Admission to the Intercollege Graduate Degree Program in Ecology at Penn State requires the following:

An undergraduate degree in ecology, biology, fisheries, wildlife, forestry, or natural resources, however, applicants with other backgrounds are welcome to apply.
A minimum grade-point average of 3.0 (on a 4.0 scale) during the last two years (junior/senior) of a bachelor's degree at an accredited college or university.
Ideally, you should have taken at least three undergraduate classes in the biological sciences (e.g., biology, ecology, physiology) as well as a minimum of five undergraduate courses in the physical sciences and mathematics with at least one course each in chemistry, physics, calculus.
However, a limited number of course deficiencies in these subjects may be remedied by taking undergraduate courses while a graduate student. Deficiencies must be made up in the first few semesters after admission.
Three letters of recommendation
Personal statement of motivations and goals
Curriculum vitae/resume
Transcript(s)
International applicants must take and submit scores for the TOEFL (Test of English as a Foreign Language) or the IELTS (International English Language Testing System), with the exceptions noted below. The minimum acceptable score for the TOEFL is 550 for the paper-based test, 213 for the computer-based test, or a total score of 80 with a 19 on the speaking section for the Internet-based test (iBT). Applicants with iBT speaking scores between 15 and 18 may be considered for provisaaional admission, enrollment, and, if necessary, remedial course work. The minimum composite score for the IELTS is 6.5. Revised TOEFL PBT July 2017 and later 60