EXERCISE 1

July 3, 2013 TYPES OF VARIATION

Differentiate the types of variations

Illustrate the variations noted in the specimen

and,

Appreciate the beauty and wonders of the

things around brought by the types of

variations

OBJECTIVES

variation

basic quality of an organism

phenotype

an individual’s observable trait (height, eye color, and blood

type)

genotype

genetic contribution of the phenotype; a collection of genes; a

combination of alleles for a particular gene

GENOTYPIC VARIANCE

variation in phenotype caused by genetic make-up additive variance (deviation from mean phenotype due to

inheritance of a particular allele; average differences)

dominance variance (expression is not equal)

epistatic variance (interaction with alleles but associated with different loci)

ENVIRONMENTAL VARIANCE specific environmental variance (deviation from mean due to envt

conditions uniquely experienced by individual)

general environmental variance (non-genetic sources experienced by multiple individuals in population)

genotype by environment interaction (unique or diff responses of genetic lines to GEV)

MAJOR CAUSES OF VARIATION

In a CORN, genes A and B control the yield of the corn.

A – 2 corns a – 1 corn

B – 6 corns b – 3 corns

each allele will contribute to the yield of the corn

AaBb X AaBb AABB - 16 (2+2+6+6) AABb - 13 AABb - 13

AaBB - 15 Aabb - 9 AaBb - 12

aaBB - 14 aabb - 8 aaBb - 11

ADDITIVE VARIANCE

A plant produces white flowers if its genotypes are A1A1 and

red flowers if its genotypes are A2A2

we would assume that A1A2 leads to pink flower but in

dominance variance there is NO MIDPOINT

If A2 is dominant, A1A2 would produce red flowers

DOMINANCE VARIANCE

In the same flower, a B1 gene produces pigment whereas a B2

gene does not produce any pigment (flower appears white)

A2A2B1B1 – red flower

A1A1B2B2 – white flower

A2A2B2B2 – white flower

EPISTATIC VARIANCE

5 pcs common fruit belonging to same species

5 pcs mayana, San Francisco, or Duranta leaves

5 pcs flowers of any plant species

2 groups of 5 invertebrates

Drawing materials and coloring pens

ruler

MATERIALS

A. Variation in plants

Examine the 5 fruits, the 5 leaves and the 5 flowers

of the plant specimens that you brought. Note the

variations in size, shape, color, and their other

features.

Illustrate and list down at least 5 variations that you

have observed in each of the specimens.

Compute for the total magnification of each

specimen.

PROCEDURE

B. Variations in animals

Do the same in your animal specimens. Observe not only its

morphological or anatomical variations but also their

similarities and differences physiologically, behaviorally and

sexually.

Compute for the total magnification of the specimen.

All drawings must be of 50 mm. in length and in width.

Computations about reduction and magnification must be

included. Determine if the specimen is magnified or reduced.

PROCEDURE

Name Date

Course/Yr/Section

Types of Variation

A. In Plants

1. Fruits of

(illustrations)

Similarities Differences

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Computations of magnification:

FORMAT

Types of Variation

2. Leaves of

(illustrations)

Similarities Differences

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Computations of magnification:

FORMAT

Types of Variation

3. Leaves of

(illustrations)

Similarities Differences

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Computations of magnification:

FORMAT

Types of Variation

B. In animals

1. (Common name: _________)

(illustrations)

Similarities Differences

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Computations of magnification:

FORMAT

Types of Variation

B. In animals

2. (Common name: _________)

(illustrations)

Similarities Differences

1. 1.

2. 2.

3. 3.

4. 4.

5. 5.

Computations of magnification:

FORMAT

1. What is variation. Give its importance.

2. What are the possible causes of variations? Give specific examples.

3. How would you know or identify if the cause of variation is genetic, environmental, or both?

4. Classify these variations as to “species characteristics” or “individual characteristics”.

Thorns in the stalk of the rose flower

Body size of ants

Color of apple skin

Color mosaic in San Francisco leaf

Number of body segments in worm

QUESTIONS

Make a survey of at least ten 2 nd or 3 rd year college students.

Note their sex, age, height, weight, and thumbprint.

Fill out Table 1

With the guide, classify the dif ferent surveyed thumbprints.

Summarize the data gathered on age, height and weight and

complete Table 2

Make a list of twenty (20) human traits and classify them as

to morphological, physiological, sexual or behavioral

variations. Fill out Table 3.

CONT. HUMAN VARIATIONS

FINGER PRINT CLASSIFICATION

Start collecting wild-type fruit flies

Place banana or its peel in a jar and expose near a garbage

can.

Observe frequently until enough fruit flies are trapped in the

jar. Cover with paper and poke the paper with pin (enough to

produce air circulation) Secure the paper with rubber band. Do

not keep in locker or expose in direct sunlight. Keep in room

temperature.

Keep collecting for culturing.

REMINDERS

Bring:

Samples of the fruit fly.

Hand lens

cotton balls

scissor

scotch tape

face mask

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