A fish pond teeming with biological specimen. Image credit bigrockponds.com

ZIMSEC O Level Biology Notes:Principal Branches of Biology

  • The division and different branches of science are constantly spreading with the increase of knowledge in science.
  • The two main branches of science are Physical science and Biological Science.
  • Physical Science is also called the science of non-living things.
  • In Physical Science characteristics, chemical reactions and many similar other properties of non-living objects are examined and discussed.
  • Observation, examination and study of livings things are included in Biology.
  • Therefore Biology is defined as the study of living things.
  • The term Biology comes from two Greek words
  • bios which means life and
  • logos means knowledge
  • Aristotle is regarded as the father of Biology.
  • There are two types of life in nature.
  • One is plant life while the other is animal life.
  • Accordingly Biology has been divided into two branches: Botany and Zoology.
  • Botany deals with the science of plants.
  • It is the branch of biology that deals with plant life, research about characters and other features of plants.
  • Zoology is in subjects relating to the study of animals.
  • It is the branch of biology that involves the study of animals and animal behavior.
  • Inspite of this main two branches nowadays extensive research has been done on microorganisms and bacteria.
  • A microorganism is an organism that can be seen only with the aid of a microscope and that typically consists of only a single cell.
  • Microorganisms include bacteria, protozoans, certain algae and fungi.
  • They influence human life in various ways.
  • The study of microorganisms is known as Microbiology.
  • Considering the subjects of living bodies on which discussion is made the whole range of Biology is divided into the following main branches.
  • Morphology: This branch deals with both the external and internal structures of organisms.
  • The subject concerning internal structures is also known as Anatomy.
  • Cytology: Each living organism consists of one or more cells. Structures and functions of cells are studied in this branch of Biology, (the study of cells).
  • Histology: This is the study on structure, location and function of different tissues.
  • Physiology: This branch includes all the activities of living things for example growth, respiration, excretion, photosynthesis and other biological activities.
  • Taxonomy: In this branch discussion is made on identification, nomenclature, and classification of plants and animals into groups and subgroups.
  • Genetics: the study of how different characters are inherited from parents to offsprings, and how the processes can be controlled and improved, are brought under study and research in this branch. It can also be defined as the study of heredity and the variation of inherited characteristics.
  • Ecology: This branch considers the effects of the environment on living organisms or living communities and also interaction between them.
  • Evolution: This branch deals with the origin and successive transformations of living organisms.
  • Biotechnology: This is the exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics and hormones.

To access more topics go to the O Level Biology Notes page

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