Friday night at City Center, seven members of the Alvin Ailey American Dance Theater capered on the beach, while also embodying the beach, in the world premiere of Uri Sands’s “Existence Without Form.” The common denominator animating the work’s various episodes was the balance of the natural world: The piece positioned itself at the interface of land and sea.

Mr. Sands has danced with the Ailey company, among several others, and also heads his own group, TU Dance, based in Minneapolis.”Existence Without Form,” was performed to a score of New Age keyboards, chamber strings, jazz, and intermitent vocalizing composed by Christian Matjias.

As “Existence Without Form” began, the dancers were assembled in a huddle, before starting to churn and sink and bend. They rolled or spiraled down to the ground, they stood on their hands. There was a tidalpool momentum to it all: Breakers reached the shore in waves of balletic assemblés. The dancers stood with their backs to the audience, magnetized by the horizon. There was a sponginess to their walk that suggested feet sinking into sand.

A woman in white stood apart from the group. She was erect when they were prone, a lone individual left standing. She was the still point around which they revolved. At times they seemed like a tribe of the dispossessed, and she was the most alienated, walking with her torso tilted to one side.

There followed a slow movement that tried to convey a profound slowness that might have been coral in the process of becoming. The woman in white was a loner no longer; she now danced with a man, on whom she piggybacked. He butted her or caught her in midair. She was limp at times, slung over her partner’s neck; their duet becoming a slowmotion tumbling routine that owed something to contact improvisation.

Next, two women came skidding onto the stage, skittering like sandpipers, cavorting to their hearts content. The sandpipers and everyone else returned to thread through the finale, which seemed rather inconclusive — but then tides don’t reach end stops; they ebb and flow.

“Existence Without Form” was on the mild side. At times the landscape seemed featureless. But it wasn’t boring, and Mr. Sands achieved a coherence by identifying a theme and sticking to it.

Friday night’s program opened with Ronald K. Brown’s “Ife/My Heart,” which was given its world premiere by the Ailey troupe last year. Here Mr. Brown succeeds in precipitating an authentic event onstage that ties together past and present, forebears and descendents, cultural cross-referencing and inheritances.

The nine dancers snake onstage clothed variously in African and Western garb, exuding the festiveness of guests at a wedding party. Processional equals conga line equals receiving line. The music is a mélange of electric gospel and polemical recitation.

The steps are often extraordinarily intricate by virtue of the articulations required of each dancer’s head, torso, and limbs, but there is an ostensible casualness to the whole thing that makes it seems like it is happening on its own, without intrusion or calculation on the part of the choreographer.

Friday night’s program closed with “Revelations,” which the Ailey troupe performs so often that the roles are shared by many different company members and contrasting interpretations come to the fore. On Friday, Matthew Rushing performed “I Wanna Be Ready” with almost elfin ardency that was completely different from the bristling delivery given by Amos J. Machanic at the season’s opening night 10 days earlier. And both dancers were completely persuasive.