INDEX

S. No. Name of the Experiment Page No. Date of Signatures

Experiment

CORE EXPERIMENTS

1. To prepare a temporary mount to observe

pollen germination.
2. To study the plant population density by
quadrat method.
3. To study the plant population frequency by
quadrat method.
4. To prepare a temporary mount of onion root
tip to study mitosis.
5. To isolate DNA from available plant material
such as banana.
SPOTTING
1. Flowers adapted to pollination by different
agencies (wind, insects, birds).
2. Pollen germination on stigma through a
permanent slide or scanning electron
micrograph.
3. T. S. of Testis and T. S. of Ovary through
permanent slides (from grasshopper/mice)
4. Meiosis in grasshopper testis through
permanent slides.
5. T. S. of blastula (Mammalian) through
permanent slide.
6. Mendelian inheritance using seeds of different
colour/sizes of any plant.
7. Prepared pedigree charts on rolling of tongue,
blood groups, ear lobes, widow’s peak and
colour blindness.
8. Controlled pollination- emasculation, tagging
and bagging.
9. Common disease causing organisms like
Ascaris, Entamoeba, Plasmodium, any fungus
causing ringworm through permanent slides,
models or virtual images or specimens.
Comment on symptoms of diseases that they
cause.
10. Flash cards models showing examples of
homologous and analogous organs.
CORE EXPERIMENTS
 EXPERIMENT NO. 1

AIM: To prepare a temporary mount to observe pollen germination.

REQUIREMENTS: Given flower Hibiscus, sucrose (10g), boric acid (10g), potassium nitrate
(20mg), magnesium sulphate (30mg), distilled water, glass rod, cavity slide, brush, petridish,
dropper, cover slip and compound microscope.

PROCEDURE:

• Prepare a nutrient solution by dissolving 10g sucrose, 10g boric acid, 20mg
potassium nitrate and 30 mg magnesium sulphate in 100ml of distilled water in a beaker.
• Using a glass rod, stir the solution to mix it well.
• Put 2-3 drops of nutrient solution on a cavity slide with the help of a dropper.
• Take a fresh mature flower and remove anthers from it and crush them on a slide.
• Collect the pollen grains with the help of a brush and dust them in the cavity of slide
filled with nutrient solution.
• Put cover slip over it gently and leave it for 10 minutes.
• Observe the slide under microscope after every 5 minute to see the pollen
germination.
OBSERVATIONS:
• The pollen grains take up the nutrient solution and start germinating.
• Some pollen grains are in their initial stages of germination.
• Other pollen grains have quite long pollen tube containing tube nucleus and two
male nuclei.
PRECAUTIONS:
• The pollen germination medium should be freshly prepared.
• Only a few pollens should be dusted in a nutrient medium on slide.
• Pollens from different flowers should not be mixed.
• The number of germinated pollen grains should be counted carefully.
• The slide should not be disturbed.
 EXPERIMENT 2
AIM: To study the plant population density by quadrat method.
REQUIREMENTS: Metre scale, thread, nails, hammer, paper, pencil, hand lens.
PROCEDURE:
• Select a field to study the plant population density.
• Measure 1m × 1m area with the help of metre scale in the field to make a quadrat.
• Fix four nails with the help of hammer in the selected area at the corner of the
quadrat and tie each end of the nails using thread.
• Similarly, make nine more quadrats randomly in the field of study.
• To make the counting easy divide the quadrat further to make smaller squares.
• Count and mention the number of plants of a particular species in a square and
similarly mention the number of plants of another species if present.
• Now, count and add the total number of a particular plant species of all the squares
to get the total number of a particular plant species of the quadrat.
• Repeat the experiment for the other quadrats also.
• Calculate the population density of a plant species in a given field using the formula
given below:
Population Density = Total No. of plants in all quadrats/Total No. of quadrats studied
OBSERVATIONS: There will be differences in the species composition in the quadrats made
in shady areas, exposed areas with bright sunlight, dry or wet areas.
S. Name No. of plants per quadrat Total No. of Total No. Population
No. of the individuals of Density
species in all the quadrats (N= S/Q)
quadrats studied
(S) (Q)

