Tips Lamarck oddly ignored, or Newton? (5)
I believe the answer is:
isaac
'newton?' is the definition.
(I know that newton given name Isaac)
'tips lamarck oddly ignored' is the wordplay.
'oddly ignored' means one should take alternating letters (letters in odd-numbered positions removed).
'tips'+'lamarck'='tipslamarck'
The alternating letters of 'tipslamarck' are 'ISAAC'.
'or' acts as a link.
(Other definitions for isaac that I've seen before include "Sacrificial offering" , "___ Newton, English physicist, d. 1727" , "Esau's father" , "Father to Jacob and Esau" , "Man's name" .)