The California Gold Rush set the stage for the founding of the institution.
"There were a lot of entrepreneurs, privateers, scientists, teachers, physicians that came out," Academy senior scientist John McCosker said. "And there was a gathering of a number of them, decided the west was so unique. Every plant and animal they saw here was new to them."
They began weekly meetings; members wrote descriptions of new species of plants and animals that were published in the newspaper. Eventually, they built a museum on Market Street and started collecting specimens. One of the prize possessions was a reconstructed mastodon.
"The real tusks of that mastodon were on display and they were enormous," McCosker said. "Of course, the mastodon burned to the ground in 1906 after the earthquake."
In fact, the entire museum was destroyed by the earthquake and fire.
But the mastodon tusks survived, and have been on display ever since.
It took about 10 years for the Academy to open a new museum in Golden Gate Park. A few years later, Steinhart Aquarium was added, with its famous alligator swamp. As years went by, more and more new wings were tacked on.
"There were nine separate building campaigns all by different architects," McCosker said. "And there was really no organization; it was sort of the Winchester Mystery House of museums."
McCosker was director of Steinhart Aquarium for 22 years, and he has been part of the Academy for 35. For years, he was on the forefront of the campaign to repair or replace the ageing museum because of earthquake danger and other problems.
"Nobody thought the aquarium would last this long when they built it," McCosker said. "This is the oldest still operating aquarium in America - 1923 they built this and you can see the old rebar from 1923. All of that saturated sea water just into the concrete and the rebar is disappearing."
Eventually the Board of Trustees decided to replace the entire complex. City bond measures provided $123 million. About $30 million is from the state and federal government. The rest of the $488 million cost is being privately raised.
In 2004, visitors got a last chance to say goodbye to the old exhibits before the animals and exhibits were moved out and one by one the buildings were torn down.
For McCosker, it was a bittersweet moment
"It'll be so very different, it'll be nothing like this," he said. "I hope it's as wonderful and even more exciting. But I'm sad, because this is my life."
It was a tough moment, but now, with the fabulous new building, McCosker and everyone else connected to the Academy is thrilled.
Written and produced by Jennifer Olney