Background Information

In a given species of organism several structural and functional similarities exist, even similarities in appearance are commonly observed even more closely when such organisms are from the same parents.

But no matter how similar in various respects, organisms of the same species do display remarkable differences even when of the same parents. It is such differences that are referred to as variation. Variation are differences observed in species of living thing which are caused by genetic inheritance and acquired characteristic due to environmental factors.

Variation due to genetic inheritance are due to New genetic combination during meiosis and fertilization in sexual reproduction and Spontaneous changes that occur in genes called Mutation.

Types of Variation

In a given population; Variations can show in characteristic feature and trait of an individual. Such variations are grouped into:

1. Morpholical variations and
2. Physiological variations.

Morphological variations is variation in physical or outward appearance of an organism. Examples of such variations are weight, height, colour, facial features, finger prints etc. Physiological variation is variation in behaviour, activities and bodily functions of organisms . For instance ability to roll tongue, behaviour patern, blood groups etc.

Variation can as well be categorized into continuous and discontinuous variations.

Continuous Variation: are those that have intermediate forms or features between one extreme and the other. Example are size, height, colour etc.

Discontinuous variation: are variation in those characteristic that have no intermediate form. Example Tasting T.T.C, tongue rolling, ear lobes etc.

Application of Variation

Knowledge derived from variation are applied in

1. Crime detection
2. Blood transfusion and
3. Determination of paternity

Crime detection:

Here fingerprint of an individual which is usually not exactly alike (except that of identical) are used. Amore reliable means is the DNAfingerprints. This is done by collecting the body cells left at the scene of the crime and its DNApattern is analysed. The method is very expensive.

Blood Transfusion:

People have different blood groups. Groups A, B, AB and O are the existing known group. Proper administering of blood transfusion requires that the right group should be administered to the recipient from the donor. Donor recipient compatibility which is tabulated below, helps to administer the right blood group during blood transfusion.

Detection of Paternity:

In this ease, Variation caused by inherited characteristic such as blood group, tongue rolling, DNAfingerprint etc can be used to know the paternity of a child when it is under dispute. Among all the methods that can be used, the best is DNAfingerprint.

Adaptation for Survival

Adaptation is known as a process by which a living thing become fitted to its environment so as to live successfully and reproduce. Organisms adaptation for survival are being affected by factors like variation, competition and natural selection.

Types of adaptations:

Adaptation can be seen as modification or changes in form, structure, functions and behaviours of organism which enables it to withstand environmental factors in its natural and changing environment. Adaptation can be in structure of an organisms (structural adaptation); It can be in behaviour (behavioural adaptations), It can also be in form of colour (adaptive colouration).

Structural Adaptation

Organisms can have body parts which are modified to fit its mode of life and activities such as obtaining food, conservation of water, regulation of body temperature, escape from predators and defense from invading enemies, securing mates etc.

Behavioural adaptations involves the mode of life of an organism and its response to changes on its environment. This includes:

Tropic, tactic and Nastic movements in plants such as movement of plant shoot to the direction of light, insect trapping movements of the leaves of the venus flytrap etc. behavioural adaptation in obtaining food such as foraging behaviour among organism like cheetah, which is a hunting carnivore, a spider which set traps for other smaller animals etc.

Escape and defence behaviour like rolling into a ball shape by a hedgehog when attacked; erratic flying of a butterfly to escape enemies,

Behavioural adaptations for withstanding unfavourable condition such as Hibernation aestivation and migration among ground squirrels toads and birds respectively.

Communication behaviour such as croaking of male toad to inform female toads of its identity and mating intension; bee dance on the surface of the honey combs of the hive informing other worker bees the distance and direction of food etc.

Caring for the young or parental care among birds and mammals.

Behaviours in finding males like the display of a peacock before a peahen etc

Adaptive Colouration: Adaptive colouration in organisms can be categorized into concealing coloration, warning colourations and mimicry.

Concealing colouration: This can be used in camourflage to enable both prey and predators not to be notified. Examples are : The green cuticle of the grasshopper which blends it with the grass; concealing colouration can also take the form of disruptive coloration as in the spots and stripes of the leopard, giraffe, tiger, zebra, counter shading, and colour change as in chameleon.

