Biology: The study of life.

Botany: The study of plants.

Ecology: The study of the relationships between organisms and their environment.

Geology: The study of the Earth's physical structure and history.

Meteorology: The study of the atmosphere and weather.

Physiology: The study of the functions of living organisms.

Psychology: The study of the mind and behavior.

Sociology: The study of human society.

Zoology: The study of animals.

Other -ologies:

* Astrology: The study of celestial objects and their supposed influence on human affairs.

* Cryptography: The practice and study of techniques for secure communication.

* Ethnology: The study of the origin and development of peoples.

* Mycology: The study of fungi.

* Oncology: The study of cancer.

* Pathology: The study of diseases.

* Taxonomy: The science of classification.

* Technology: The application of scientific knowledge for practical purposes.

* Theology: The study of religion and God.

This is not an exhaustive list, but it gives you a good starting point. There are many other "-ologies" out there, depending on the specific field of study.