NonLin…
Any Christian would, almost certainly, consider the Soul - God’s gift to each person - to be the Essence of Life.
BioLogos is devoted to Christians… so you are probably using the wrong subject title for your BioLogos audience.
Maybe @Jonathan_Burke and @T_aquaticus can comment on this “Essence of Life” theme.
The comment “peppered moth is a genuine example of evolution” is a reference to the definition of Evolution which includes even changes in allele ratios!.. not just the arrival of some novel mutation.
As for the definition of species, for once the Bible and the Scientists are actually on the same page:
These two verses, made famous by the Rev. Kent Hovind, clearly define what God meant by ‘kinds’!:
Gen 1:24-25
"And God said,
Let the earth bring forth the living creature after his kind,
cattle, and creeping thing, and beast of the earth after his kind:
and it was so. "
“And God made
the beast of the earth after his kind,
and cattle after their kind,
and every thing that creepeth upon the earth after his kind:
and God saw that it was good.”
Now, speciation generally cannot occur until the free exchange of genetic material within a group is interrupted by geographical barrier (sometimes a behavioral change acts as such a “barrier” like a new bird song that is only attractive to a relatively small group of bird mates). Once the free exchange of genetic material within a group is interrupted, one group can experience gene pool changes that the other group does not experience - - or doesn’t experience in the same way.
And once the two populations start heading in their own unique directions, you can have one group getting bigger or smaller, while the original group is getting hairier or less hairy… horns appear… or disappear… diet changes - - any change can happen.
While this speciation does not mean two groups suddenly look dramatically different … the very next step in the process of speciation is one group “drifts” towards a new “optimum” fit - - while the original group “drifts” towards in yet another extreme or optimum “fit”. Eventually, we have fish with limb like fins… or proto-whales with dwindling limbs… or rodents that start developing extra expanses of skin to assist in their travel between tree stands - - on its way to being a bat.
In plants, speciation can happen in a single generation when chromosomes double-up … and reproductive compatibility is re-defined in a single season!!!