1 2 3 4 5 6 7 8 9 10
1. A 3 - - 3 - - - - - - 06 10 0.6
2. B 3 2 - - 3 - - - - - 08 10 0.8
3. C 3 2 5 6 4 2 2 8 - - 32 10 3.2
4. D 4 1 5 - 2 2 4 4 5 - 27 10 2.7
5. E 5 - 5 - 3 4 4 3 4 - 28 10 2.8
6. F 6 - 6 - 5 3 2 - - - 22 10 2.2
7. G 4 4 - - - 3 - 5 - - 16 10 1.6
8. H 6 6 3 5 4 2 6 - - - 32 10 3.2
9. I - - - - - - - - 5 4 09 10 0.9
PRECAUTIONS:

• The measurements of the quadrats should be accurate.

• Count the individuals of one plant species at a time.
• Carefully count the number of individuals of each species.
 EXPERIMENT 3
AIM: To study the plant population frequency by quadrat method.
REQUIREMENTS: Metre scale, thread, nails, hammer, paper, pencil, hand lens.
PROCEDURE:
• Select a field to study the population frequency of plants.
• Measure 1m × 1m area with the help of metre scale in the field to make a quadrat.
• Fix four nails with the help of hammer in the selected area at the corner of the
quadrat and tie each end of the nails using thread.
• Similarly, make nine more quadrats randomly in the field of study.
• Select the plant species for the study of population frequency.
• Observe the presence of species ‘A’ in the first quadrat and make it in the table.
• Similarly check for the presence of species ‘A’ in other quadrats respectively and
record the data in the table.
• Repeat the same procedure for species ‘B’, ‘C’ etc. and record the data in the table.
• Calculate the percentage of frequency for a species using the formula given below:
Frequency % = Total No. of quadrats in which species appeared/Total No. of quadrats
studied × 100
OBSERVATIONS: There will be the difference in the species composition in the quadrats
made in shady areas, exposed areas with bright sunlight, dry or wet areas.
S. Name No. of quadrats employed in No. of Total No. Frequency %
No. of the the study (Q) quadrats in of (N/Q × 100)
species which the quadrats
species are studied
present (N) (Q)

1 2 3 4 5 6 7 8 9 10
1. A 3 - - 3 - - - - - - 2 10 20
2. B 3 2 - - 3 - - - - - 3 10 30
3. C 3 2 5 6 4 2 2 8 - - 8 10 80
4. D 4 1 5 - 2 2 4 4 5 - 8 10 80
5. E 5 - 5 - 3 4 4 3 4 - 7 10 70
6. F 6 - 6 - 5 3 2 - - - 5 10 50
7. G 4 4 - - - 3 - 5 - - 4 10 40
8. H 6 6 3 5 4 2 6 - - - 7 10 70
9. I - - - - - - - - 5 4 2 10 20
PRECAUTIONS:
• The measurements of quadrats should be accurate.
• One individual of the species should be counted only once in the quadrat.
• The vegetation should not be changed while laying the quadrats.
 EXPERIMENT 4

AIM: To prepare a temporary mount of onion root tip to study mitosis.

REQUIREMENTS: Onion bulb, conical flask to germinate onion root tips, blade, needle,
forcep, dropper, watch glass, glass slide, coverslip, N/10 HCl, acetic acid, ethanol,
acetocarmine stain, distilled water, blotting paper, spirit lamp, and compound microscope.

PROCEDURE:

