I backtracked my gaze at many points. For example I backtraced my gaze at Lamarck. Then I backtracked my gaze at the word inherited in line 2 to read the line 1 once again. I backtracked my gaze for the longest time at the start of second paragraph. At the end of second paragraph I once again backtracked my gaze. So in short, I bactracked at the word - Lamarck (line 1), inherited (line 2), evolve (line 3), views of Lamarck (line 5), On the "Origin of Species" (line 6), others (line 10).

My fixations are longer on the word proposed (line 1), acknowledges Lamarck (line 9), full stop on last line, theory of organism constancy (line 8), turn out (8) and empty space on left side.

Firstly I am a slow reader and I have a habbit of reading lines over and over again to relate to my prior knowledge. For example, being an avid fan of french history I know many people whose name start with Jean-Baptiste so on reading Lamarck I probably tried to remember if I know about him. Then on reading the word inherited I tried to understand what he trying to say since inherit is a verb that provokes action and thinking. For the word views of Lamarck, I probably tried to recall what his views were - I do have a very short memory and tend to forget things quickly - and on reading the "Origin of Species" I tried to remember the name of the work of Lamarck also I thought that since we are jumping to a new topic so what was the summary of the previous topic (discussion of Larmack) hence I read the first para once again.
Similarly for words like proposed, acknowledge - these words provoke thinking and action so I think who proposed what, who acknolwledge whom etc. Also I tried to summarize the points at the end of text so my gaze there was longer, occasionally I have a habbit of relaxing my eyes by looking at empty space - I for example often look at empty walls while thinking - that probably explains longer gaze on white space on left. The word "theory of organism constancy " was a complicated name and it took time to understand what the theory is or could be hence again a longer gaze.