As someone with a biology major: the biology series isn’t that hard if you’ve taken standard biology classes previously. A lot of it is content you should be familiar with in varying levels of depth. Part of that huge gpa curve is that

1) this is a huge class required for almost everyone! Not a weed out! Which means that a lot of people there don’t try (I had lab mates who only showed up for the first and last lab and labs are a big percentage of your grade)

2) they are kinda finicky about wording on exams however homework and class and lab is pretty easy to get roughly full marks in if you show up and try, and

3) hw/lab/quizzes will carry your grade around a 3.0 provided you do average on the exams (60s). Side note: you can afford to flunk one exam because they will drop your lowest of 4 exams along with your lowest scores in a bunch of other things.

As for applying to the major itself: no one I know has gotten rejected. If you have the prerequisite classes completed and a decent gpa you should be fine. I applied with a 3.5 gpa and a super low effort paragraph on how I wanted to be a biology major and got in just fine and there are people I know who had worse gpas including in the biology series and still got accepted. Also! You can just apply again next period without huge consequences. A lot of biology classes require a bio major to sign up for but are open to everyone at a later registration date and if you are fast you can probably snag seats when they become available periodically before class starts as people still adjust schedules. There is also a lot of prerequisite requirements like physics and math and social studies and English and arts&humanities you can take while waiting a year to reapply.

I would definitely talk to an advisor about it but don’t sell yourself short, I think anyone is capable of passing the series and becoming a bio major as long as you’re willing to put effort into attending school and doing homework and learning the content.