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Study Plant Population Frequency by Quadrat Method is a process used by scientists to calculate the population frequency of the plants. The plant population is humongous in existence, but in ecology, knowing the plant population becomes a matter of concern.
- The Quadrat method helps tackle the problem of calculating plant population frequency.
- Frequency is defined as the degree of uniformity of an individual plant species.
- The quadrat method is helpful to know the follow-up of the frequency of a particular species in a given area.
- It is used for calculating plant density, plant biomass, and plant frequency.
- Study Plant Population Frequency by Quadrat Method helps analyse a large set of populations.
- Frequency depends upon the size and shape of the quadrat used in the experiment.
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Key Terms: Study Plant Population Frequency By Quadrat Method, Quadrat Method, Frequency, Plant Population, Species, Ecology, Sampling Units, Population, Percentage Frequency
What is Quadrat Method?
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The quadrat method is a technique that comes into the picture for measuring plant population frequency. In particular, a quadrat is defined as a sample plot that has a specific size and is used to study a specific population or a community.
- A major challenge comes when a huge bunch of species is needed in a desired amount of time.
- Quadrat method helps solve the problem by bringing a large of species to one place.
- Scientists use the quadrat method vividly.
- It can be rectangular, circular or irregular in shape.
- The method is useful for aquatic animals and slow-moving animals.
- The size of the quadrat depends upon the size of the population.
- Quadrat method is also useful in consumer-grade GPS systems.
Quadrat
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Frequency of Plant Population in Quadrat Method
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Frequency of plant population in quadrat method implies the number of times a plant has been repeated in a specified quadrat. It is measured by jotting down the presence of the specified species of plant that is under study.
- Frequency of plant population in quadrat method is solely based on the size and shape of a quadrat.
- It can be calculated by the following formula:
% Frequency = (Number of Sampling Units in which species occur) / (Total Number of Sampling Units Employed for the Study) * 100
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Experiment to study plant population in frequency by quadrat method
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In the given experiment, we will study plant population frequency by quadrat method.
Aim of the Experiment
The aim of the experiment is to study plant population frequency by quadrat method.
Study Plant Population Frequency by Quadrat Method
Materials Required
The material required for experiment to study plant population frequency by quadrat method are as follows:
- Thread
- Hammer
- Nails
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Real Lab Procedure
The procedure followed to study plant population frequency by quadrat method are as follows:
- Select an area of investigation with firm vegetation.
- Measure 1 m * 1 m dimensions and make a square using nails on the four sides.
- Tie the four sides of the nails with a thread and make a structure of a square.
- In the same manner, prepare nine more quadrats.
- Select a plant species for the study of plant population frequency.
- Select a species and name it X.
- Look for X species in all the ten quadrats and make it on a table.
- Similarly, search for species Y.
- Look out for it and mark it off the table, considering all the quadrats.
- Search for another species, Z, in all the ten quadrats and mark it on the observational table.
- Calculate the plant population frequency using the following formula.
Percentage Frequency = (Number of sampling units in which the species occurs) / (Total number of sampling units employed for the study) * 100
Observation for the experiment
The following table shows the observation of the plant population frequency by quadrat method.
| Plant Species | Quadrats employed in the study | Number of quadrats in which the species is present (N) | Percentage Frequency F=N/Q*100 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I | II | III | IV | V | VI | VII | VIII | IX | X | |||
| X | P | P | P | P | P | P | P | 7 | 70 % | |||
| Y | P | P | 2 | 20 % | ||||||||
| Z | P | 1 | 10 % | |||||||||
Conclusion
The plant population frequency is highest in species X with a frequency of 70 % and lowest in population Z with a frequency of 10 %.
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Things to Remember
- Study Plant Population Frequency By Quadrat Method is based on soil conditions and vegetative propagation.
- The process also depends upon the quantity and dispersal of seeds and predation by insects or diseases.
- Ecology is huge, and knowing about the population of a plant becomes difficult.
- Quadrat implies a specified area or plot from where a population of a species can be taken out.
