Plans were announced one week ago to close the museum.
RELATED: Philadelphia's Academy of Natural Sciences museum to close after nearly 200 years
The rally was organized by Philadelphia Science Action and Green Philly.
"The Academy is not just a building filled with collections. It's a gathering place for Philadelphia's environmental and scientific community," said Julie Hancher with Green Philly.
RELATED: Philadelphia leaders work to preserve Academy of Natural Sciences as museum prepares to close
This comes as David Cohen, an attorney and former U.S. Ambassador to Canada, is collaborating with the offices of Governor Josh Shapiro and Philadelphia Mayor Cherelle Parker.
He is working to broker a deal between the Academy and Drexel University to preserve the educational and research programs.
The museum is set to close to the public on September 30.