Thousands of educators from across Ontario descended on Queen's Park on Saturday to protest impending changes to the province's education system.

The rally was organized by members from five different teachers' unions. Demonstrators, some from as far away as Dryden, Ont., arrived in Toronto in more than 150 buses. They were joined by large groups of parents, students and school board trustees.

"We want to make sure that our voices are heard. We want to make sure students know that we are fighting for them and that we care about them," said Kristen Smyth, who teaches high school drama and ESL in Kitchener, Ont.

The protest comes in the wake of the provincial government's decision to increase average required class sizes in intermediate and high school grades, introduce mandatory e-learning modules and cut at least 3,475 full-time teaching positions, it says through attrition.

School boards have warned the revisions could lead to classes with up to 40 students and result in various electives being cancelled altogether. The fallout could be compounded by an overhaul to Ontario's autism program, which will likely see schools trying to cope with a sudden infusion of students with challenging needs.

On Thursday, tens of thousands of students at some 600 schools across the province staged a walkout to protest the coming changes.

Many at the rally expressed significant concerns about how larger class sizes will ultimately affect students and teachers. (Lorenda Reddekopp/CBC)

No space in classrooms

Marissa White, who teaches art to high school students in Kitchener, says that because many of her courses are electives, she will likely be directly affected by the government's revamps.

"I honestly do not understand how anyone can read about what's happening and think that it's a good idea," she told CBC News from the sprawling lawn at Queen's Park.

"If you're cutting anything to do with education, I don't understand how anyone could think that is going to help our kids."

Wow! What a turn out. This is passion. <a href="https://twitter.com/hashtag/RallyForEducation?src=hash&ref_src=twsrc%5Etfw">#RallyForEducation</a> <a href="https://t.co/lksbSxTQCH">pic.twitter.com/lksbSxTQCH</a> —@mustacs

White said her classes currently have about 33 students. Bigger class sizes will make her daily tasks nearly unmanageable, she says.

"There's not physically enough room. Classrooms weren't built for that many kids. Thinking about how I'm going to do tracking and manage my students, there's no way one person can handle all of that," she continued.

"I can barely fit all my desks in there as it is."

Camryn Bloom, 6, sits on the shoulders of family friend Paul Pellerin at the protest. (Tijana Martin/Canadian Press)

Smyth said that more students and mandated e-learning courses will be particularly difficult for students still learning to speak English.

"I won't be able to have as much time with each student as I would like, to make sure that they are growing, make sure that they are understanding," she says.

"ESL is very focused, it requires one-on-one attention and we want to give that to them."

Fears about out-of-classroom supports

Meanwhile, some fear that schools will lose the capacity to assist students seeking services outside of the classroom.

Ross Newhook, a guidance counsellor at Lorne Park Secondary School in Mississauga, Ont., said "it's very disheartening" that students could see less access to things like mental health support.

"We're seeing such a tremendous increase in mental health issues right now, and that's all going to be downloaded to classroom teachers who — with an increased class size — don't have the capacity to deal with that," he says.

Newhook is up for retirement next year, but said he was compelled to join Saturday's protest because he's concerned about the well-being of Ontario students.

Several protest signs took aim at Education Minister Lisa Thompson's claim that bigger class sizes will make students more 'resilient.' (Lorenda Reddekopp/CBC)

"It's about the students and the quality of education. We talk so much about mental health and program planning, but yet, they won't have the resources to accommodate any of that."

Despite considerable pushback from educators and students, the Progressive Conservative government says it has no intention of revisiting its policy plans ahead of a new round of collective bargaining negotiations this fall.

Minister calls protest 'union tactics'

In a statement Friday, Education Minister Lisa Thompson said the government would not be "distracted by union tactics" such as protests and rallies.

"The fact is that Ontario's teacher unions have been handed control of the education system for the past 15 years," Thompson said.

"Despite what unions say, their priority has not been student success and as a result our province's math scores are dropping and our students find themselves falling further and further behind."

The Ministry of Education says the five-year high school graduation rate was 86.3 per cent in 2017, up from 70 per cent in 2004, and the four-year graduation rate was 79.8 per cent, up from 56 per cent. Math scores for high school students held steady in 2017 compared to 2006, but have declined in elementary school.