Biology Notes
Introduction to Biology
Biology derived from Greek words-BIOS meaning LIFE and LOGOS meaning STUDY
or KNOWLEDGE.
Biology means "life knowledge".
It is the study of living things/organisms.
Branches of Biology
Botany - study of plants.
Zoology - study of animals.
Microbiology - study' of microscopic organisms.
Morphology - study of external structure of organisms.
Anatomy - study of internal structure of organisms.
Physiology - study of the functioning or working of the cells or body.
Biochemistry - study of the chemistry of materials in living organisms.
Cytology - study of cells.
Genetics - study of inheritance.
Ecology- study of the relationship between organisms and their environment.
Taxonomy - sorting out of organisms into groups.
Histology - study of fine structure of tissues.
Virology - study of viruses.
Bacteriology - study of bacteria.
Entomology - study of insects.
Ichthyology - study of fish.
Importance of Biology
One learns about the functioning of the human body.
One understands the developmental changes that take place in the body.
It contributes immensely to improved life.
It enables one to enter careers such as:
Medicine,
Nutrition,
Public Health,
Dentistry,
Agriculture
Environmental Studies.
Teaching
Characteristics of Living Things
Life defined through observations of activities carried out by living things;
Nutrition –
Nutrition is the processes by which food/nutrients are acquired/made and utilized
by living organisms.
Green plants and certain bacteria make their own food.
All other organisms feed on complex organic materials.
Respiration –
This is the breakdown of food to provide energy.
The energy released is used for various activities in the organism.
Gaseous Exchange –Process throw which respiratory gases(CO2&O2) are taken in and
out through a respiratory surface.
Excretion –
Excretion is the removal of metabolic wastes from the body.
Substances like urea, carbon dioxide (Carbon (IV) oxide).
These substances are poisonous if allowed to accumulate in the body.
Growth and Development –
Growth means irreversible change in size.
All organisms increase in size that is, they grow.
Development is irreversible change in complexity.
As they do so, they also become differentiated in form.
Reproduction-Reproduction is the formation of new individuals of a species to ensure
continued existence of a species and growth of its population.
Irritability –
The ability of organisms to detect and respond to changes in the environment.
This is of great survival value to the organism.
Movement –
Is the progressive change in position from one place to another.
Some organisms are sessile (i.e. fixed to the substratum).
The majority of plants move only certain parts.
The differences between animals and plants collected.
Comparison Between Plants And Animals
Plants Animal
Plants are fixed in position and do Most animals move in search of food,
l. l.
not" move. shelter and mates.
2. Respond slowly to stimuli. 2. Respond quickly to stimuli.
3. Cells have cellulose cell walls. 3. Cells have no cell walls only a cell
4. Plants make their own food from membrane
4. Animals feed on already made food.
simple
materials such as CO2 and water
using
light energy.
