Teacher Edition Variation

PANITIA BIOLOGI NEGERI KELANTAN 2007

CHAPTER 15: VARIATION

Multiple Choice Questions

For questions 1 to 10 each question is followed by four alternative answer, A,B,C or D. Choose

one correct answer for each question and blacken the corresponding space in your objective

answer

6.1 Understanding Variation In Organisms

6.2 Understanding The Causes Of Variation

6.3 Be Respectful Towards One Another Despite Variation

1. Which of the following examples are continuous variation?

I Hand span

II Fingerprints

III Tongue rolling

IV Intelligence

A I and II

B I and IV

C II and III

D II , III and IV

2.

From the dialogue above, genetic factors occur during ………………

I Nutrition

II Mutation

III Random fertilisation

IV Crossing over in meosis 1

A I and II

B III and IV

C II , III and IV

D I , II , III and IV

BIOLOGY QUESTIONS BANK15-1

Teacher : “ What are the causes of variations ? “

Anisah : “ Variations can be caused both by genetic factors and environmental factors “ .

Teacher : “ Yes , very good “ .


3.

Type Of

Finger printsCurves Right Loops Whorl Left Loops

Number of

students

12 16 4 8

TABLE 15.1

A class of 40 students did an investigation of variation on types of fingerprints among

them. They recorded the information and gathered the result in table 15.1 . What type

of variation is shown?

A Continuous variation

B Discontinuous variation

C Genetic variation

D Environmental variation

4.

Number of

chromosomes

Chromosomes

involved

Sex

47

( 44 + XXY )

An extra X chromosomes Male

DIAGRAM 15.1

Base from diagram 15.1, which of the following diseases is caused by chromosomes

mutation in human ?

A Down’s syndrome

B Turner’s syndrome

C Klinefelter’s syndrome

D Albinism syndrome



5. Diagram 15.2 shows a change in the chromosome structure caused by chromosomal

mutation .

a

DIAGRAM 15.2

The changes in the chromosome is be due to …………………

A Deletion

B Duplication

C Inversion

D Translocation

6. Two siblings have different abilities to roll their tongue . What is the cause of this trait ?

A Diet

B Genetic factors

C Environmental factors

D Deletion of parts of the chromosomes

7. Which of the following events are the result of chromosomal mutation in human ?

I One less chromosome in the cell

II Deletion of parts of the chromosomes

III An extra sex chromosomes in the cell

IV Genetics recombination due to crossing over

A I and II

B I , II and III

C II , III and IV

D I , II , III and IV


D

E

H

G

F


8. Which of the following variation is influenced by environmental factors ?

A Blood group

B Rhesus factor

C Type of earlobe

D Colour of the skin

9. What is meant by mutation ?

A Changes to the chromosomes after fertilisation

B Changes to the chromosomes due to crossing over

C Changes to the chromosomes due to recombination

D Sudden changes to the chromosomes because of mutagens

10. In an investigation carried out to investigate variation , the following characteristics are

obtained :

An example of the variation investigated is ………..

A Intelligence

B Eye colour

C Types of fingerprint

D Blood group


No distinct differences Has intermediate characteristic Normal distribution graph obtained


Structured Items

Answer all questions. Write your answers in the spaces provided in the question paper.

6.1 Understanding Variation In Organisms

6.2 Understanding The Causes Of Variation

6.3 Be Respectful Towards One Another Despite Variation

1.

TABLE 15.2

Ability to roll tounge Group of people

Able to roll tongue P and R

Unable to roll tongue Q and T

TABLE 15.3

(a) What is the type of variation shown by the table 15.2?

BIOLOGY QUESTIONS BANK

Group of

people

P Q R T

Height range 151-155 cm 156-160 cm 161-165 cm 166-170 cm

Number of

person

6 9 10 5

15-5


Trait Type of variation

Height Continuous variation

Tongue Rolling Discontinuous variation

[2 marks ]

(b) Base from the investigation, what is meant by continuous variation ? [1 mark]

There is a complete range of measurements for height from 151 cm to 170 cm

(c) (i) Using results from table15.2, draw a histogram of number of people against the

height range (cm).

(ii) Joint the midpoint of each bar to draw a smooth curve .

