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Variation: Types, Sources, Application [Biology Tutorial]

JAMB UTME Tutorial on Biology: Our topic today is on Variation. We will discuss the Types, Sources and Application.

Today is DAY 4 on our JAMB FREE TUTORIAL for JAMB UTME candidates. This is the second topic for Biology. Our topic today is VARIATION. We will show you the types, sources and application. In the application you will see the various blood groups and lots more.

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Not let’s start the tutorial for today!


Variation is the difference among member of population or members of different population.

Types of Variation

(1) Morphological or Physical Variation:

This is concern with the physical appearance of an organism.

In animal such morphological includes:

  • Height
  • Body weight
  • Finger prints
  • Colour of skin, eye and hair
  • Sexes in male and female
  • Shape of head, fingers, nose, mouth etc.

In plant such morphological variation includes:

  • Growth rate and vigour
  • Height
  • Sexes in flowers
  • Colour of leaves

All these morphological or physical variation are said to be continuous variation, this is because they are always expressed in every generation of a population.

(2) Physiological Variation:

This variation is concern with functions of organs in organism.

In animal, such physiological variation includes:

  • Ability to roll the tongue
  • Ability to move pinna of the ear
  • Present or absent of ear lobe
  • Blood group
  • Sixth finger
  • Ability to taste certain chemicals such as phenylthiocarbamide (PTC).

In plant such physiological variation includes:

  • Colour in flowers.
  • Shape of leaves, fruits and seeds.

All these physiological variation are said to be discontinuous variation as they are not always express in every generation of a population.


All living things are product of nature and nurture.

(1) All these variation which an organisms acquires naturally from the parents through their garments or sex cells are said to be E.g.;

  • Intelligent quotient (IQ)
  • Colour of the skin, hair and eye.
  • Finger prints etc.

The variation are said to be heritable because they are controlled by genes or DNA molecules carried in the chromosomes hence, such variation are said to genotypic.

(2) All these variation which an organisms acquire as a result of the influence of nurture or environment are said to be non-heritabl

e.g.; Development of large muscles through exercise and sports. The variation are non-heritable because they are not controlled by genes or DNA molecules and therefore cannot be transmitted by parent to their offsprings or progeny. Hence, such variation are said to phenotypic.

Sources of Variation

  • During crossing over or recombination of non-sister chromatids during meiosis.

Mutation: this is the sudden change in the structure of chromosomes. Mutation can be

  • Chromosomal mutation
  • Gene mutation

Chromosomal mutation is the great source of aberration in population.

Note: Mutation is the greatest source of variability in population. Without mutation, life will tend to cease.


Certain variation that are morphological or physiological are applied in solving certain human problems in the society i.e. solving certain human society problems. Such problems includes:

(1) Crime Detection;

  • Finger prints are use in detecting criminals as no two individuals even of the same parents have the same finger prints.

Classes of Finger Prints

This is group into four classes, arrange in sequential order:

  • Arches
  • Loops
  • Whorls or rings
  • Compounds
  • Blood stains in places of murder are used in detecting the murderer.

(2) Blood Transfusion

The knowledge of blood group has successively help in the transfer of blood from one individual to another. To avoid agglutination during blood transfusion, a preliminary step has to be taken by carrying out a blood test or blood matching. The table below shows the blood group that donates blood to another blood group and receives blood from another blood group.

Under emergency, blood group AB can receives blood from all the blood groups and therefore is regarded as universal recipient while blood group O can donate blood to all the blood groups and therefore is regarded as universal donor.

Please Note:

  • Blood group A have antigen A in their red blood cells and antibody B in the blood serum.
  • Blood group B have antigen B in their red blood cell and antibody A in their blood serum.
  • Blood group AB have antigen A and B in their red blood cell but do not have antibody in their blood serum.
  • Blood group O have no antigen in the red blood cell but have antibody A and B in their blood serum.

(3) Determination of Paternity: The knowledge of chromosomes and the genes or the DNA molecules they carry tremendously help in determining the father of a child through their genotype.

(4) Medicine: In the field of medicine, genetic or hereditary principles are applied through genetic counselling so as to remove from the human world population the inheritance diseases such as sickle cell anaemia that are of great scourge to man.

(5) Agriculture: In the field of agriculture, the principles of heredity are applied through genetic engineering involving the use of DNA molecules to improve or crop and animal production.

In Crop Production: Genetic or hereditary principles are applied in

  • Increasing crop quality e.g. maize.
  • Increasing crop yield.
  • Improvement in crop variety e.g. variety of beans, rice, maize etc.
  • Production of crops that show resistance to adverse or unfavourable environmental condition and diseases. E.g. winter wheat that grows under severe cold condition.

In Animal Production or Husbandry: hereditary principles are applied in

  • Increasing quality of meat.
  • Increasing egg yield e.g. the poultry birds.
  • Increasing milk production.
  • Breeding of animals used for sports e.g. birds, dogs.
  • Production of farm animals that are resistance to attract adverse environmental condition and disease.




Use the following to test your Knowledge on VARIATION

Whorls ,arches,loops and compounds are types of variation in
A. Blood group
B. Eye colour.
C. fingerprints
D. Hair colour

2.An individual with blood group AB can receive blood from those in blood group(s)
A. A and B only
B. A,B,AB and O
C. A,AB and O only
D. AB only

3. To which blood group do universal recipients belong?
C. B
D. A

4. A dilute solution of phenylthiocarbamide tastes bitter to some people and is tastless to others. This is an example of
A. Taste buds variation
B. Discontinuous variation
C. Morphological variation
D. Continous variation

5. A phenotypic character with intermediate form that can be graded from one extreme to the other is referred to as
A. Discontinuous variation
B. Continous variation
C. A mutant
D. A genome

6. An accurate identification of a rapist can be carried out by conducting?
A. Blood group test
B. Behavioural traits test
C. DNA analysis
D. RNA analysis

Credit: This BIOLOGY tutorial was prepared by Ejimgini, Ozioma Promise a Biology/Chemistry Tutor.

Remember, we now have a JAMB CBT Practice App for UTME candidates. This App does not only have JAMB past questions and detailed explanation to answers, it also has study materials / textbooks (read any topic of your choice), JAMB Syllabus, JAMB Brochure/subject combination and access to latest educational news. For more details on how to get the APP, PLEASE CLICK HERE.

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Oladipupo ameerat success

What are the important of variation


I really appreciate tutor promise and the allschool team.
I enjoyed the lesson
Answers are. C,b,b,b,a,c.


Please, I don’t understand this expression, could you pls shed more light on it?
“Note: Mutation is the greatest source of variability in population. Without mutation, life will tend to cease.”


Why are these *Colour in flowers.
Shape of leaves, fruits and seeds* regarded as phisiological variation?
And as we know, they have to do with physical appearance of the plants.
Also, there is an intermediate between them such as we have it in height and weight of a plant.

Rauf samad


Rauf samad


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