Ecology and Evolutionary Biology

Ecology seeks to understand the processes that control the abundance and distribution of organisms and how they interact with one another in a changing environment. Evolutionary biology provides a unifying conceptual framework for all of biology, including the characteristics of organisms and biological diversity. Taken together, ecology and evolutionary biology form a fundamental, broad, diverse, and interdisciplinary area of scientific inquiry. Study in both areas is necessary for understanding the complex biological issues of today, including fighting diseases, understanding of the responses of life and humankind to Earth’s changing environment, and learning how species develop, thrive, and decline. Also, ecology and evolutionary biology are working toward solving some of the world’s most demanding problems, including sustainability and the future of life on earth, human health and welfare, and wise stewardship of our planet. Students majoring in Ecology and Evolutionary Biology (EBIO) apply scientific approaches to issues in ecology and evolution, with an emphasis on critical evaluation of the literature, generating and testing hypotheses, designing and carrying out experiments to test predictions, and articulating, in oral or written form, the results of investigations.

In light of the broad importance of ecology and evolution for fundamental understanding of living systems, the undergraduate EBIO degree emphasizes knowledge and problem-solving in areas of: 

  • the ecology of organisms, populations, and communities
  • the distribution and function of terrestrial, freshwater, and marine ecosystems
  • principles and patterns of evolution, including natural selection and the history of life on Earth
  • comparative, systematic, evolutionary, and environmental aspects of botany, microbiology, and zoology
  • adaptation of organisms to the physical and biotic environment
  • animal behavior and emotion
  • molecular evolution and population genetics
  • developmental biology and the evolution of development
  • conservation biology and management of ecosystems
  • the relevance of mathematics, chemistry, and physics to biology
  • the development of biological thought
  • infectious disease ecology
  • landscape and ecosytem ecology
  • sustainabilty and human-nature systems
  • energy and biofuels
  • Darwinian medicine
  • health and population genetics
  • genetically engineered organisms

EBIO majors include students who:

  • have strong and compelling interests in the natural world and who are interested in making a difference
  • are interested in pursuing advanced graduate degrees in science, especially biology
  • want careers in the areas of natural resources management, environmental consulting, environmental law, environmental science, science teaching and scientific journalism, among other professions
  • are passionate about making a difference in the lives of others by improving their physical and mental health
  • are interested in many different areas of biology, from the molecular to ecosystem levels

  • are fascinated with the complexity and diversity of nature

A bachelor of arts (BA) degree in EBIO provides excellent training, education, and experience, preparing students for many successful careers and for admission to and success in graduate study or medical school and other health professions:

  • because ecology and evolution are subjects of central importance for understanding the ways all organisms live, grow and survive—everything from microbes to humans

  • because the department and its classes provide students a broad learning experience in the biological sciences
  • because the department’s faculty provide EBIO majors with excellent classes and research opportunities

Course code for this program is EBIO. 

Bachelor's Degree Program(s)

Bachelor’s Degree in Ecology and Evolutionary Biology

Students in EBIO gain a well-rounded education in the sciences and mathematics, with an emphasis in ecology and evolutionary biology. In addition to the general College of Arts and Sciences requirements, students in EBIO must complete 15 credits selected from chemistry, physics, and mathematics, plus a statistics course and 38 hours of course work in EBIO. Up to 12 credit hours of courses taken in other departments may be counted toward the 38 credit hours required for the EBIO major. A list of acceptable courses can be obtained from the EBIO advisor. All required courses must be completed with a grade of C- or better. Students with scores of 4 or 5 on the AP biology test receive 8 hours of credit and are exempt from the general biology sequence (EBIO 1210 and 1220 General Biology 1 and 2, and EBIO 1230 and 1240 General Biology Lab 1 and 2). Students who score in the 66th percentile or higher on the CLEP test in biology receive 6 hours of credit and are exempt from EBIO 1210 and EBIO 1220. EBIO majors with transfer credit in biology from other institutions or advanced placement credits must consult with the EBIO undergraduate advisor. Transfer students must complete at least 12 upper-division (3000-level or above) EBIO courses on the Boulder campus.

