"Spotlight," the quiet procedural drama about the Boston Globe's exposé of sex abuse in the Catholic Church, won best picture Sunday night at the 88th Academy Awards, which was otherwise dominated by louder epics "Mad Max: Fury Road" and "The Revenant" - the latter yielding a much-anticipated best-actor win for Leonardo DiCaprio - and by running commentary on the lack of racial diversity among nominees and the movie business at large.

"This film gave a voice to survivors and this Oscar amplifies that voice, which we hope will become a choir that will resonate all the way to the Vatican," said "Spotlight" producer Michael Sugar onstage at the Dolby Theatre in Hollywood.

Mexican filmmaker Alejandro G. Iñárritu, who won for "The Revenant" and became the first back-to-back best director since 1951, also used his speech to call for social progress and to honor the abused and discriminated.

"What a great opportunity to our generation, to really liberate ourselves from all prejudice and this tribal thinking," said Iñárritu, who won last year for "Birdman" and whose latest film is about the brutal conquest of American land in the 1800s.

Host Chris Rock devoted nearly all of his irreverent opening monologue to the subject of race, joking that the only reason black people complain about the Oscars is because they've moved beyond earlier, bigger struggles.

"When your grandmother's swinging from a tree," said Rock, wearing a blinding white tuxedo jacket, "it's really hard to care about best documentary foreign short."

Upon winning his award near the end of the evening, DiCaprio received a robust standing ovation and delivered a gracious speech that climaxed with a call to arms against environmental degradation.

"Climate change is real - it is happening right now," said DiCaprio, who lost his first Oscar in 1994 when he was 19 years old and won Sunday after his fifth acting nomination for a role in which he plays a fur trapper who survives a bear mauling and then exacts revenge on the men who left him to die.

"It is the most urgent threat facing our entire species and we need to work collectively together and stop procrastinating."

The presenters and show participants were far more diverse than the acting nominees, all 20 of whom were white for the second year in a row. Angela Bassett, Whoopi Goldberg and Tracy Morgan were enlisted to defuse the controversy by making light of race in humorous video clips. Bollywood star Priyanka Chopra presented best film editing, and South Korean actor Byung Hun Lee awarded best foreign language film to Hungary's "Son of Saul." Robots C-3PO and R2D2 pointed out composer John Williams, nominated for the 50th time, for "Star Wars: The Force Awakens."

"The problems of today will one day be the problems of old," said presenter Kevin Hart, the actor and standup comic, adding, "Let's not let this negative issue of diversity beat us."

"Mad Max: Fury Road," a female-driven action-adventure film shot in the Namibian desert, was the big winner of the night with six awards, sending a parade of Australians to the stage to pick up Oscars for editing, costume design, production design, sound editing, sound mixing, and makeup and hairstyling.

The first surprise didn't arrive until two hours into the long ceremony, when Broadway mainstay Mark Rylance won best supporting actor for "Bridge of Spies" over Sylvester Stallone, who was favored for his reprisal of Rocky Balboa in "Creed."

The evening was punctuated by intense political moments, especially in its latter half. Vice President Joe Biden, who received a standing ovation, introduced Lady Gaga to perform best original song nominee "Til It Happens to You," from the documentary "The Hunting Ground," about sexual assault on college campuses.

Biden asked the audience and viewers to take "a pledge that says, 'I will intervene in situations when consent has not or cannot be given.' Let's change the culture."

Survivors of sexual assault joined Lady Gaga on stage during the song, their forearms showing "SURVIVOR" and "NOT YOUR FAULT" written in marker.

Costume designer Jenny Beavan, wearing a jacket bedazzled with "Mad Max" symbols, said that the toxic world of her film could be prophetic if we don't "stop polluting our atmosphere." Journalist Sharmeen Obaid-Chinoy won best documentary short for "A Girl in the River: The Price of Forgiveness," about honor killings in her native Pakistan.

"This is what happens when determined women get together," Obaid-Chinoy said, raising her statuette.

Swedish actress Alicia Vikander won the night's first acting award, for her supporting role as an artist in "The Danish Girl," a period drama about transgender pioneer Lili Elbe. The best-actress Oscar went as expected to 26-year-old Brie Larson, who played a woman held in sexual captivity in "Room," based on the best-selling novel by Dublin-born writer Emma Donoghue.

The best original screenplay award went to Josh Singer and Tom McCarthy for "Spotlight," while the adapted screenplay award went to Adam McKay and Charles Randolph for "The Big Short," the erratic tragicomedy about the 2008 housing crisis.

"The Revenant," which led all films with 12 nominations, won three total. In addition to the wins by DiCaprio and Iñárritu, Mexican cinematographer Emmanuel Lubezki took home his third consecutive Oscar. Film composer Ennio Morricone won his first competitive Oscar, for scoring Quentin Tarantino's "The Hateful Eight," and delivered his speech in Italian.

"Grazie," said the 87-year-old legend, after receiving a standing ovation.