• Take a healthy medium- sized onion bulb and carefully remove the dry old roots
attached to it using a sharp blade.
• Grow root tips by placing the onion bulb in a conical flask filled with water.
• Keep them in this position for 5-6 days. New roots may take 5-6 days to grow.
• Cut off 2-3cm of freshly grown roots and let them drop into a watch glass.
• Using a forcep, transfer them to a freshly prepared fixative of aceto alcohol (glacial
acetic acid and ethanol in 1:3 ratio) and help the root tips in the fixative for 24 hours.
• Wash the root tips with water and store in 70% alcohol.
• Rinse the fixed onion root tips in water.
• Using a forcep, take one root and place it on a glass slide.
• Using a dropper, place one drop of N/10 HCl on the root tip followed by 2-3 drops of
acetocarmine stain. Leave it for 5-10 minutes.
• Warm the slide on spirit lamp. Care should be taken that the stain should not be
dried up.
• Carefully blot the excess stain using blotting paper.
• Using a blade, cut the comparatively more stained (2-3mm) tip portion of root and
retain it on slide and discard the remaining portion.
• After 10-20 seconds, put one drop of water on the root tip.
• Mount a coverslip on it using a needle.
• Now slowly tap the coverslip using the blunt end of a needle so that the
meristematic tissue of the root tips below the coverslip is properly smashed and spread as a
thin layer of cells.
• Now, gently warm the slide over a flame for few seconds. Place the slide under
compound microscope and observe the different stages of mitosis.
OBSERVATIONS:
Interphase
• It is a resting phase between two mitotic divisions.
• The cell appears to be inactive or in resting stage but is metabolically the most active
and prepares the cell for next mitotic division.
• This phase is divided into G1, S and G2 phase.
• Nuclear membrane and nucleolus are clearly visible.
• Chromosomes do not appear to be clear structures and appear in the form of a
reticulum made of chromatin.
Prophase:
• Chromatin network gets condensed and appears as long thread- like structures
called ‘Chromosomes’.
• Chromosomes become coiled, shortened and more distinct.
• Each chromosome consists of two longitudinal threads called ‘chromatids’.
• Both chromatids are attached to each other by centromere and are known as sister
chromatids.
• Nuclear membrane and nucleolus disappear.
• Spindle fibres begin to develop.
Metaphase:
• Chromosomes become shorter and thicker and hence become distinct and clearly
visible under compound microscope.
• Chromosomes align themselves on the equatorial plate. Their chromatids are
directed towards the poles.
• Out of two chromatids of each chromosome, one chromatid faces one pole and the
other faces the opposite pole.
• Spindle fibres attach the centromeres to the opposite poles.
Anaphase:
• Two sister chromatids of each chromosome separate due to the splitting of
centromere and move towards the opposite poles.
• Spindle fibres attach to the centromeres, shorten and pull the chromatids to the
poles.
• At the end of metaphase, two groups of chromosomes are formed at each pole. The
number and types of chromosomes at each pole is same as the parent nucleus.
Telophase:
• Chromosomes at the two opposite poles lose their individuality and look like a mass
of chromatin again.
• Nuclear membrane is reconstructed around each group of chromosomes giving rise
to nucleus at each pole.
• Nucleolus reappears.
• Two daughter nuclei are thus formed appear to be similar to the parent nucleus both
quantitatively and qualitatively.
Cytokinesis: In plant cells, cell plate is formed in the middle after telophase. The plate can
be seen to extend outward to ultimately reach the margin of the cell and divide the cell
into two equal halves. Such cell plates are characteristic of plant cells.
RESULT: All the stages of mitotic cell division are clearly visible in the slide prepared from
onion root tips.

PRECAUTIONS:
• The base of the onion bulb should exactly be in contact with water, while growing
the roots.
• Always clean the slide and coverslip thoroughly before and after use.
• Heat the slide carefully so that the material may not be destroyed.
• Care should be taken that there should be no air bubbles under the coverslip.
• Press the coverslip gently until the cells are sufficiently separated and flattened.
 EXPERIMENT 5

AIM: To isolate DNA from available plant material (Banana).

REQUIREMENTS: A banana, a zip- lock plastic bag, table salt, liquid dishwashing detergent,
distilled water, 90% ethanol, beaker, test tube, spoon, funnel, filter paper, strainer,
toothpick.

