The main biology majors (IB and MCB) are in the College of Letters and Science, which admits frosh as undeclared. However, neither of these is capacity limited, so completing the prerequisite courses with C or higher grades will allow declaring the major.
http://ib.berkeley.edu/undergrad/major/declaring.php
http://mcb.berkeley.edu/undergrad/major/major/declaring
The following are also not capacity limited at UCB:
Earth and planetary science: http://eps.berkeley.edu/undergraduate/declaring-major
Linguistics: https://lx.berkeley.edu/ugrad/apply