Crosswords0 min ago
Is there anything new?
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No best answer has yet been selected by amarillis. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.In the main, yes, everything has been here since the formation of our planet.
All the physical and biological processes occuring on the Earth, (from eruptions of volcanoes to erosion of mountains, the birth of a rat, to digesting a McDonalds) are chemical reactions, where matter is neither created nor destroyed.
As you say, the atoms are 'recycled' as one molecule breaks down or reacts with another to form something else.
The only way new atoms can be created is in some form of nuclear process.(Don't automatically think 'nuclear explosion')
This occurs naturally as 'radioactive decay' where (briefly) some elements are 'unstable' and the atoms themselves break down to become one or more different atoms.(Uranium-238 (that is its atomic number) decays to Thorium-234 and eventually to Lead ) This is a whole thread in itself.
The man-made processes occur in nuclear reactors where atoms break down ('nuclear fission') to form new ones, whilst some 'new' atoms are created in laboratories - the 'man-made elements' since they don't exist in nature.
All these different elements themselves (the naturally occurring ones, at least) were created in stars that have long since gone. Stars are massive fusion reactors, where small atoms are fused together at high temperatures to create heavier elements - hydrogen into helium, helium into carbon and oxygen etc. As one star explodes and dies, the matter ejected forms into a new star and the fusion process goes on creating all the elements.
It is from some of this 'stellar dust' that the Earth and our solar system (and galaxy) was formed.
Whatever the case, I'd say mutations also need to be taken into account of our changing world. How these mutations occur, and why? I haven't the slightest clue. I guess genes, bacteria, unicellular org's, DNA strands, etc. behave much like humans: they don't like to stay in the same shape or form for very long.
it's all just recycled molecules, basically
also, chaotic1, "Some people I suppose even think that mutations are the primary cause of evolutionary change" hell some people would be right, i guess! mutations occur, if this mutation turns out to be beneficial, the subsequent generations whom the mutation affect survive longer & prosper so have more offspring, and so now the mutation becomes "normal"