There is, admittedly, something funny about a straight guy insisting he’s willing to have sex with January Jones out of a sense of duty to repopulate the planet. Yet the latest episodes of “The Last Man on Earth” also reveal this Fox series, in comedy terms, to be something of a dinosaur.

At the core of Sunday’s back-to-back installments (and SPOILER ALERT if you haven’t watched) is a very old concern about physical attractiveness – namely, what if you commit to one woman and suddenly some previously unattainable goddess walks into your life? That’s essentially the plight facing Phil (Will Forte), who agreed to “marry” Carol (Kristin Schaal) when he thought they were the only two people left alive, only to have Jones’ Melissa pop up, putting Phil on the horns of a moral dilemma.

The conceit would be less problematic, frankly, if the show didn’t go so out of its way to make Carol irritating and obnoxious. Even so, when Phil professed his “I’ve never felt this way before” infatuation with Melissa – after having finally convinced the pair that he needed to mate with both of them, for the sake of mankind – it was clearly predicated on nothing more than how Jones embodies the ideal of physical perfection.

The producers then ratcheted up the ante, in terms of the question of how appearance relates to attraction, by introducing another male, Todd (Mel Rodriguez), derailing Phil’s little fantasy. Moreover, the fact that Todd isn’t anybody’s idea of a Chris Hemsworth lookalike was offset by his saintly qualities, forcing Phil to keep trying futilely to one-up him.

In a way, “Last Man on Earth” (a title that’s now merely ironic) is frittering around the edges of something interesting, in the same way the season finale of HBO’s “Looking” (and more SPOILERS here) explored questions of fidelity, putting the central couple at odds over whether on-the-side sexual dalliances were a deal-breaker in their relationship.

Indeed, the most recent episodes of the Fox series owe a considerable debt to “The Heartbreak Kid,” the 1972 movie (and let’s forget about the remake) in which Charles Grodin plays a guy who meets Cybill Shepherd on his honeymoon and suddenly decides he’s made a terrible, terrible mistake.

Like Phil’s affection, however, thus far the show is only skin deep, leaving itself open to the kind of criticism leveled at it by the Huffington Post’s Maureen Ryan, who described the writing for Carol as “frequently awful and one-note … [casting] her into the thankless role of the hectoring woman who exists to remind a lead male character of rules, laws and social norms.” And with the addition of new characters, the series risks essentially morphing into “Gilligan’s Island,” if Gilligan spent all his time plotting to have sex with Ginger.

Fans might be tempted to say “lighten up,” and one can argue that the program’s goofy nature merits some creative latitude. Nevertheless, there is something deflating and shallow, in a “We’re still in1972” manner, about the execution of the premise – one where the message for men is that the worst thing that could possibly happen, even more than mass extinction, is being romantically tethered to a woman when someone who’s better looking comes along.