- It can be of any shape, but all the quadrats must be of the same shape and size.
- The frequency of plant population is the number of times a species is repeated in a given quadrat.
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Sample Questions
Ques. What is a Quadrat? (3 marks)
Ans. Quadrat is a sample area where a population of a species or a community is calculated. It can be of any shape or size just one aspect is needed to be taken care of and all the quadrats must be equal.
- Quadrat can be in in the shape of rectangle, circle or any other irregular shape.
- It is useful for aquatic animals and slow-moving animals.
- The size of the quadrat depends upon the size of the population.
- The method is also useful in consumer-grade GPS systems.
Ques. What do you mean by frequency? (3 marks)
Ans.
Frequency is the number of times or occurrences of the specified aspect per unit time. It indicates the probability of finding a species in a given set of quadrats. Frequency is usually expressed in percentage.- It is also known as the frequency index.
- The method takes into account the record of species.
- It determines the difference between plant communities.
- It also detects a change in the composition of vegetation.
Ques. What is plant population frequency? (3 marks)
Ans. Plant population frequency is the number of times a species of plant is repeated in a specified quadrat. It describe distribution of plant species in a community. It is said to be proportional to the number of times plant appear in that quadrat.
- The plant population frequency depends upon the size of the plot.
- The presence of species is marked in the quadrant table.
- Frequency is sensitive to changes with respect to seedling establishment.
Ques. What is the formula of plant population frequency? (2 marks)
Ans. The formula of plant population frequency is -
Percentage Frequency = (Number of Sampling Units in which species occur) / (Total Number of Sampling Units Employed for the Study) * 100
Ques. If in a quadrat half of the species are present what will be the plant population frequency? (1 mark)
Ans. If in a quadrat half of the population is present the plant population frequency will be 50 %.
Ques. How one can say the plant population frequency is high and low? (2 marks)
Ans. When the number of times a species is repeated in a quadrat is greater than the others, then one can say the plant population frequency of that quadrat is high. When the number of times, means the frequency of a species of a quadrat is lowest than the rest, then one can say the plant population frequency is low f that quadrat.
Ques. How variation in frequency is caused? (3 marks)
Ans. The variation in frequency is caused due to various reasons like soil quality, soil conditions. Vegetation propagation, grazing, diseases, biotic activities, habitat of the area, topography, environmental conditions, atmospheric conditions, etc.
- The method cannot analyse whether the parameter of vegetation changes with change of frequency.
- It is affected by the seedling establishment.
- The process does not accurately determine the size of the quadrat.
- The identification skills is also not clear.
Ques. What is the aim of the experiment and what materials are used in the experiment? (2 marks)
Ans. The aim of the experiment is to study plant population frequency by quadrat method. The material required for experiment to study plant population frequency by quadrat method are as follows:
- Thread
- Hammer
- Nails
Ques. Explain population density? (3 marks)
Ans.
Population Density is defined as the measurement of the required population per unit area. In this process, the total population is divided by the total area. If population density is low, then the fertility level of the organism decreases.- Population density depends upon the natality and immigration.
- Both factors help increase the population density.
- It is also depends upon the mortality and emigration.
- Due to mortality and emigration, the population density is decreasing.
Ques. What are the advantages of the quadrat method? (3 marks)
Ans. The advantages of the quadrat method are as follows:
- The Quadrat method is a quite simple and inexpensive method.
- It uses cheap quality equipment but gives an accurate result.
- The method is suitable for studying plants and slow-moving and fast-moving animals.
- In this method, the researcher can work in the field without any fear and care.
Ques. What are the assumptions made using the quadrat method? (3 marks)
Ans. The assumptions taken in the quadrat method are as follows:
- The size of the quadrat must be known before the experiment.
- It is important to predetermine the number of individuals used in the experiment.
- The sample of the quadrant is equivalent to the area of study.
Ques. What is natality and mortality? (2 marks)
Ans. Natality is defined as addition or birth of new species in the existing population of organisms. Mortality on the other hand is defined as the removal or deadth of the existing members of the organism.
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