BENTONVILLE — Northwest Arkansas Classical Academy officials expect nearly all of their classrooms to be full even after they increase capacity by more than 20 percent this fall.

The charter school, which opened on Melissa Drive in August for grades kindergarten through eight, received more than 700 applications for the 540 seats that will be available when the 2014-15 school year begins. It will add a ninth grade next school year and plans to add one more grade level each year after that.

Of the school’s current 403 students, 399 chose to re-enroll for next year, said Timm Petersen, the school’s headmaster. Another 325 students submitted applications.

A lottery was held Thursday to determine which of the other students who applied would be admitted. Wait lists also were generated for those students who didn’t make the cut. Michael Crouch, a research associate at the University of Arkansas’ education policy office, conducted the lottery. About 40 people came out for the event, even though attendance was not required to qualify for admission.

Priority was given to siblings of current students at the school. At the kindergarten level, where there will be room for 60 students, 28 of 116 applicants were siblings of current students, Petersen said.

The school has 36 staff members this year. It anticipates adding seven to 10 more staff members next school year while adding a section to its first, second and third grades, Petersen said.

There is a waiting list for grades kindergarten through eight. Some ninth-grade spots are still available.

Northwest Arkansas Classical Academy is run by Responsive Education Solutions, a Texas-based organization formed in 1999 by three longtime Texas educators. It runs several dozen charter schools in Texas and three in Arkansas.

Charter schools are public schools of choice that operate free from many of the regulations applied to traditional public schools, according to the Arkansas Department of Education.

Robert Maranto, the 21st Century chair in leadership in the Department of Education at the University of Arkansas, visited Northwest Arkansas Classical Academy in early December to see how things were going.

“We were really impressed,” Maranto said. “Usually first-year schools have a lot of growing pains. It was much better organized than first-year charter schools usually are. I was pleasantly surprised.”

Responsive Education Solutions came under fire earlier this month when the online magazine Slate published a story accusing the organization’s schools of trying to subvert the theory of evolution by introducing creationism through the texts they use.

Zack Kopplin, the story’s author, cited ways he claimed the schools’ textbooks are politically and religiously biased in discussing not only science but also history and social issues. Kopplin obtained the materials through public-record requests. His story also explores Responsive Education Solutions’ connections to conservative, Christian homeschooling programs.

Chuck Cook, Responsive Education Solutions’ chief executive officer, issued a 1,500-word response to Slate’s story shortly after it published.

“Regarding the assertion that ResponsiveEd improperly ‘allow[s] creationism into public-school classrooms,’ the answer is no,” Cook wrote. “As was explained to Slate last November, ResponsiveEd’s ‘science curriculum teaches evolution, noting, but not exploring, the existence of competing theories.’”

In response to criticism of Responsive Education Solutions’ approach to history, Cook wrote, “While Slate claims that it ‘discovered problems’ with ResponsiveEd’s history course, it does not go so far as to assert that the course violates any standard, regulation or law.”

Petersen said he’s not worried about how Northwest Arkansas Classical Academy handles the teaching of evolution.

“We’re not biased toward anything,” Petersen said. “I can say we are definitely not violating anything the state of Arkansas would allow. Does the question (about creationism) come up in class? Probably. On a lot of those types of questions, our response is, go talk to mom and dad.”

Kimberly Friedman, a spokeswoman for the Arkansas Department of Education, did not return messages left for her Friday.

Joe Quinn, a Northwest Arkansas Classical Academy board member, referred to Cook’s response when asked about the Slate story.

“In Bentonville we really haven’t had anything to do with that,” Quinn wrote in an email.