PROCEDURE:

• Place a peeled banana in a zip- lock plastic bag and mesh the banana for 2-3
minutes.
• In a 250ml beaker, make a solution consisting of 10ml of liquid dishwashing
detergent and ¼ teaspoon (1.5g) of table salt.
• Add 100ml distilled water to the beaker to make a final solution. Dissolve the salt by
stirring slowly to avoid foaming.
• Add 100ml solution to the plastic bag containing meshed banana and mix the
content well.
• The dishwashing liquid detergent causes the cell membrane to breakdown and
dissolves the lipids and proteins of the cell by disrupting the bonds that hold the cell
membrane together. The detergent causes lipids and proteins to precipitate out of the
solution.
• The table salt enables nucleic acid to precipitate out of ethanol solution because it
shields the negative phosphate end of DNA, causing DNA strand to come closer together
and coalesce.
• Filter the mixture through a filter paper placed in a funnel or strainer over a new
1000ml beaker. While filtering the banana mixture, try to keep the foam from getting into
the filtrate.
• Dispense 5ml solution into a test tube.
• Take the chilled ethanol out of the freezer and add it to the test tube to create an
ethanol layer on top of about 1cm.
• DNA is not soluble in ethanol. When ethanol is added to the mixture, all the
components of the mixture, except of DNA, stay in the solution while the DNA precipitates
out into the ethanol layer.
• Let the solution stand for 2-3 minutes without disturbing it.
• Watch the white DNA precipitate out into the ethanol layer. When good results are
obtained, there will be enough DNA to spool on to a glass rod. DNA has the appearance of
white mucus.
OBSERVATIONS: The white DNA precipitates out into the ethanol layer, while all the other
components of the mixture, except for DNA, stay in the solution.
RESULT: The DNA has been isolated and it appears as transparent, slimy and white mucus.
PRECAUTIONS:
• Fresh plant material should be used for extraction of DNA.
• Beaker and test tubes must be thoroughly cleaned and dried.
• Always use distilled water for the experiment.
• Handle ethanol carefully because it is very flammable.
SPOTTING
 FLOWER ADAPTED TO POLLINATION BY WIND (MAIZE)

• Flowers are small and inconspicuous.

• Flowers are non- showy and non- brightly coloured.
• Flowers are devoid of scent and nectar.
• Flowers possess well- exposed stamens.
• Pollen grains are light, small and dusty. They are produced in large numbers.
• Stigma is hairy, feathery, branched and sticky to catch wind dispersed pollen grains.
 FLOWER ADAPTED TO POLLINATION BY INSECT (PEA FLOWER)

• Flowers are brightly coloured for attracting pollinating insects.

• Nectaries are present to attract insects.
• Nectar glands are placed in such position that an insect must touch both anther and stigma.
• Flowers have leading landing platform for the insects.
• Flowers show protandrous condition, i.e. stamens ripen before stigma to avoid self
pollination.
• Pollen grains are sticky.
 FLOWER ADAPTED TO POLLINATION BY BIRD (BIGNONIA)

• Flowers are big and brightly coloured.

• The flower parts are thick and leathery.
• Flowers produce abundant nectar and may also have certain edible parts. Birds visit
flowers for feeding on this nectar.
• Flowers are usually odourless.
 POLLEN GERMINATION ON STIGMA

• Many pollen grains are present over the stigma.

• Pollen grains absorb water and other substances such as sugars and organic acids
secreted by stigma.
• Some of the pollen grains are non- viable as they are not germinating and some of
the pollen grains are germinating over the stigma.
• The thin intine protrudes out through a germ pore into a slender pollen tube.
• Sugary substances secreted by the stigma stimulate further growth of the pollen
tube which gradually elongates, passes the style, enters the ovary and finally in the
ovule.
• The pollen tube carries with it a vegetative nucleus at its tip, followed by two male
gametes. It enters the ovule through the micropyle and reaches the egg through one
of the synergids.
 T. S. OF MAMMALIAN TESTIS

• T. S. of Testis contains highly coiled seminiferous tubules embedded in interstitial

space.
• Each seminiferous tubule is lined on its inside by germinal epithelium which divides
mitotically to produce male germ cells called ‘Spermatogonia’.
• Various tissues are seen in seminiferous tubules in the following order from
periphery towards lumen in different layers-
Spermatogonia (2n)
Mitosis
Primary Spermatocytes (2n)
Meiosis I
Secondary Spermatocytes (n)
Meiosis II
Spermatids (n)
Differentiation
Spermatozoa (n)
• Spermatozoa can be identified with their elongated head and long tail.
• Between the germinal cells, prominent pyramid shaped cells are present called
‘Sertoli cells’ which provide nutrition to the developing spermatozoa.
• ‘Leydig cells’ are seen in the interstitial space which secrete ‘testosterone’ hormone,
which is responsible for the development of male secondary sex characters.