Required Courses and Semester Credit Hours   

  • Biology sequence (EBIO 1210 and 1220 General Biology 1 and 2, and EBIO 1230 and 1240 General Biology Lab 1 and 2)—8  
  • EBIO 2040 Principles of Ecology—4  
  • EBIO 2070 Genetics: Molecules to Populations—4  
  • EBIO 3080 Evolutionary Biology—4  
  • One EBIO laboratory or field course, 3000 level or above. Possible choices include:
    EBIO 3170/3175 Arctic and Alpine Ecology
    EBIO 3240 Animal Behavior
    EBIO 3400 Microbiology
    EBIO 3630 Parasitology
    EBIO 3770 Animal Diversity: Vertebrates
    EBIO 3850 Animal Diversity: Invertebrates
    EBIO 4100 Mountain Research Station
    EBIO 4500 Plant Biodiversity and Evolution
    EBIO 4510 Plant Anatomy and Development
    EBIO 4520 Plant Systematics
    EBIO 4660 Insect Biology
    EBIO 4750 Ornithology
    EBIO 4760 Mammalogy
  • EBIO 4000-level or above (at least 6 credits).* Possible choices include:
    EBIO 4030 Limnology
    EBIO 4060 Landscape Ecology
    EBIO 4140 Plant Ecology
    EBIO 4100, 4110, or 4120 Advanced Ecology
    EBIO 4160 Introduction to Biogeochemistry
    EBIO 4175 Ecosystem Management of Public Lands
    EBIO 4180 Ecological Perspectives on Global Change
    EBIO 4290 Molecular Systematics and Evolution
    EBIO 4350 Biological Field Studies
    EBIO 4410 Biometry
    EBIO 4630 Field Techniques
    EBIO 4740 Biology of Amphibians and Reptiles
    EBIO 4800 Critical Thinking
    EBIO 4840, 4870 Independent Study/Research  
  • EBIO electives to bring total in major to 38
    Statistics: MATH 2510, MATH 2520, IPHY 2800, PSYC 3101, or EBIO 4410 (of these, only EBIO 4410 counts toward the 38 hours of EBIO credit required for the major.)

* These 6 hours must be taken in the EBIO department on the Boulder campus, which includes the Mountain Research Station and CU-approved study abroad programs. This can include critical thinking courses, and may include a maximum of 3 hours of independent study or independent research. 

Ancillary Course Work

Choose three classes from the following:

  • *CHEM 1113/1114 General Chemistry 1 and Lab—5
  • *CHEM 1133/1134 General Chemistry 2 and Lab—5
  • PHYS 1110 General Physics 1 (calculus-based)—4 
  • PHYS 2010 General Physics 1 (algebra-based)—5
  • *PHYS 1120/1140 General Physics 2  and Lab (calculus-based)—5 
  • PHYS 2020 General Physics 2 (algebra-based)—5
  • MATH 1300 Analytical Geometry and Calculus 1 (5 hours), MATH 1310 Calculus, Statistics, and Modeling (5 hours) or APPM 1350 Calculus 1 for Engineers (4 hours)
  • MATH 2300 Mathematics for the Environment (5 hours) or APPM 1360 Calculus 2 for Engineers (4 hours)

* Students must take the lecture and lab for these courses

Minor Program

A minor is offered in ecology and evolutionary biology. Declaration of a minor is open to any student enrolled at CU-Boulder, regardless of college or school.

  • A total of 20 credit hours in EBIO with grades of C- or better.
  • A 2.00 GPA or higher for all course work attempted in EBIO.
  • 9 hours of upper-division credits in EBIO.
  • 6 hours of 4000-level credits in EBIO.
  • A minimum of 12 credit hours must be taken on the Boulder campus, including a minimum of 6 of the 9 upper-division credits. Mountain Research Station is considered the Boulder campus.
  • All courses must have an EBIO prefix.
  • EBIO 1030, 1040, 1050, 1300, 3010, 3940, and all independent study and independent research do not count toward the minor requirements.

Required Courses and Semester Credit Hours

  • EBIO 1210 General Biology 1—3
  • EBIO 1220 General Biology 2—3
  • EBIO 1230 General Biology Lab 1—1 
  • EBIO 1240 General Biology Lab 2—1
  • Complete 3 credit hours of lower- or upper-division EBIO courses—3 
  • Complete 3 credit hours of 3000-or 4000-level EBIO courses—3 
  • Complete 6 credit hours of 4000-level EBIO courses—6 
    Minimum total hours for the minor—20 

Concurrent Bachelor's/Master's Program

BA/MA in Ecology and Evolutionary Biology

A combined bachelor’s (BA) and master’s (MA) degree with thesis is offered for highly motivated undergraduate students. The BA/MA program allows students to take advanced courses at an accelerated pace, engage in an independent research project, and obtain both degrees in five years. In addition to preparing graduates for additional graduate study or medical school, the program is expected to position them for employment in areas such as environmental consulting, teaching at the high school or community college level, or by businesses with an environmental or biomedical emphasis. Applications from sophomores and juniors for the BA/MA degree are considered on a competitive basis. Applicants must have an overall GPA of 3.00 or higher in the EBIO major and the support of a faculty research advisor. Applications are available from the EBIO graduate coordinator, and are due on October 15 and March 15.

