The Academy, home to a rare collection of 17 million specimens, and Drexel, the nation's 14th largest private university, said that their formal affiliation will result in "a nationally-recognized powerhouse for discovery in the natural and environmental sciences."
They said it would take advantage of "the vast intellectual and physical capital of each institution, creating value for them and for Philadelphia."
Gephart unveiled the plan to the Academy staff this morning, and he said that at the end, they applauded.
Legally, the Academy will retain its name, its nonprofit status and its board. But officials said that it would become known as the Academy of Natural Sciences of Drexel University.
As a subsidiary of Drexel, the Academy's $51 million endowment will be managed by Drexel, but continue to be wholly dedicated to the Academy.
The two institutions plan to work together more closely on research into natural and environmental science issues. Officials said that, together, the Academy and Drexel would be better positioned to compete for grants and investments from philanthropists, private foundations and government agencies, such as the National Science Foundation.
At a time when Philadelphia non-profits have had to wrestle with complicated and painful decisions - such as the Barnes Foundation moving its collection to Philadelphia, the orchestra filing for bankruptcy, and the sale of Thomas Eakins' 1875 painting, "The Gross Clinic by Thomas Jefferson University - the affiliation of the Academy and Drexel is seen as bold.
"Others in the nonprofit sector should look to this merger as a model of sound and creative decision making, which will provide for a secure and successful future for these great institutions," said Pew president Rebecca W. Rimel.
Gephart, the first head in recent memory that was a businessman instead of a scientist, said that months ago, Academy leaders "recognized that we needed a partner to help us more fully capitalize on our strengths - including our location on one of the best half city blocks in Philadelphia and a rock-solid balance sheet with a $51 million endowment - and to grow at the rapid pace we desire."
They decided that "collaborating with a science-led, university-based partner would allow us to advance our science and musem more innovatively and comprehensively that we could on our own, and our choice is Drexel."
Drexel president John A. Fry said the two institutions combine 300 years of "contributions to our understanding of the world around us. Today, we build on that history for the benefit of our community and the world."
He said it would move Drexel into "a national leadership position" in environmental science and policy.
The Academy, founded in 1812, an age of classic expeditions and scientific exploration, will celebrate its bicentennial next year.
Today, the Academy's reseachers are engaged in cutting-edge work and lately have been expanding their environmental projects.
Its collection of 17 million plant and animal specimens includes birds collected by John James Audubon, herbs collected on the cross-continuent expedition of Lewis and Clark. It has more crickets, grasshoppers and diatoms - single-celled algae found in bodies of water - than any other museum in the world.
But in recent years, the Academy faced financial woes. The staff was reduced, and in 2009 the institution instituted a five percent salary cut.
At one point officials decided to sell off some of the mineral collection, although the sale was later halted.
Under Gephart's leadership, the Academy's endowment has rebounded from $43.1 million in 2008 to $51 million today.
Officials said the merger would allow the collections to be preserved and enhanced, "and Drexel's ambitious research and educational priorities will be expanded and advanced."
Mayor Nutter said he supported the move. "The idea of two of our prominent organizations in science and education coming together to advance Philadelphia's reputation as a scientific leader is one that I support fully," he said "The advantages are clear, and the city, our citizens, and the natural and environmental sciences communities will be the beneficiaries."
The boards of both organization approved the merger Wednesday, but finalizing the agreement could take 45 to 60 days, officials said.
Contact staff writer Sandy Bauers at 215-854-5147 or firstname.lastname@example.org. Visit her blog at http://go.philly.com/greenspace