limbs of ancestral fish.
And the undecayed half will have half-decayed in that interval again -- so if you wait twice the half-life, you will only have a quarter the amount remaining that you started with; three-quarters will have decayed.
You don't know WHICH three-quarters (down to specific atoms and predictions), but you know how many of them will have.
Lessons from the Fossil Record According to Coyne, there are three lessons to be learned from the fossil record.
The first one is that, [The fossil record] speaks loudly and eloquently of evolution.
You can also check them against each other and make sure your answer makes sense.