Candidates for this degree must complete all college core requirements by the end of the senior year. To be awarded both BA and MA degrees, a student must maintain a GPA of 3.00 or better and complete at least 144 credit hours. The BA/MA program requires 24 hours of graduate credit at the 5000-level or above and 4–6 hours of thesis credit. In addition to writing a thesis based on original research, students are examined by their thesis committee in the fifth year on general knowledge in ecology and/or evolutionary biology. The final examination consists of a defense of the thesis before the committee; it should be scheduled by the end of the fifth year.

Students interested in this program are encouraged to consult with the  EBIO associate chair for graduate studies early in their undergraduate career. No financial support is available from the department for students enrolled in this program.

Graduate Degree Program(s)

Graduate Study in Ecology and Evolutionary Biology

The EBIO department offers programs leading to the master of arts (MA) and doctor of philosophy (PhD) degrees in a wide variety of biological disciplines ranging from biogeochemistry to community ecology to evolutionary genetics and others (see description of the undergraduate program above). Modern laboratory facilities for graduate study are located in the Ramaley building. In addition, the department has strong ties with the University Museum, the Institute of Arctic and Alpine Research (INSTAAR), the Institute of Behavioral Genetics (IBG), the Cooperative Institute for Research in Environmental Sciences (CIRES), the Environmental Studies Program (ENVS), and the Departments of Integrative Physiology, Geology, Geography, Anthropology, and Molecular, Cellular, and Developmental Biology. INSTAAR operates the Mountain Research Station, an alpine field laboratory 25 miles from campus. Graduate student support is available in the form of fellowships, part-time instructorships, teaching assistantships, research assistantships, and research grants.

Admission information is provided on the EBIO website ( Foreign applications are due by December 1 and U.S. domestic applications by December 31 for consideration for admission during the subsequent academic year. A completed domestic application includes a statement of intent, three letters of recommendation, official transcripts, and scores on the GRE General Test. Applicants are encouraged to communicate with potential faculty sponsors well before the application deadline. Applications for spring semester admission are not accepted. Students are required to have a bachelor’s degree in biology or an equivalent.

MA I Program

The EBIO MA I program (with thesis) is intended to be a two year course of study that prepares students for admission to PhD programs, teaching positions, or a variety of forms of employment as professional biologists. MA I students’ studies are focused on a research project culminating in a thesis. Prospective students are urged to consult with faculty advisors to determine whether application for the MA I or PhD program is more appropriate. Applications for the MA I program are considered on a competitive basis; the department only admits students for whom financial support is available. Thirty hours of course work are required for the degree, at least 24 of which must be at the 5000 level or above, including 4–6 hours of thesis credit. The thesis topic is presented to the thesis committee as a written research proposal in the second semester of the program, and the committee administers in the third semester an examination on general knowledge in ecology and/or evolutionary biology. The final examination consists of the thesis defense, which should be scheduled during the second year for full-time students.

MA II Program

A non-thesis master’s degree is offered through the EBIO department’s MA II program for students interested in furthering their knowledge of ecology and/or evolutionary biology but not in graduate training beyond the MA. This program is suitable for secondary school teachers and others whose career choices do not require a research thesis. Applicants are required to attain sponsorship from a faculty member prior to submitting application materials. Applicants are considered on a competitive basis; financial support is not guaranteed for MA II students. Thirty credit hours of course work are required for the degree, at least 24 of which must be at the 5000 level or above, including 4 hours of independent research leading to a paper to be presented to the faculty sponsor. An examination on general knowledge in ecology and/or evolutionary biology is administered by the advisory committee in the third semester, and this committee may also require a final oral examination.

PhD Program

The PhD is a research degree, involving the production of a major piece of original research (the dissertation). The program is intended to be a five year course of study that produces graduates who subsequently teach and conduct research at colleges or universities or hold research or leadership positions at other private or government institutions. Applicants are encouraged to communicate directly with potential advisors before applying. Applications are considered on a competitive basis and academic year stipends (teaching or research assistantships) are provided to students in good standing. Students are expected to form a dissertation committee of five faculty members (including one from outside EBIO) after beginning their studies. This committee aids the student in designing a research program and choosing relevant coursework. In addition to the final examination upon completion of the dissertation, the dissertation committee administers an examination (typically in the third semester) on general knowledge in ecology and/or evolutionary biology and a comprehensive examination (typically in the fifth semester) on a written research proposal submitted by the student.

A total of 30 hours of course work must be taken, although independent study credit may be included in this total. A total of 30 hours of dissertation credits must also be taken. PhD students are required to teach for at least one academic year, typically as a teaching assistant for one of the many laboratory courses offered by the department.