♪ The Earth BEGAN to cool
The Big Bang Theory Season 7, Episode 23
♪ The Earth BEGAN to cool
The Big Bang Theory Season 7, Episode 20
♪ The autotrophs BEGAN to drool,
Neanderthals developed tools ♪
The Big Bang Theory Season 5, Episode 4
♪ The Earth BEGAN to cool
The Big Bang Theory Season 5, Episode 19
♪ The autotrophs BEGAN to drool,
Neanderthals developed tools ♪
The Big Bang Theory Season 12, Episode 14