The UC’s consider all 3 UC GPA’s so using the Rogerhub caculator posted by @lkg4answers, repost with all her UC GPA’s. Undeclared major is not an issue since many majors are found in the College of Letters and Sciences which admit all students as Undeclared. Then the students need to take specific course requirements and maintain a specific GPA to declare the major. Undeclared does not necessarily mean an easier admit.
Biology is highly competitive and impacted at the majority of the UC’s so if the major is housed in the College of Letters and Sciences at any of the UC campuses, it will not make a difference she if lists that major or Undeclared. If Biology is housed in specific college for Biological sciences then it could be a tougher admit.
Biology is found in the College of L&S at the following campuses:
UCB
UCLA (The College)
UCSB
UCSC
Biology is found in Natural Sciences or Biological Sciences College:
UCSD (Capped major=Impacted)
UCD
UCR
UCI
UCM
That said, I will list how each campus admits Freshman:
UCB:
Division (L&S, CNR, CoC, CED, CoE) matters for admission selectivity
Note that L&S admits students as undeclared; admission to capped majors (e.g. CS, economics, psychology, ORMS, statistics, art practice, and a few others) is by college GPA in prerequisite courses (and portfolio for art practice) after attending for a few semesters.
UCB does not consider alternate majors.
UCD:
Admission decisions are made based upon the qualifications of the applicant pool and the number of available spaces within each academic area:
• College of Agricultural and Environmental Sciences admits by college
• College of Biological Sciences admits by college
• College of Letters and Science admits by College but within specific academic departments: ie. (Humanities, Arts and Cultural Studies; Mathematics and Physical Sciences; Social Sciences)
• College of Engineering admits by academic department
Students applying as “undeclared” or “undeclared/exploratory” are considered within the college/academic department to which they applied.
Applicants are encouraged to list an alternate major, but not in the
same area as the primary major (e.g., Computer Science Engineering with alternate Computer Science in the College of L&S). Occasionally, UCD admits to the alternate major.
UCI:
UCI admits into the University first and then into the major. In the case that UCI is unable to accommodate all qualified applicants in their first-choice major, those students who indicate a valid alternate major may be offered admission in that major or Undeclared.
UCLA:
For the College of Letters and Science, the applicant’s major is not considered during the review process. Alternate majors are not considered.
UCSD:
The campus does not admit students on the basis of academic major or choice of UC San Diego undergraduate college. UCSD admits into the University first then into the major. Alternate majors are considered and capped majors are highly competitive. Also note: Capped majors require additional pre-req courses and specific GPA to be able to qualify if changing majors. Also if applying to a capped major, select an non-capped major as an alternate.
UCSB:
College of Letters and Sciences: Choice of major is not considered in selection to the College of Letters and Science. Alternate majors are considered for Engineering applicants if a major in the College of L&S is listed.
UCSC:
Choice of major does not influence the selection of first-year students, except for those applicants interested in a major offered by the Jack Baskin School of Engineering (BSOE).
UCR/UCM:
Admission by major but alternate/2nd choice major will be considered if applicant does not meet their first choice admission standards.