Key Concept:
Some key discoveries in biology—such as the cell theory, germ theory, and DNA structure—have transformed our understanding of life and opened doors to scientific and medical breakthroughs.
Short Notes:
Biology is a growing science shaped by many revolutionary discoveries that changed how we understand living things. One of the earliest and most important discoveries was the cell theory, which states that all living things are made of cells and that the cell is the basic unit of life. This discovery laid the foundation for modern biology and was made possible by the invention and improvement of the microscope.
Another major breakthrough was the germ theory of disease, developed by scientists like Louis Pasteur and Robert Koch. This theory showed that diseases are caused by microorganisms, leading to advances in hygiene, vaccines, and public health. It completely changed how people prevent and treat infections.
One of the most important discoveries in modern biology is the structure of DNA, described by James Watson and Francis Crick in 1953. They found that DNA is a double helix and carries the genetic instructions for all living things. This discovery led to the development of genetic engineering, biotechnology, and fields like genomics and bioinformatics.
Other discoveries include Mendel’s laws of inheritance, which explain how traits are passed from parents to offspring, and the development of vaccination and antibiotics, which have saved millions of lives. Each of these discoveries brought new knowledge and tools that help biologists improve human health, agriculture, and environmental protection.
Key Terms:
- Cell theory – All living things are made of cells,
- Germ theory – Diseases are caused by microorganisms,
- DNA – Molecule that carries genetic information,
- Microscope – Instrument that magnifies small objects,
- Genetics – Study of heredity and variation,
- Inheritance – Passing of traits from parents to offspring,
- Vaccine – A substance that provides immunity to disease,
- Antibiotics – Medicines that kill or stop the growth of bacteria,
- Genetic engineering – Direct manipulation of DNA,
- Biotechnology – Use of living systems in technology and industry,
- Bioinformatics – Use of computers to analyze biological data,
- Double helix – Structure of the DNA molecule.
Example:
In Ethiopia, modern biological discoveries like the development of the BCG vaccine (against tuberculosis) have had a strong impact on public health, helping reduce the spread of serious diseases.
ESSLCE Practics Zone
Click here
Exam Link: This topic appeared in the Ethiopian National Exam, Year 2016.
Sample ESSLCE Question:
Which of the following discoveries led to the understanding that diseases are caused by microorganisms?A. Mendelian inheritance
B. Germ theory
C. Cell theory
D. Natural selection
Correct Answer:
B. Germ theory
Explanation:
The germ theory explained that microorganisms, not bad air or spirits, cause diseases—revolutionizing medicine.
Next Topic Preview:
Next, you’ll explore how these biological discoveries have influenced society and the environment—helping improve agriculture, health, and our understanding of nature.
Responses