Various job roles one can get after graduating as biologists are:-

Research- Research biologists study the natural world using the latest scientific tools and techniques in both laboratory setting and outdoors to understand how living systems work.

Health Care- Biologists may develop public health campaigns to defeat illnesses such as TB, AIDS, cancer and cardiovascular diseases. Some may work to prevent the spread of rare and deadly diseases. Veterinarians attend to sick and injured animals and doctors and other allied health care professionals maintain the general health and well being of their patients.

Environmental Management and Conservation- Biologists in-management and conservation careers work on solving environmental problems and preserving the natural world for future generations. Park rangers protect state and national parks,assist in preserving their natural resources and educate the general public. Zoo biologists carry out endangered species recovery programs

Biotechnology- Biologists work in the area of biotechnology develop and enhance products, tools and technological advances in fields such as agriculture, food science and medicine.

Forensic science- forensic biologists work with large enforcement agencies using scientific methods to discover and process evidence that can be used to solve crimes.

Science writing and communication- Journalists and writers with science background write and publish science journals to inform the general public about relevant and emerging biological issues.

Bioinformatics- Biologists in fields such as bioinformatics and computational biology apply mathematical techniques to solve biological problems such as modelling ecosystem processes and gene sequencing.

Politics and policy- Science advisers work with lawmakers to create new legislation on topics such as bio medical research and environmental protection.

Colleges and universities- Those with teaching aptitude may take up job as professor or lecture of advanced biology courses.

Business and industry- Biologists work wit drug companies and providers of scientific products and services to research and test new products. They also make take up sales, marketing and public relations positions.

One can take up the role of ecologists, geneticist, botanist, zoologist, bio technologist, biochemist, forest ranger, farming consultant , biology content developer, horticulturist etc after graduating as biologist

Dear aspirant, after graduating as biologist there are lot of scopes. Let me clrify it more about graduate. IN Indian scenario graduate means, a person who has obtained a degree of Bachelor. But in western hemisphere, a graduate means a higher degree, it could be Masters.
In Indian context, mere graduation will fetch you jobs but not that much. After graduation as biologist, I beleive that Indian universities are not offering a apecial course in Biology, it could be Zoology, Botany, Microbiology, Biotechnology, Biochemistry, Genetics along with chemistry and many more combinations.
IN my opinion you should opt a master degree course in any biological subject. It all depends upon your interest, in which field you want to pursue your studies. Again if you opt for Microbiology then you can choose Medical, clinical, industrial, pharmaceutical, food, agricultural, molecular or general microbiology.
If you opt for Biotechnology stream then again there are lot of opportunities. In nutshell my opinion is that you have to study further to become a Biologist.

ANother interesting subjects are higher degree in Botany or Zoology. By studying these sbjects you can call yourself Botanist or Zoologist, which are a sort of Biologist. To become a professional Biologist better go for higher degree of PhD.
My concern is tell you about the various degree courses, by opting any one of that you can achieve waht you want. Lets take an example of burning field of today, that is Biotechnology. Any one who is working on welfare of human being by using living organisms or living cells is called as Biotechnologist. You may choose working on or studying the biological aspects of humans, animals, plants or microorganisms.
By choosing any of the subject mentioned above you may call your self as Biotechnologist, Microbiologist. Biochemist, Genetecist, Physiologist or in a broad way a Biologist.
Aa a Biologist you can channelize your interest and energy into a educationist or researcher or scientist. BY being educationist, you will be able to teach the students what you have learned. By being researcher or scientist you will have the freedom to explore more and more. Then sky will be the limt to quench the thirst of your ideas.
It does not mean that by opting Botany, you can only study the plant kingdom or by opting zoology, your area of work will be limited to animals only. No...you even can diversify your subject and you even can work on microorganisms, or in any field.