Bryson, Bill - On targeted extinction
Type of Spiritual Experience
There are a number of observations which relate to the strangely selective nature in which some more minor extinction events operate.
If we take another example, the KT meteor which it has been stated [and here I am relying on scientific hypotheses] wiped out the dinosaurs. A number of odd features seem to make it 'designed' to have done the job. First, it was enormous and struck with a force of 100 million megatonnes so its effects were worldwide. Second, it landed in a shallow sea just 10 metres deep at an angle and at a time when oxygen levels were 10% higher that they are now – as such the land was more 'combustible'. Third, the floor of the sea where it landed was rich in sulphur – the result of the impact was a sea floor the size of Belgium containing sulphuric acid and acid rain.
The effect of the impact was that dinosaurs were wiped out, but other reptiles – snakes, crocodiles, toads, newts, salamanders and other amphibians survived. Thus 'large' was removed and 'small' was preserved. In the sea, ammonites vanished – organisms which had probably reached their limit of functional enhancement - but nautiloids were not affected. Among plankton, 92% of foraminiferans were wiped out but organisms like diatons – important in subsequent increments - survived.
As Bill Bryson notes 'these are difficult inconsistencies'
A description of the experience
Bill Bryson - A Short History of Nearly Everything
In between the big kill-offs, there have also been many smaller, less well known, extinction episodes – the Hemphillian, Frasnian, Famennian, Rancholabrean and a dozen or so others – which were not so devastating to total species numbers, but often critically hit certain populations.
Grazing animals, including horses, were nearly wiped out in the Hemphillian event about 5 million years ago.
Horses declined to a single species.
The source of the experienceBryson, Bill
Concepts, symbols and science items
Creation and destruction
Great Work, the
Increments of evolution