T. S. of Testis (Mammal)
 T. S. OF MAMMALIAN OVARY

• T. S. of Ovary is lined by germinal epithelium.

• It consists of a mass of connective tissue and spindle- shaped cells, the two together
forming the stroma.
• The stroma consists of an outer ‘cortex’ and inner ‘medulla’.
• The stroma consists of many Ovarian/Graafian follicles at various stages of
development.
• Each follicle contains a large ovum surrounded by many follicle layers. The growing
ovarian follicles secrete ‘Estrogen’ hormone, which is responsible for the
development of female secondary sex characters.
• The stroma may contain a large mass of yellow cells called ‘Corpus luteum’ formed
by ruptured graafian follicle after the release of ovum.
• Corpus luteum secretes female sex hormone called ‘Progesterone’ which is
responsible for maintaining pregnancy.

T. S. of Ovary (Mammal)
 MEIOSIS IN GRASSHOPPER TESTIS

MEIOSIS I

Prophase I- It is a long and complex phase characterised by number of events. It is divided

into five main sub- stages-

(i) Leptotene
• Nuclear membrane and nucleolus are clearly visible.
• Fine network of thin chromatin threads is seen. These are chromatin fibres in
condensed form called ‘chromosomes’.
(ii) Zygotene
• Pairing of homologous chromosomes occur in this stage and they form ivalents.
• Each pair has two chromosomes similar in their length and their centromere
position.
• Chromosomes become more distinct as they become much shorter and thicker than
before.
(iii) Pachytene
• Homologous pairs of chromosome are clearly visible.
• Each chromosome has two chromatids and their each bivalent consists of four
chromatids. Hence, chromosome exhibit tetrad configuration.
• Crossing over, i.e., exchange of chromatid segments takes place between non- sister
chromatids of homologous chromosomes.
(iv) Diplotene
• Each homologous chromosome has two chromatids that show distinct separation
from each other except same points.
• The attachment points of two homologous chromosomes is called ‘Chiasmata’.
• The Chiasmata represent site of crossing over.
(v) Diakinesis
• Bivalents condense further and appear to be more shortened, thick and prominent
than before.
• Chaismata are clearly visible.
• All homologous pairs appear in a scattered form within the cell.
• Nuclear membrane and nucleolus disappear completely.
• Spindle formation can be seen in its early stages.

Metaphase I-

• The homologous chromosomes are still in pairs and are arranged along the
equatorial plane of the cell.
• At this stage, number of bivalents can be counted.
• Chiasmata may still be seen in few bivalents.
 • The spindle fibres attach themselves to the centromere of each chromosome pair.

Anaphase I-

• As a result of shortening of spindle fibres, paired chromosomes start separating.

• At the end of this stage, the chromosomes assemble at two poles. This results into
the reduction of chromosomes number to half.
• Each chromosome has two chromatids at this stage.

Telophase I-

• Chromosomes present at the two poles appear decondensed.

• The nuclear membrane is formed around the two new daughter nuclei.
• Nucleolus also reappears.
• Each nucleus formed has half number of chromosomes as compared to the nucleus
of the parent cell.

MEIOSIS II

• Meiosis II is similar to mitosis without duplication of DNA. It is divided into following

stages-

Prophase II-

• The chromosomes reappear as distinct rod- shaped or thread- like chromatin fibres.
• Each chromosome has two chromatids.
• Nuclear membrane and nucleolus start disappearing.
• The chromosomes become short by coiling and condensation.

Metaphase II-

• The chromosomes having two chromatids attach at the centromere are observed
arranged at the equatorial plane of the cell.

