Chapter 1: Life Lesson
Physical Biology
Biology is called "Biology" in English. The word is derived from the Greek words "bios" (life) and "logos" (knowledge).
(e) Embryology: This branch deals with the study of reproductive cells, fertilized zygotes, embryo formation, structure, differentiation, and
development.
(f) Cytology: This branch discusses the structure, function, and division of cells in living organisms.
Theoretical aspects are discussed in the branch of physical biology. Some of the major topics covered include:
(a) Morphology: The study of the overall structural or physical formation of organisms. The external description of the body is called external
morphology, and the internal description is called internal morphology.
(b) Taxonomy: The classification of organisms and the rules of categorization.
(c) Physiology: The study of biochemical processes in different body parts, such as respiration, secretion, photosynthesis, etc.
(d) Histology: The study of the structure, composition, and functions of body tissues.
(g) Genetics: The study of genes and heredity in organisms.
(h) Evolution: The study of the origin and development of organisms over time.
(i) Ecology: The study of the interactions between organisms and their natural environment.
(j) Endocrinology: The study of the functions of hormones in living organisms.
(k) Biogeography: The study of the distribution and adaptation of organisms across different geographical regions of the world.
Applied Biology
There are several applied branches of biology, including:
(a) Paleontology: The study of prehistoric organisms and fossils.
(b) Biostatistics: The study of statistical applications in biological research.
(c) Parasitology: The study of parasitism, the life cycle of parasites, and diseases related to parasites.
(d) Fisheries: The study of fish, fish production, and the management of fisheries resources.
(e) Entomology: The study of insects, their roles, benefits, and harmful effects.
(f) Microbiology: The study of viruses, bacteria, microscopic fungi, and other microorganisms.
(g) Agriculture: The scientific study of farming and crop production.
(h) Genetic Engineering: The study and application of genetic modification and engineering.
(i) Biochemistry: The study of the chemical processes in living organisms.
(j) Environmental Science: The study of environmental issues and their effects on organisms.
(k) Marine Biology: The study of marine life and ecosystems.
(l) Forestry: The study of forests, forest resources, and conservation.
(m) Biotechnology: The study of biological applications for human and environmental welfare.
(n) Pharmacy: The study of medicinal sciences and drug formulation.
(o) Wildlife Science: The study of wild animals and their conservation.
(p) Bioinformatics: The application of computer science in biological research, such as cancer analysis.
Classification of Living Organisms
The classification of living organisms was first divided into two kingdoms: plants and animals. However, in 1969, R. H. Whittaker proposed a
five-kingdom classification based on characteristics such as DNA and RNA composition, cellular properties, and modes of nutrition. This
classification was further refined by Margulis in 1974.
The five kingdoms are:
(1) Monera: This kingdom includes prokaryotic microorganisms, such as bacteria and blue-green algae.
(2) Protista: This kingdom includes eukaryotic, single-celled organisms like Amoeba and Paramecium.
(3) Fungi: These are multicellular or single-celled organisms that absorb nutrients, such as mushrooms and Penicillium.
(4) Plantae: These are photosynthetic organisms with developed tissues, such as trees and flowering plants.
(5) Animalia: This kingdom includes eukaryotic, multicellular animals that ingest food.
Binomial Nomenclature
Scientific names of organisms consist of two parts: the genus name (capitalized) and the species name (lowercase). For example, the scientific
name of the potato is Solanum tuberosum, where Solanum is the genus and tuberosum is the species. This system, known as binomial
nomenclature, was introduced by Carl Linnaeus in 1753.
International codes regulate the naming of organisms:
Plants follow the International Code of Botanical Nomenclature (ICBN).
Animals follow the International Code of Zoological Nomenclature (ICZN).
Some examples of binomial names:
Rice: Oryza sativa
Mango: Mangifera indica
Royal Bengal Tiger: Panthera tigris
Human: Homo sapiens
Importance of Biological Classification
The classification of organisms follows a hierarchical structure:
1. Kingdom
2. Phylum/Division
3. Class
4. Order
5. Family
6. Genus
7. Species
For example, the classification of humans (Homo sapiens) follows this order:
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primate
Family: Hominidae
Genus: Homo
Species: sapiens
This system helps scientists categorize and understand the vast diversity of life on Earth.
