The danger of delving into academic lineages is that can (and sometimes does) reinforce insider-ism, distinguishing those with and without prominent scientists in their academic roots. One might certainly object to delving into history because of this possibility. Can't we just measure contemporary scientists by the novelty and rigor of the work they do? Vanity aside, is there a good reason to think about these things?
While it would be dishonest of me to deny any pride in my own academic heritage, which includes some very prominent scientists, I think the answer to the latter question is, Yes. Academic lineages help us remember that we are all of us standing on the shoulders of giants. They remind us that many ideas and approaches are old, and that the history of ideas, and the people who developed and evaluated them, continue to shape contemporary science. And they help us understand where whole disciplines and strains of thought arise. After all, 100 years ago ecology was barely a scientific discipline. Who were the (then mostly) men who shaped the application of scientific rigor to the study of natural history? Some lineages in ecology trace back to early physiologists, chemists, even theologians. How often do cross-overs occur in more recent times? With the present emphasis on interdisciplinarity, isn't this something we want to know more about?
So while it is crucially important to separate our assessment of scientists from assessments of their academic lineages, it is also essential to our understanding of how science and mentorship work to understand the basic facts of our own academic history.