7 songs that mattered in the '70s

(CNN)The Vietnam War. Racial tensions. Inflation and unemployment. Environmental calamity. The battle over women's equality.

If you're been watching CNN's "The Seventies," you're seen firsthand how, in the 1970s, America was "one nation under change."
The anxieties and issues of the decade were reflected in the pop culture of the time, including the era's music.
Here are five songs that speak to the issues of the era, plus two more that matter not for what they say but how they sound.

Marvin Gaye asks 'What's Going On" (1971)

"Father, father, we don't need to escalate/You see, war is not the answer for only love can conquer hate"
"What's Going On" transplants the soul of Motown into an existential, reactionary song: reactions to the Vietnam War, police brutality, stereotypes and racial profiling, and the general chaos of the '70s on a universal level.
Marvin Gaye held up a mirror to the confusion in the social and cultural landscape of the decade by asking a simple yet profound question. Gaye's query is not just rhetoric: the song is a call for action and real answers.

The frustration of a generation rings out: The Clash's "London Calling" (1979)

"The ice age is coming, the sun's zooming in/Engines stop running, the wheat is growin' thin"
England, too, had a tough time in the 1970s.
Years of massive inflation and rising unemployment, followed by trade-union strikes that left London in dysfunction and disrepair. And in 1978-79, one of the coldest winters in decades.
There seemed to be no end to the misery. Enter punk rock.
Punk was born as an outlet for the frustrations and anxieties of a generation that had seen the chaos of the decade play out on their TV sets.
It lived largely on the margins until The Clash's "London Calling" helped bring punk to the masses. The lyrics make reference to a litany of crises -- brutality, addiction, hopelessness, and, most notably, environmental Armageddon.
"London Calling" is a response to the bedlam, a declaration of outrage from disaffected but not disengaged youth.

Women's lib gets an anthem: Helen Reddy's "I Am Woman" (1971)

"I am strong. I am invincible. I am woman"
The efforts of Gloria Steinem and the Women's Liberation Movement spanned decades, but the fight for the ERA and the congressional hearings of 1970 brought feminism to the mainstream.
"I Am Woman" was written to fill a serious void in the market and Reddy's personal eagerness to hear a song that spoke to the female experience.
It soon became the unofficial anthem of the movement.
The straightforward lyrics are not particularly nuanced, but they offer a clarion call for a generation of women ready to fight for equal rights.

Gender-bending pop: The Kinks' "Lola" (1970)

"Girls will be boys and boys will be girls/It's a mixed up, muddled up, shook up world"
The sexual and gay rights revolutions of the '60s gave rise to more fluid gender roles in the decade that followed.
David Bowie sang "she's not sure if you're a boy or a girl" on his 1974 single "Rebel Rebel." Elton John came out as bisexual in a 1976 Rolling Stone interview.
The Kinks' story of a naive runaway and the presumably transgendered Lola is nonchalant and lighthearted.
It doesn't seem intended to make a political statement, but its open, casual approach to sexuality and identity would have seemed unthinkable just a decade earlier.

Hip-hop hits the mainstream: The Sugarhill Gang's "Rapper's Delight" (1979)

"Now what you hear is not a test, I'm rapping to the beat/And me, the groove and my friends are gonna try to move your feet"
The '70s were tough on cities. Unemployment and recession decimated communities. Crime and pollution were on the rise. That's the picture of inner-city life most Americans saw on the six o'clock news.
On the streets, there was a different story to tell, a story of vitality and joy. That tale got its 14:45 turn on the mic with the release of "Rapper's Delight."
The Sugarhill Gang -- "Wonder Mike" Wright, Henry "Big Bank Hank" Jackson, and Guy "Master Gee" O'Brien -- didn't know each other before recording. They were brought together for a collaboration meant to save the Sugar Hill recording studio from bankruptcy.
The result was hip-hop's first crossover success and the solidification of a cultural phenomenon on vinyl.

The disco queen & the techno scene: Donna Summer's "I Feel Love" (1977)

Donna Summer's proto-techno collaboration with producer Giorgio Moroder is a futuristic vision.
Before the two got together, there was electronic music and there was disco. "I Feel Love" combined the two and created the first disco hit with an entirely synthetic sound.
The song swept the clubs and was dubbed by musician Brian Eno -- a Bowie collaborator and innovator his own right -- as the "the sound of the future."
As Mark Coleman wrote for CNN at the time of Summer's death in 2012, "Perhaps this is the moment when the machines began to take over the music business."
To this day, "I Feel Love" is frequently sampled, and many credit Moroder and Summer as a major influence on techno and electronic dance music.

Folk goes green: Joni Mitchell's 'Big Yellow Taxi' (1970)

"They paved paradise and put up a parking lot"
Environmental catastrophes of the '60s brought a new awareness to the issue in the '70s.
The decade opened with the first annual Earth Day and saw the creation of the EPA and the beginning of the modern environmental movement.
Joni Mitchell's "Big Yellow Taxi" brings a pop sensibility to the issue, comparing lost love to the destruction of paradise after a visit to Hawaii.
The old adage of "you don't know what you've got 'til it's gone" rings with a truth, longing, and a clear warning.
For more on the music of the 1970s, watch "The Seventies: What's Goin' On," August 13 at 9 p.m. ET/PT on CNN.
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