Philadephia ? Thanks to the intelligent design movement, Charles Darwin’s birthday is evolving into everything from a badminton party to church sermons this weekend.

Defenders of Darwin’s theory of natural selection are planning hundreds of events around the world Sunday, the 197th anniversary of his birth, saying recent challenges to the teaching of evolution have re-emphasized the need to promote his work.

“The people who believe in evolution … really just sort of need to stand up and be counted,” said Richard Leventhal, director of the University of Pennsylvania’s Museum of Archaeology and Anthropology. “Evolution is the model that drives science. It’s time to recognize that.”

At the University of Victoria in British Columbia, Canada, philosophy students will get a jump-start on Darwin Day on campus today by singing Darwin carols they composed.

Darwin, who was born in England on Feb. 12, 1809, and died in 1882, was 50 when he published “The Origin of Species.”

The intelligent design movement challenges Darwin’s theory, contending that organisms are so complex that they must have been created by some kind of higher being. Critics of intelligent design say it is creationism camouflaged in scientific language.

Intelligent design proponents suffered legal setbacks last year in Pennsylvania and Georgia, but Kansas education officials have approved science standards that treat evolution as a flawed theory.