QUOTE
8. An organism that is more fit to survive is more likely to survive, especially if "fit" is defined as "more likely to survive".

9. An organism that is more fit to reproduce is more likely to reproduce, especially if "fit" is defined as "more likely to reproduce".
UNQUOTE

In Formal Logic, this is called 'circular reasoning' and Real Science avoids this, when it is detected. Also falls under 'Law of Fives', because what is to be proved is defined as existing at the start.