Warning Colouration: A colour signal which serves to warn or inform would be predators to avoid such animals because they have undesirable features, for instance colourful spotted marks on the wing cases of the foul tasting lady bird beetles, vivid green and orange patterns of some south American forest frogs which have deadly neuromuscular poisons.

Mimicry: Here colours and colour pattern are used by animals to feign to be another thing or another organism inorder to escape being prayed upon by predators to being notice as a predator.

Organic evolution (evolution of living things) is the whole lot of adaptive changes over a long period of time which leads to the development and transformation to a new species from earlier ones.

Theories of Evolution: The present day theories on evolution which is refered to as neo-Darwinism combines darwin's theory with our present day knowledge of genetics and molecular biology.

Darwins Theory: Darwings theory of natural selection whereby enivornmental pressure imposes a constrain in a population of organisms and those individuals with herited characteristics different from others (inherited variation) can withstand such pressure, survive and continue existence while other may go into extinction.

The theory can be itemized below in six points.

• Species are capable of producing a large number of offsprings.
• There is limited resources in nature
• Competition is inevitable for survival of offsprings in each generation.
• There is great variability in populations of organisms that no two individuals are the same. Much of this variability are inherited.
• The organisms that survive and produce offsprings are those that have inherited the most valuable traits for surviving in that particular environment.
• As this process continues for many generations, the population gradually becomes better adapted to the environment.

Darwin knew nothing about the modern day genetics but after this, modern day research and knowledge of genetics has led to modern view of evolution (Neo-Darwinism).

New Darwinism explains natural selection as a function of genetic variation but also goes on to identify mutation, Gene flow and gene drift as other natural forces that are responsible for evolutionary changes.

Evidence of evolution

1. Fosil records
2. Biochemical similarities.
3. Molecular records
4. Comparative anatomy and
5. Embryology

The above stated evidences has been proven to support the theory of evolution.

General Questions

1. Variation due to inherited characteristics are made possible by new genetic combinations that take place in sexual reproduction and

2. Classify each of these characteristic features and behaviours into the group they belong in the

8. The anti A serum would cause blood containing with antigen A to clump.

9. If a blood sample neither clumps with anti A serum nor with anti B serum, that blood sample will belong to group

10. The clumping of red blood cells is called

11. Group the following characteristics and behaviours into continuous ad discontinuous variation

1. Tongue rolling,
2. Size
3. Colour
4. Ear lobes
5. Ability to taste PTC (phenylthiocarbamide).

16 In crime detection and prove of paternity is most reliable

17 In blood transfusion, Group is a universal recipient.

18 Aggressive behaviour and territoriality are kinds of interference an organism exhibit on another to obtain a resource. They are observed in Competition

19 Variation which helps organisms to survive in their natural environments are said to have value.

20 Competition among members of the same species is called while that among members of different species is called

21 Write three structural features that are involved in regulating temperature in the body.

22. A chameleon displays an adaptive colouration of

23. Peck order is found among vertebrate societies while systems are found among insect societies.

24 State the four caste of a termite colon

25. State three ways by which bees communicate with each other

26. An error in the replication of genetic material which results to a spontaneous change in the genes is called

27. Certain substances and conditions that can increase the rate of mutation are called

28. The best known mutagen is

29. Wolves live in family units known as

30. __________ is the mutant Hemoglobin gene which though harmful, is naturally selected in west Africa sub region because of the immunity it provides against malaria.

Expression Exercise

1a. List three applications of variation

b. The bar chart below shows frequencies of ABO blood group in a particular country.
Use it to answer the questions that follow

c. Which blood group has the highest frequency of occurance?

d. Are anitigens found in the red blood cell of the blood group?

e. Explain why ABO (system) blood group is said to be a discontinuous variation

c Write down three animals that carry out concealing colouration in their adaptations.

3a. Write two remarkable differences between the behaviours and life history of a honey bee and those of a termite.

b. Explain the principles of natural selection in Darwins theory of evolution.

b. Write down four biological evidences to prove the reality of evolution.

Practical Activities

Finding out whether every body in the class can roll the tongue

(iv) Use your record to draw a bar chart showing the frequency of occurance of tongue rollers and non tongue rollers in the whole population of the class.

