Introduction to Biology
Senior 1 · Biology
Introduction to Biology
Lesson 1 of 4
20 min
Picture four people at work on the same morning. A ranger in Volcanoes National Park records which mountain gorillas in a family are feeding and which are resting. A farmer in Nyabihu turns over the leaves of her Irish potatoes, looking for the brown spots of blight. A laboratory technician at a health centre looks at a drop of blood for malaria parasites. A veterinary officer vaccinates a cow against a disease.
The four jobs look different, but each person is studying a living thing: how it is built, how it works, what harms it, or how it lives with other organisms. That shared subject is biology.
Definition
Biology is the scientific study of living things: their structure, how they work, how they grow and reproduce, and how they interact with each other and with their surroundings.
The word comes from two Greek words: bios (life) and logos (study). Example: finding out how a bean plant takes in water is biology.
Definition
Organism: any single living thing, such as a bacterium, a mushroom, a eucalyptus tree, a mosquito or a person.
Biology is a science, so its knowledge comes from evidence. A biologist:
You will use these steps in every practical in this course.
Life is too large a subject for one person to study all of it, so biology is divided into branches. Many branch names end in -logy (study of), and the first part of the word tells you what is studied.
Figure 1: Eight main branches of biology. Each branch studies one part of life in depth.
| Branch | What it studies | Where you meet it in Rwanda |
|---|---|---|
| Botany | Plants | RAB scientists breed climbing bean varieties that give more beans per hectare. |
| Zoology | Animals | Researchers at Karisoke, founded by Dian Fossey in 1967, study mountain gorilla behaviour. |
| Microbiology | Microorganisms: bacteria, viruses, microscopic fungi and protoctists | Health centres test blood for the malaria parasite; dairies use bacteria to make ikivuguto (fermented milk). |
| Ecology | How organisms interact with each other and with their environment | Restoring the Nyandungu wetland in Kigali so that birds, fish and plants return. |
| Genetics | How characteristics are passed from parents to offspring (inheritance) | Crossing local cattle with dairy breeds to get calves that give more milk. |
| Anatomy | The structure of the body and its parts | Medical students at the University of Rwanda learn where each bone and organ lies. |
| Physiology | How the parts of the body work | A doctor checks how well a patient's kidneys filter blood. |
| Taxonomy | Naming and classifying organisms | Botanists give scientific names to plants collected in Nyungwe forest. |
| Entomology | Insects | Tracking which mosquitoes carry malaria so that spraying is targeted. |
| Biotechnology | Using organisms or their cells to make useful products | Growing disease-free banana plantlets from tiny pieces of tissue in a laboratory. |
Warning
Anatomy or physiology? Students often mix these up. Anatomy answers "what is it and where is it?" (the heart has four chambers). Physiology answers "how does it work?" (the heart contracts to push blood round the body). If the sentence is about structure, it is anatomy; if it is about function, it is physiology.
Worked example 1: which branches are involved?
A scientist at RAB investigates why cassava leaves in the Eastern Province show yellow patches, and finds that a virus spread by whiteflies is the cause. Which branches of biology is she using?
Answer: botany, microbiology and entomology. Real problems usually need more than one branch.
Worked example 2: decoding a branch name
Without looking it up, work out what mycology studies, given that the Greek word mykes means "fungus".
Answer: mycology is the study of fungi, such as the oyster mushrooms grown by many cooperatives in Rwanda.
What are the Branches of Biology? (Free Animated Education). Watch for the branch names that end in -logy and write down what each one studies.
Tip
Memory hook: most branch names are "thing studied + -logy": zoo (animal), eco (house, surroundings), micro (small), entomo (insect). If you know the root, you know the branch.
Practice: biology and its branches
Key points
Sources and credits
Figure 1, the table of Rwandan examples, the worked examples and the practice questions are written by Ganzaa.