(iii) Using results from table 15.3, plot the bar graph of number of people against the

ability to roll tongue. [5

marks]

Number of people

10

8

6

4

2

Height range (cm)

151- 156- 161- 166-

155 160 165 170



Number of people

14

12

10

P + R Q + T Ability of tongue rolling

Able Unable

(d) State the factor that can cause this type of variation for each trait stated.

Traits Factors that cause variation

Height Genetic and environmental factor

Tongue Rolling Genetic factor

[2 marks ]

(e) Explain how the students conducted the investigation to determine the type of variation

in the height of people ?

-The height of each person are measured using the height

measurement ruler.

- The height is grouped into five classes of height range

- The height range is recorded in a frequency table.

- A histogram is drawn to show the normal distribution

[3 marks ]



2.

DIAGRAM 15.3

Diagram 15.3 shows a group of children with a genetic disease due to mutation .

(a) State the genetic disease based on diagram 15.3 . [1 mark ]

Down’s syndrome

(c) What is the type of that mutation ? [1

mark ]

Chromosomal mutation

(d) How many chromosomes do the children have ? [1

mark ]

47 chromosomes

(e) Mutation are caused by agents called mutagens .

Give two examples of mutagens . [2 marks ]

Radioactives radiation , X-rays , ultraviolet light , gamma rays , chemical

substances , formaldehyde , pesticides .

( f ) How do mutagens caused mutation ? [2 marks]

Chromosomal mutation -changes in the structure of chromosomes or the

number of chromosomes.

Gene mutation -Chemical change in the structure of gene, it may also alter

the DNA or genetic code.



( g ) Table 15.4 below shows genetic diseases caused by chromosome mutation.

Fill in the blank by using the word given .

Male Klinefelter’s syndrome Female Jacob’s syndrome

Turner’s syndrome Male and Female

Disease

Number of

Chromosomes

Chromosomes

involved Sex

Turner’s

syndrome

( 44 + XO ) Absence of one sex

chromosome Female

Klinefelter’s

syndrome

( 44 + XXY ) An extra X

chromosomes Male

TABLE 15.4 [4 marks ]



Essay Items.

1.

DIAGRAM 15.4

Type of

finger

prints Curves Right Loops Whorl Left Loops

DIAGRAM 15.5

Diagram 15.4 and 15.5 shows two different variation among human beings.

(a ) Determine the type of variation in Diagram 15.4 and 15.5. Give reasons.

[4 marks]

(b) (i) What are the differences between continuous and discontinuous variation?



(ii) State the factors that cause variation in humans .

[6 marks]

(c) Base from the statement above , explain the three sources of genetic factors

during sexual reproduction [10 marks]

Answer .

No. Answer Mark

1(a) -Diagram 15.4 is (height ) continuous variation

-Because the differences between individuals are slight

and can be changed .

-Diagram 15.5 is ( type of fingerprints ) Discontinuous

variation

-Because the differences between individuals are obvious

and cannot be changed

1m

1m

1m

1m

(b)(i)

Continuous variation Discontinuous variation

Differences between

individuals are slightly

with intermediates

There is a complete range

of measurements from

one extreme to the other

for a particular

characteristics.

Differences between

individuals are obvious

There is no gradual

change between two

extremes

2m

2m


There are three sources of genetic factors in sexual reproduction events :

Crossing over during meiosis 1 Independent assortment during meiosis Random fertilisation


(b)(ii) Genetic factors

environmental factors or both.

1m

1m

(c) Crossing over during meiosis

-During prophase I of meiosis, two homologous chromosomes

are paired up in a bivalent.

-The non-sister chromatids break at the chiasma.

-Segment of the chromatids exchange places .

-The exchange of genetic materials between the chromatids

results in new , different genetic combination of genes from the

parents.

-The new genetic combination result in variation .

Independent assortment during meiosis

-During metaphase I of meiosis , homologous chromosomes

arrange themselves randomly at the equator.

-The random arrangement and separation of each homologous

pair is independent of one another.

-Independent assortment produces various genetic

combinations in the gametes .

Random fertalisation

-Each gametes has a unique set or combination of genes .

-A male gamete can fertilise any of the female gametes, .

-so, the fertalisation between a male gamete and a female

gamete occurs randomly.

-As a result , a zygote is formed with variety of gene

combination.

-With random fertilasation , variations occur in the offspring.

1m

1m

1m

1m

1m

1m

1m

1m

1m

1m

1m

1m

1m

( Max:

10 marks )

End Of Questions


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