things vary naturally e g the moths some survive better e g the moths the surviver s variation is preserved more than those which survive less because the surviver survives more the net change is toward the better variation it has evolved into the kind with the newer variation it has another different variation less than 100 of the versions of which survive better only some of the new versions propagate the net change is towards the preferred version of this 2nd variation ditto for a 3rd variation ditto for a 4th variation ditto for a 5th variation ditto for a 6th variation ditto for a 7th variation ditto for a 8th variation ditto for a 9th variation ditto for a 10th variation ditto for a 11th variation ditto for a 12th variation ditto for a 13th variation ditto for a 14th variation ditto for a 15th variation it is now beyond similarity of the original state repeat for 1000 000 000 years