Biology Form 1 Notes : Introduction To Biology

Introduction to Biology

• Biology is derived from Greek words: BIOS meaning LIFE and LOGOS meaning STUDY or KNOWLEDGE.
• Biology means “life knowledge”.
• It is the scientific study of living things and organisms.

Branches of Biology

• Botany – the study of plants.
• Zoology – the study of animals.
• Microbiology – the study of microscopic organisms.
• Morphology – the study of the external structure of organisms.
• Anatomy – the study of the internal structure of organisms.
• Physiology – the study of the functioning or working of cells and the body.
• Biochemistry – the study of the chemistry of materials in living organisms.
• Cytology – the study of cells.
• Genetics – the study of inheritance.
• Ecology – the study of the relationship between organisms and their environment.
• Taxonomy – the classification and sorting of organisms into groups.
• Histology – the study of the fine structure of tissues.
• Virology – the study of viruses.
• Bacteriology – the study of bacteria.
• Entomology – the study of insects.
• Ichthyology – the study of fish.

Importance of Biology

• It helps us understand the functioning of the human body.
• It explains the developmental changes that occur in living organisms.
• It contributes significantly to improving quality of life.
• It opens up career opportunities in fields such as:
  • Medicine
  • Nutrition
  • Public Health
  • Dentistry
  • Agriculture
  • Environmental Studies
  • Teaching

Characteristics of Living Things

Life is defined through observations of activities carried out by living things:

• Nutrition –
  • Nutrition is the process by which food or nutrients are acquired, made, and utilized by living organisms.
  • Green plants and certain bacteria produce their own food.
  • All other organisms feed on complex organic materials.
• Respiration –
• This is the breakdown of food to release energy.
• The energy released is used for various activities within the organism.
• Gaseous Exchange – The process through which respiratory gases (CO₂ and O₂) are taken in and expelled through a respiratory surface.
• Excretion –
• Excretion is the removal of metabolic wastes from the body.
• Substances such as urea and carbon dioxide (carbon (IV) oxide) are excreted.
• These substances are poisonous if allowed to accumulate in the body.
• Growth and Development –
• Growth refers to an irreversible increase in size.
• All organisms increase in size; that is, they grow.
• Development refers to irreversible changes in complexity.
• As organisms develop, they also become differentiated in form.
• Reproduction – Reproduction is the formation of new individuals of a species to ensure the continued existence of the species and growth of its population.
• Irritability –
  • The ability of organisms to detect and respond to changes in the environment. This ability is crucial for survival.
• Movement –
• Movement is the progressive change in position from one place to another.
• Some organisms are sessile (i.e., fixed to a substratum).
• The majority of plants move only certain parts rather than the whole organism.

Collection and Observation of Organisms

Biology as a practical subject is learned through the humane handling of organisms.

Materials needed for the collection of organisms include:

• Knives to cut portions of plant stems or roots, or to uproot plants.
• Polythene bags to store collected plant specimens.
• Insect collecting jars.
• Insect killing jars.
• Hand gloves for protection.
• Sweep nets for catching insects.
• Pooters for collecting small insects.
• Traps for capturing various organisms.

Observation of Organisms

• Observe the plant or animal in its natural habitat before collecting it.
• Identify the exact location—on the surface, under rocks, on tree trunks, or on branches.
• Determine what the organism feeds on.
• Observe how it interacts with other animals and the environment.
• Count how many individuals of that species are present in a particular area.
• Plant specimens are placed on the bench and sorted into categories such as seeds, stems, roots, leaves, and fruits.
• Animal specimens may be left inside transparent polythene bags.
• Killed specimens are placed in petri dishes.
• Use a hand lens to observe the external features of small animals.

Presenting the Results of Observations

• Organisms are observed carefully and important features are noted, such as color, texture, hardness or softness, presence of hair, and size (measured or estimated).
• Biological Drawings – It is important to draw some of the organisms observed.
  • When making a biological drawing, the magnification (enlargement) should be noted.
  • Indicate how many times the drawing is larger or smaller than the actual specimen using the formula: MG = length of drawing / length of specimen.

How to Draw

• Several drawings of one organism may be necessary to represent all observed features.
• For example, the anterior view of a grasshopper shows all mouth parts clearly but not all limbs.
• The lateral (side) view shows all the legs.

Collection, Observation, and Recording of Organisms

Collection

• Plants and animals are collected from the environment near the school or within the school compound using nets, bottles, and gloves.
• Animals collected include arthropods, earthworms, and small vertebrates such as lizards, chameleons, and rodents.
• Specimens are placed in polythene bags and taken to the laboratory.
• Stinging or poisonous insects are killed using ether.
• Other animals are observed alive and then returned to their natural habitat.
• Plant specimens collected include leaves, flowers, and whole plants.
• Observations are made to show the following:
  • Plants have roots, stems, leaves, and flowers.
  • Animals have legs, hair, hard outer coverings, feathers, eyes, mouths, limbs, and other appendages.

The Differences Between Animals and Plants Collected

Comparison Between Plants and Animals