Anaphase II-

• The centromere of each chromosome divides into two, so that each chromatid gets
its centromere.
• Shortening of the spindle fibres occurs so that chromatids are pulled apart towards
their respective poles.
• The two chromatids of each chromosome after separation appear to lie at the two
poles of the cell.
Telophase II-

• The chromatids (now chromosome) on their respective poles, now uncoil and form
the chromatin network again.
• Nuclear membrane and nucleolus are reformed.
• Four haploid nuclei are seen in each cell (male or female gamete).

Leptotene

Zygotene

Pachytene
 Diplotene

Diakinesis

Metaphase- I
Anaphase- I

Telophase- I
Cytokinesis

Stages of Meiosis- II
 T. S. OF BLASTULA (MAMMAL)

• It is a spherical mass of about 64 cells.

• The outermost layer is zona pellucida followed by a layer of trophoblast.
• Within the envelope, a fluid- filled cavity called ‘Blastocoel’ is commonly found.
• Mass of cells inner to trophoblast is called ‘Inner cell mass’.
• The trophoblast layer gets attached to endometrium of the uterus and the inner cell
mass gets differentiated as the embryo.
• The side of the blastocyst to which the inner cell mass is attached is called the
‘Embryonic/Animal pole’, while the opposite side is called the
‘Abembryonic/Vegetative pole’.

T. S. f Blastula (Mammal)
MENDELIAN INHERITANCE USING SEEDS OF DIFFERENT COLOUR/SIZES OF ANY PLANT

(A) LAW OF SEGREGATION (MONOHYBRID CROSS) USING SEEDS OF DIFFERENT

COLOUR OF PEA PLANT

Phenotype of Parent Plants- Yellow seeds × Green seeds

Genotypes of Parent Plants- YY yy

Gametes- Y y

F1 Generation- Yy

100% Yellow seeds

On Selfing F1 Plants- Yellow seeds × Yellow seeds

Genotypes of F1 Plants- Yy Yy

Gametes- Y y Y y

F2 Generation-

Gametes Y y

Y YY Yy
Yellow Yellow seeds
seeds
y Yy Yy
Yellow Green seeds
seeds
Phenotypic Ratio- 3 : 1

Genotypic Ratio- 1 : 2 : 1
 (B) LAW OF INDEPENDENT ASSORTMENT (DIHYBRID CROSS) USING SEEDS OF
DIFFERENT COLOUR & SHAPE OF PEA PLANT

Phenotype of Parent Plants- Round Yellow seeds × Wrinkled Green seeds

Genotypes of Parent Plants- RRYY rryy

Gametes- RY ry

F1 Generation- RrYy

100% Round Yellow seeds

On Selfing F1 Plants- Round Yellow seeds × Round Yellow seeds

Genotypes of F1 Plants- RrYy RrYy

Gametes- RY Ry rY ry RY Ry rY ry

F2 Generation-

Gametes RY Ry rY ry

RY RRYY RRYy RrYY RrYy

Round Yellow Round Yellow Round Yellow Round Yellow
Ry RRYy RRyy RrYy Rryy
Round Yellow Round Green Round Yellow Round Green
rY RrYY RrYy rrYY rrYy
Round Yellow Round Yellow Wrinkled Yellow Wrinkled Yellow
ry RrYy Rryy rrYy Rryy
Round Yellow Round Green Wrinkled Yellow Wrinkled Green
Round Yellow Seeds= 9

Round Green Seeds= 3

Wrinkled Yellow Seeds= 3

Wrinkled Green Seeds= 1

Phenotypic Ratio- 9 : 3 : 3: 1

Genotypic Ratio- 1 : 2 : 1 : 2 : 4 : 2 : 1 : 2: 1
 PREPARED PEDIGREE CHARTS ON THE GENETIC TRAITS

(i) Pedigree Chart for Rolling of tongue-

• It is the ability of a person to roll the tongue in U-shape.

• It is controlled by a dominant allele ‘R’.

• The inability to roll the tongue is caused by an autosomal recessive allele ‘r’.

• Thus, both homozygous dominant (RR) and heterozygous (Rr) individuals are able to
roll the tongue, while homozygous recessive (rr) individuals are unable to roll their
tongue.

rr Rr

rr Rr rr rr rr rr

Rr rr rr rr rr
 (ii) Pedigree Chart for Widow’s Peak-

• It is a V- shaped hairline across the forehead.

