The Class 12 Biology Practical on “Study of Plant Population Frequency by Quadrat Method” is an important experiment that helps students understand how plant species are distributed in a given area. This practical is commonly included in school field studies because it is simple, reliable, and provides valuable ecological insights.
AIM: Study the plant population frequency by quadrat method.
REQUIREMENTS:
Thread, nails, hammer, metre scale, paper, pencil
PROCEDURE:
1. In the selected site of study, hammer the nails firmly in the soil without damaging the
vegetation.
2. Fix four nails to make a square.
3. Tie each end of the nails using a thread, to make a 1 m X 1m quadrat.
4. Similarly, make nine more quadrats randomly in the site of study.
5. Select the plant species for study of the population frequency.
6. Observe the presence of species "A" in the first quadrat and mark it in the table
7. Similarly, check for the presence of species "A" in other quadrats respectively and
record the data in the table.
8. Observe the presence of species "B" in all quadrats and mark it in the table.
9. Repeat the same procedure for species C and record the data in the table.
10. We can calculate the frequency of plant populations by this equation:
11. Percentage Frequency=(Number of sampling units in which the species occurs)/(Total
number of sampling units employed for the study)* 100
OBSERVATION:
of sample quadrats.
CONCLUSION:
The plant population frequency is the highest in species C and the least in species A. It shows how many times a plant species is present in the provided number of sample quadrats.
PRECAUSTION:
1. Measure the quadrat accurately,
2. Quadrats should be studied from one area only, with uniform distribution of plants
Class 12 Biology Lab Manual – Final Practical's | Complete Lab Experiment File
A. List of Experiments
1. Prepare a temporary mount to observe pollen germination.
2. Study the plant population density by quadrat method.
3. Study the plant population frequency by quadrat method.
4. Prepare a temporary mount of onion root tip to study mitosis.
5. Isolate DNA from available plant material such as spinach, green
pea seeds, papaya, banana etc.
B. Study and observe the following (Spotting):
1. Flowers adapted to pollination by different agencies (wind, insects, birds).
2. Pollen germination on stigma through a permanent slide or scanning electron
3. Identification of stages of gamete development, i.e., T.S. of testis and T.S. of
ovary through permanent slides (from grasshopper/mice).
4. Meiosis in onion bud cell or grasshopper testis through permanent slides.
5. T.S. of blastula through permanent slides (Mammalian).
6. Mendelian inheritance using seeds of different colour/sizes of any plant.
7. Prepared pedigree charts of any one of the genetic traits such as 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. Models specimens showing symbiotic association in lichens, root nodules of
leguminous plants, and parasitic mode of nutrition shown by Cuscuta on host.
11. Flash cards / models showing examples of homologous and analogous organs.
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