Basic Concepts and Terminologies of Biology

Life is the condition that distinguishes living organisms from non-living matter. All living things share certain characteristics that define life.

The basic unit of life is the cell. All living organisms are made up of cells. Cells are very small and cannot be seen with the naked eye. They can only be observed using a microscope.

Biology has two main branches:

1. Botany – the study of plants
2. Zoology – the study of animals

There are also several minor branches of biology that focus on specific areas of living things. These include:

1. Nutrition Nutrition is the process through which living organisms obtain and use materials from their surroundings. Certain organisms, such as green plants, blue-green algae, and some protoctists, produce their own food through photosynthesis. This process uses sunlight, water, and carbon dioxide to create energy-rich food substances.

   

   Plant

2. Respiration The food that organisms consume contains energy, but this energy needs to be released through a process called respiration. During respiration, food is broken down inside the cells to produce energy that the organism can use. This energy supports functions such as movement, growth, and other life activities.

   

   Lion eating meat

3. Excretion As living things carry out life processes like nutrition and respiration, they produce waste materials. Some of these wastes are harmful if they remain inside the body. Excretion is the process by which organisms get rid of these unwanted substances, also known as metabolic wastes. Examples include urea, extra water, and carbon dioxide. Urea and excess water are mainly removed through urine and sweat. Carbon dioxide and water vapor are expelled through breathing.

4. Growth and Development Growth is an increase in size and weight due to the multiplication and enlargement of cells. Development, on the other hand, involves changes that make an organism more complex. This includes the specialization of cells to carry out specific functions. As a result, the organism changes in form and becomes more efficient in its functions.

   

   Growth and development (a) bean seed to a plant and (b) an egg to a chicken

5. Sensitivity or Irritability All living things can detect and respond to changes in their environment. This ability is called sensitivity or irritability. The things that cause these changes are known as stimuli (singular: stimulus). For example, humans respond to pain, heat, or cold, while a snail pulls into its shell when touched. Plants also respond to stimuli, although their responses may be slower or less visible. A clear example is the mimosa plant, which folds its leaves when touched.

   

   Sensitivity or irritability

6. Movement Living organisms have the ability to move by themselves. Unlike non-living things, which only move when acted upon by an external force, living things move as a natural part of life. Animals move from place to place to find food, water, mates, or a safer environment. This kind of movement is called locomotion. Plants do not move from one location to another, but they do show movement through growth. For example, plant roots grow towards water, and shoots grow towards light.

   

   Cheetah running

7. Reproduction Reproduction is the process by which living things produce new individuals of the same kind. This ensures the survival and continuation of a species. For instance, people give birth to babies, chicks hatch from chicken eggs, and maize seeds grow into maize plants. Non-living things cannot reproduce.

   

   Chick hatching from an egg

1. It helps people understand how their bodies function.
2. It enables people to conserve the environment and use natural resources wisely.
3. It helps us to evaluate environmental issues such as pollution, global warming, and environmental degradation.
4. It helps us understand the causes, symptoms, methods of transmission, prevention, and treatment of diseases.
5. It provides answers to basic questions about life and living organisms.
6. It prepares learners for careers in medicine, agriculture, genetic engineering, pharmacy, environmental science, and veterinary science.
7. It increases our appreciation of nature and the importance of biodiversity.

Biology is not an isolated field of study. It is closely related to many other scientific disciplines such as Agriculture, Medicine, Pharmacy, Veterinary Medicine, and Nutrition. These fields all involve research on living organisms, and discoveries in Biology play a crucial role in advancing them.

a. Agriculture

Agriculture involves the cultivation of crops and the rearing of animals for food, income, or both. Biological research has significantly enhanced agricultural productivity.

• Scientists have developed high-yield and fast-maturing breeds of crops and livestock.
• For example, while indigenous breeds of chickens begin laying eggs at around eight months, improved breeds known as layers can begin laying as early as five months.
• Improved breeds also include varieties suited to specific climatic conditions, such as disease-resistant maize that can thrive in harsh environments.

Improved layer breed

b. Medicine and Pharmacy

Medicine focuses on the prevention, diagnosis, treatment, and cure of diseases, while Pharmacy deals with the preparation and administration of drugs. Biology provides foundational knowledge in both fields through the study of areas such as Anatomy and Immunology.

• Anatomy helps doctors understand the structure and function of the human body, allowing them to diagnose and treat medical conditions effectively.
• Immunology focuses on how the body defends itself against pathogens. This field contributes to the development of vaccines and drugs, many of which are derived from plants, animals, fungi, or microorganisms.

c. Nutrition

Biology is essential for understanding the composition and nutritional value of various food groups. This knowledge is applied by dieticians to design appropriate diets for people with different health needs.

• Biologists have developed breeds of livestock and crops with enhanced nutritional value.
• Examples include vitamin A-rich sweet potatoes and the Jersey cow, which produces milk with low butterfat content.

Jersey cow

d. Forestry

Forests are vital resources, providing fuel, construction materials, medicinal plants, and serving as water catchments. Biological research has contributed to forest conservation and restoration efforts:

• Development of tree species that thrive in dry areas, used for afforestation (planting trees in previously barren areas).
• Introduction of fast-growing tree species to replace trees lost due to deforestation, a process known as reforestation.

These practices help conserve water sources, restore ecosystems, and prevent desertification.

Deforestation and afforestation