• It is an autosomal dominant trait over straight line which is recessive.

• A person with a widow’s peak may have a genotype ‘WW’ or ‘Ww’, and the person
with a straight hairline will have a genotype ‘ww’.

Ww ww

Ww ww Ww ww Ww

ww Ww ww Ww ww
 (iii) Pedigree Chart for Ear Lobes-

• Ear lobes are controlled by a single gene.

• Ear lobes can be divided into two categories, free and attached.

• Free ear lobes are those that curve up between the lowest point of the ear lobe and
the point where the ear joins the head. Attached ear lobes blend in with the side of
the head.

• Free ear lobes (F) are the dominant trait while the attached ear lobes are the
recessive trait (f). In this case, there are two forms of dominance for unattached
ears, homozygous (FF) and heterozygous (Ff) dominant.

• Attached ear lobes are considered homozygous recessive (ff).

Ff ff

Ff ff Ff ff Ff

ff Ff ff Ff ff
(iv) Pedigree Chart for Blood Groups-

• ABO Blood Grouping in humans is a well known example of Co-dominance.

• Blood Group inheritance is independent of sex of the organisms.

• The ABO Blood groups are controlled by gene ‘I’ which have three alleles i.e. IA, IB
and i.

• IA and IB are co-dominant while IA and IB are completely dominant over i.

O AB

ii IA IB

O A A/B A

ii IA i IA i/IB i IA i

A A/B/O

IA i I A i/IA IA/IB i/IB IB/ii

 (v) Pedigree Chart for Colour blindness-

• Colour blindness is a sex-linked recessive disorder of humans.

• In this, the affected individual is not able to differentiate between red and green
colours.

• It results in the malfunctioning of one or more of the three types of cone cell
responsible for colour vision.

XY XcX

XcX XY XcY XY XcX/XX XcX XY

XcX/XX XcY XcX/XX XcY XY XcX/XX

 CONTROLLED POLLINATION- EMASCULATION, TAGGING AND BAGGING

Emasculation

• In this process anthers are removed from the flowers before their maturation so as
to check self- pollination.
• The anthers are removed with the help of sterilized forceps or scissors.
Bagging
• After emasculation the flowers are covered with small bags to prevent pollination
with undesired pollen grains.
• These bags are made up of polythene, butter paper, masculine cloth or parchment
paper.
• The bags are punctured or made perforated to provide aeration to the flower.
• The flowers of male parent are also protected in bags to prevent mixing of their
pollen grains with foreign pollens.
• When the stigma of emasculated flower attains receptivity, mature pollen grains
collected from anthers of the male parent are dusted on the stigma and the flowers are
rebagged.
Tagging
• A tag/label is fixed on the plant which contains the name of the female parent, name
of the male parent, the letter ‘X’ (to signify a cross) and the date of emasculation.
Tagging
 COMMON DISEASE CAUSING ORGANISMS
Ascaris lumbricoides: It is the endoparasite in the small intestine of human being and it also
infects pigs and cattle.
Disease caused: Ascariasis
Infection: It occurs through contaminated vegetables, fruits and water.
Symptoms:
• Generally a large number of adult Ascaris worm infect a single host and obstruct the
intestinal passage, thereby causes abdominal discomforts like colic pain.
• Patient suffers from diarrhoea, vomiting, weight loss etc.
• In children, mental efficiency is affected and body growth is retarded.

Ascaris lumbricoides
Entamoeba hystolytica: It is an endoparasite that resides in upper part of large intestine of
human.
Disease caused: Amoebiasis/ Amoebic dysentery
Infection: It occurs by ingestion of contaminated food and water.
Symptoms:
• Abdominal pain and cramps.
• Recurrent spindle of dysentery with blood and mucus in faeces.
• Cyst appears in faecal matter.
• It may enter liver, lungs and spleen.

