You are admitted into a “proposed major” at UCSC. Transfer students who have met the major qualification requirements are encouraged to declare the major immediately upon arrival. Students who are proposed in a different major and have advanced standing when they come to UC Santa Cruz require permission from the department to change into the major. Admission to the major is not guaranteed.
To declare the Biological Sciences major as transfer, you need to meet these transfer requirements: https://mcd.ucsc.edu/academics/undergraduate/transfer-students/transfer-admission.html