(v) What type of varaition did you investigate?

2. To find out variation in height

Materials Needed
Black board and chalk, centimeter scale graph paper

1. Pair up yourselves and let your partner read off your height in centimeter from a scale marked on the wall.
2. The teacher will write your height and that of other class members who equally did the same in pairs.
3. The same record from another class can also be taken by the teacher.
4. Group your records and use it to construct a histogram on graph paper
   (Do this in your biology practical note book), then answer the questions below.
5. By how much does height vary in the sample?

(ii) What is the proportion of very short or tall student compared to those of average height?

(iii) Does this variation investigated belong to morphological varaiation

(iv) Also is it continuous or discontinuous?

3. Discovering how finger prints vary

Material/Apparatus required

1. Board and chalk or marker
2. Ink pad
3. Plain white paper
4. Hand lens
5. Ruler

Methods

1. Wash your hand and dry it thoroughly.
2. Draw series of (or many ) squares of 2cm dimension on the piece of plain paper.
3. Press the thumb of your right hand on the ink pad so as to impress on it.
4. Thumb print on the square space you drew. Cause some (at least up to 20) other student to do the same.
5. Use the hand lens to examine the various finger prints and to categorize each of them according to how they look like (or very closely look like ) the ones on print on the book below.

(V) Your teacher can record the type of print made by each class member on the board

Questions

(i) Is your own finger print (thumb print) a loop whorl, double loop or arch?

(ii) State one use of finger print as in application of variation

(iii) From your findings and observations did two or more students fingerprints match each other in similarity?

(iv) Explain your answer in line with your knowledge of variation

Test of Practical Work

1a. What will be the result of treating a blood with antigen B in its red blood cell with a serum containing anti B

b. With which other blood group can you still obtain similar practical result.

c. Why is knowledge of blood group of an individual necessary before blood transfusion?

2.(b) Explain the significance of each type of bee dance and what it communicates to other bees (or worker bees)?

(c) How does each dance differ from each other in terms of the information it carries

NECO SSCE 2001
1. The weights, in kilograms, of a number of students in the same class were measured as shown

(a)i Group the data frequencies, using a class interval of five.

(ii) Placing the frequency along the y-axis and weight (kg) along the axis, prepare a histogram for the data.

(iii) How many students were weighted?

(iv) How many students fall within modal class?

(v) Calculate the average weight of the class

(b) what type of variation does this depict?

2. Place the thumb of your right hand, face-down on ink pad, exerting little bit of pressure on it.
Press the same treated thumb on your answer script, still exerting a little pressure. Observe the result on your answer script. Wash your thumb immediately after the experiment.

b. What name is given to the observation on your answer script? Mention one use of it to mankind give reason.

c. What area in the study of biology is your observation associated with?

3a. What type of variation is height

3b. Mention three other examples of the type of variation in 3a

June 2000 Q2
4. 2. The heights(cm) of 20 students in a class are as follows: 155, 157, 151, 169, 162, 151, 149, 165, 169, 176, 169, 179, 173, 169, 157, 155, 165, 157, 197 and 162.

Use them to answer the following questions:

(a) Make a frequency distribution table of class intervals of five of the different heights.
(Draw in your biology practical notebook).

(c)i Construct a histogram showing the variation of height, among the students with the heights on the horizontal axis and number of students on the vertical axis

ii. How many student fall into each of the height extremes?

iii. How many students have height between the shortest and the tallest student

iv. Find the difference in height between the shortest and the tallest student

(d)i. What type of variation is height?

ii. Mention three other examples of the types of variation in (d)(i) above.

June 2009 WASSCE BIOLOGY 1 PRATICALS-QUESTION

You are provided with water lettuce as specimen A, Cactus as specimen B, Talinum (waterleaf) as specimen C

1. Study specimens A,B and C carefully and use them to answer questions (a) to (d).
(a) State the habitats of specimens A,B and C. [3marks]

(b) State (i) two observable features each of specimens A, B,C;
(ii) how the features in 1(b)(i) adapt the specimens to their habitats.[12marks]

(c) State three observable differences between specimens A,and C. [3marks]

(d) Make a drawing 8-10cm long of specimen C and label fully. [7marks]