Entamoeba histolytica
Plasmodium vivax: Plasmodium enters human body in sporozoite stage by the bite offemale
Anopheles mosquito.
Disease caused: Malaria.
Infection: It occurs through the bite of infected female Anopheles mosquito.
Symptoms:
• Early symptoms include restlessness, low appetite, slight sleeplessness followed by
muscular pain, headache and feeling of chillness.
• In response to chills, the body temperature starts rising and may reach 1000 F of
level.
• The patient sweats a lot and temperature lowers down.

Sporozoites of Plasmodium
Fungi causing Ringworm: Ringworm is an infectious disease caused by myotic infections of
keratinised area of body hair, skin scalp and nails. It is caused by fungi belonging to the
species of following genera- Microsporum, Trichophyton and Epidermophyton collectively
called as Dermatophytes.
Ringworm of Scalp:
Causal organism: Trichophyton, Microsporum
Symptoms: Formation of small yellowish cup- like crusts on sclap, hair become grey and
lustless. In severe cases, it leads to baldness.
Ringworm of Body:
Causal organism: Epidermophyton, Microsporum, Trichophyton
Symptoms: Cutaneous skin, infection appearing as flat ring- shaped lesions followed by
itching.
Ringworm of Foot:
Causal organism: Epidermophyton, Trichophyton
Symptoms: Scaling or cracking of skin especially between toes. Blisters containing thin
watery fluid may appear.
Ringworm of Nails:
Causal organism: Epidermophyton, Trichophyton
Symptoms: Nails become thickened, discoloured and brittle. Nails may also become chalky
and disintegrated.
Mode of Transmission: The physical contact with infected persons or their belongings may
spread infections. Usually scissors, clips remain contaminated with fungal spores and cause
infections in healthy persons.

Conidia of ringworm fungi

 HOMOLOGOUS AND ANALOGOUS ORGANS

HOMOLOGOUS ORGANS IN ANIMALS

Forelimbs of Seal, Bird, Bat, Horse and Man

• Forelimbs of Seal, Bird, Bat, Horse and Man are the examples of homologous
organs because they have the similar basic structural plan and same
developmental origin.
• In each case, the forelimbs consist of upper arm, forearm, wrist, palm and
fingers.
• The upper arm is made up of humerus, the forearm is composed of radius and
ulna, the wrist consists of carpals, the palm consists of metacarpals and the
fingers consist of phalanges.
• The skeletal parts of the forelimbs of all these vertebrates are similar in structure
and arrangement. They have pentadactyl limbs.
• The forelimbs of these animals perform different functions. Flippers of seal are
used in swimming, wings of bird and bat are used for flying, forelimbs of horse
are used for running, forelimbs of man are used for grasping things.
• Homology shows divergent evolution in which different modifications of organs
in a group have produced a variety of forms, adapted to different modes of life.
HOMOLOGOUS ORGANS IN PLANTS

Thorns of Bougainvillea and Tendrils of Passiflora

• Thorns of Bougainvillea and Tendrils of Passiflora are homologous organs in
plants as they have similar structural plan and developmental origin but perform
different functions.
• Thorns of Bougainvillea and Tendrils are the modified branches and arise from
axillary position.
• Thorns in Bougainvillea protect the plant from browsing animals whereas
Tendrils of Passiflora help in climbing up a support.
ANALOGOUS ORGANS IN ANIMALS

Wings of Birds, Bats and Insects

• Wings of Birds, Bats and Insects are analogous organs as they have different
basic structural plan and different origin but they perform similar functions.
• Wings of Birds and Bats originate from the forelimbs whereas wings of insects
are the extensions of the integuments.
• Wings of Birds, Bats and Insects perform the function of flight.
• Analogy shows convergent evolution which have evolved from separate ancestral
population. Convergent evolution is similarity developed in distantly related
groups as an adaptation to same function.
ANALOGOUS ORGANS IN PLANTS

Potato and Sweet Pea

• Potato and Sweet Pea are analogous organs as they have different basic structural
plan and origin but perform similar functions.
• Potato is a modified stem and it is the swollen tip of the underground stem to store
food. It has eyes which represent nodes which contain buds in their axil. Buds sprout
to give out new plants.
• Sweet Potato is a modified tuberous root with root hairs. It is swollen to store food.