PBS has acquired a patina of cool since “Downton Abbey” and “Sherlock” arrived, but public television can’t — and probably shouldn’t — shed its stodgy image. Cases in point are a pair of nonfiction series premiering within the next month, both centered around the stuffy, slightly ponderous form of the on-camera presenter: “The Story of the Jews,” Simon Schama’s five-hour dissertation on Jewish history; and “Your Inner Fish,” paleobiologist Neil Shubin’s three-part evolutionary trip through human DNA. Both have merit, but also feel like sort of doggedly pontificating exercises that practically dare viewers to sit through them, as opposed to inviting them in.

Already shown in the U.K., “Story of the Jews” is deeply personal, and too often profoundly dull. Part of that has to do with the amount of time Schama spends on screen — leisurely walking and talking, in soothingly sleep-inducing tones, through historic locales ­— approximating more the feel of having a front-row seat for a protracted lecture than a fully realized documentary.

Selectively wading through thousands of years of history (the documentary is derived from a related book, and feels like it), in this format Schama can’t help but be somewhat arbitrary in the topics he chooses to tackle. And while one can appreciate the desire to make this more than another revisiting of the Holocaust, as Schama notes early on, Jewish history is invariably “a story of suffering and resilience.”

The last couple of chapters (PBS will schedule the five hours over successive Tuesdays) are less focused than the first night, flitting from the Dreyfus affair in France to Jewish musicians like Irving Berlin in America. Finally, it culminates with the founding of Israel — where the people, he says, “exploded the stereotype of Jews as weak, rootless victims” — and examines questions regarding the nation’s future.

Schama is certainly a genial guide. But nobody will call this “Story” the greatest ever told.

“Your Inner Fish,” based on Shubin’s bestselling book, has a bit more going for it, if only because the hostility toward the teaching of evolution in certain evangelical circles has made the need for science-based programming more pronounced.

Shubin’s thesis, though — that there are fascinating clues about human ancestry buried in our DNA and the structures of our bodies — becomes a bit tedious as we follow him sifting through fossils around the globe, or interacting with students of human anatomy in Chicago.

The second and third installments (“Your Inner Reptile” and “Your Inner Monkey”) continue along these lines, with efforts to spice up the visuals, including computer renderings of ancient creatures. But even these do little to break up the monotony.

“Inner Fish” joins “Nature” and “Nova” as part of a science-oriented block dubbed “Think Wednesday.” While it’s nice that PBS makes such fare available in these frenetic times, truth be told these two additions to its nonfiction portfolio aren’t the kind of TV you watch, necessarily, but rather listen to while reading the newspaper.

Then again, for the older quadrants of the PBS demographic, maybe that’s what you call a “two-screen experience.”

TV Review: PBS’ ‘The Story of the Jews,’ ‘Your Inner Fish’

<p>(Documentary; PBS, Tue. March 25, 8 p.m.)</p><p>(Documentary; PBS, Wed. April 9, 10 p.m.)</p>

  • Production: <p>Produced by Oxford Film and Television for BBC and Thirteen in association with WNET.</p><p>Produced by Tangled Bank Studios and Windfall Films.</p>
  • Crew: <p>Executive producers, Martin Davidson, Nicolas Kent, Julie Anderson, Stephen Segalier; series producer/director, Tim Kirby; writer, Simon Schama. 120 MIN.</p><p>Executive producer, Michael Rosenfeld; producer-director, David Dugan. 60 MIN.</p>
  • Cast: <p>With: Simon Schama</p><p>With: Neil Shubin</p>
  • Music By: