Form 1 Biology: Introduction To Biology

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 – the study of plants.
  
• Zoology – the study of animals.
  
• Microbiology – the study of microscopic organisms.
  
• Morphology – the study of external structure of organisms.
  
• Anatomy – the study of the internal structure of organisms.
  
• Physiology – the study of the functioning or working of the cells or 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 – sorting out of organisms into groups.
  
• Histology – the study of 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

• 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.
  

Collection and Observation of Organisms

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

Materials needed for collection of organisms:-

• Knives to cut portions of plant stem/root or uproot.
  
• Polythene bags to put the collected plant or specimens.
  
• Insect collecting jars.
  
• Insect killing jars.
  
• Hand gloves.
  
• Sweep nets
  
• Pooters
  
• Traps
  

Observation of Organisms

• Observe the plant/animal in its natural habitat before collecting.
  
• Identify the exact place -on surface, under rock, on tree trunk, on branches.
  
• What does it feed on?
  
• How does it interact with other animals and the environment?
  
• How many of that kind of plant or animal are in a particular place?
  
• Plant specimens placed on the bench and sorted out into;- seeds/stems/roots/leaves/fruits.
  
• Animal specimens may be left inside polythene bags if transparent.
  
• Others (killed ones) are put in petri dishes.
  
• Use hand lens to observe the external features of small animals.
  

Presenting the Results of Observations

• Organisms are observed and important features noted down: colour, texture hard or soft; if hairy or not. Size is measured or estimated.
  
• 
  Biological Drawings – It is necessary to draw some of the organisms.
  
  • In making a biological drawing, magnification (enlargement) is noted.
    
  • Indicate the magnification of your drawing.
    
  • i.e how many times the drawing is larger/smaller than the actual specimen MG=length of drawing/length specimen
    

How to Draw

• Several drawings of one organism may be necessary to represent all features observed, e.g.
  
• Anterior view of grasshopper shows all mouth parts properly, but not all limbs.
  
• Lateral (side) view shows all the legs.
  

Collection, Observation and Recording of Organisms

Collection

• Plants and animals collected from the environment, near school or within school compound using nets, bottles and gloves.
  
• Animals collected include:-arthropods, earthworms and small vertebrates like lizards/chameleons/ rodents.
  
• Place in polythene bags and take to the laboratory.
  
• Stinging/poisonous insects killed using ether.
  
• Other animals are observed live and 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 covering, feathers, eyes, mouth, limbs, and other appendages,
  

The differences between animals and plants collected

Comparison Between Plants And Animals

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