Home

Biology

Biology practicals

Using field-work techniques

Select Lesson

Exam Board

Select an option

Biology practicals

Investigating specimens using microscopes

Investigating the effect of pH on amylase activity

Investigating osmosis in potatoes

Investigating limiting factors of photosynthesis

Investigating the rate of respiration

Using field-work techniques

Ecosystems and material cycles

Ecosystems, competition and environmental changes

Human impacts on biodiversity

Conservation and maintaining biodiversity

The carbon cycle

The water cycle

Obtaining potable water

The nitrogen cycle

Exchange and transport in animals

Specialised exchange surfaces

Human circulatory system

Aerobic and anaerobic respiration

Animal coordination, control and homeostasis

The human endocrine system

Hormones: adrenaline and thyroxine - Higher

Hormones in human reproduction

Treating infertility - Higher

Homeostasis and blood glucose

Plant structures and their functions

Photosynthesis and limiting factors

Factors limiting the rate of photosynthesis - Higher

Water and mineral transport in plants

Health, disease and the development of medicines

The relationship between health and disease

Communicable disease

Sexually transmitted infections

How the body fights disease

Vaccination, immunisation and medicines

Drug development and testing

Non-communicable diseases

Calculating BMI and the waist-to-hip ratio

Cardiovascular disease and treatment

Natural selection and genetic modification

Evolution by natural selection

Fossils as evidence for evolution

Classifying living organisms

Selective breeding

Uses and evaluation of genetic engineering

The process of genetic engineering - Higher

Genetics

Meiosis, sexual and asexual reproduction

DNA: structure, genes and chromosomes

Inheritance and genetic diagrams

Inherited disorders

Types and sources of variation

The human genome project

Cells and control

The cell cycle and stages of mitosis

Cell differentiation, stem cells and ethics

The nervous system and the reflex arc

Key concepts

Eukaryotic and prokaryotic cells

Specialised animal and plant cells

Types of microscopes and calculations

Enzymes

Transport systems in cells

Working scientifically

The scientific method

Science communication and ethics

Evaluating risks and hazards

Collecting data

Processing and presenting data

Units and equations

Structuring a scientific report and drawing conclusions

Uncertainties and evaluations

Practical skills

Measuring techniques

Safety and ethics

Designing experiments

Methods of heating substances

Working with electronics

Random sampling and sampling methods

Comparing results using percentage change

Explainer Video

Tutor: Jasmine

Summary

Using field-work techniques

In a nutshell

Quadrats are square frames that enclose a given area, they can be used to investigate the distribution of small organisms in an area. You can also investigate changes in distribution using lines called transects. Sampling along the length of a transect using a quadrat is known as a belt transect. You will first measure the population size of a common species in a habitat and then use sampling techniques to investigate the effect of an abiotic factor on the distribution.

Equations

You need to know this equation for these experiments.

$estimated\space population\space size ={{total\space area \over area\space sampled} \times total\space number\space of \space plant\space species\space counted }$

Equipment list

The following equipment can be used to investigate the distribution of small organisms in an area.

Equipment	Use
$1\space m^2$ Quadrats	To measure distribution in a given area.
$30\space m$ Tape measures	To measure your survey area.
Light meter	To measure light intensity.

Experiment 1: Estimating the population size of a chosen plant species in a given area using a quadrat

Experimental variables

Every experiment will have an independent, dependent and control variable. The independent variable is the variable that you change. The dependent variable is the variable which depends on the independent variable, therefore it is the one you measure. The control variable is the variable that is kept the same during the experiments.

Independent variable	$The \space sampling \space area.$
Dependent variable	$Number \space of \space your \space chosen \space plant \space species.$
Control variable	$The \space surveying \space area.$

Safety precautions

When performing experiments, it is important you consider safety precautions. However, in this experiment there are no significant risks.

Method

These are your instructions on how to complete the experiment.

Biology; Biology practicals; KS4 Year 10; Using field-work techniques — A quadrat.

1.	Using two tape measures, lay out a $10\space m \times 10\space m$ surveying area in your chosen habitat.
2.	Use a random number generator to generate a set of coordinates.
3.	Place the quadrat at this position.
4.	Count the number of your selected plant species in this area.
5.	Repeat steps 2-4 for $10$ different points in your surveying area.

Analysis

This is how you will use your data to form conclusions.

Use the formula to estimate population size of your chosen plant species in the surveying area:

$estimated\space population\space size ={{total\space area \over area\space sampled} \times total\space number\space of \space plant\space species\space counted }$

Conclusion

You can compare your estimated population size with your classmates to see how similar your results are.

Evaluation

If your results are very different compared to your classmates, it is important that you consider why. One common error may be miscounting the number of species in the quadrat, next time you may choose to count the species twice. You should identify any anomalous quadrat recordings and exclude them from your results.

Experiment 2: Investigating the effect of light intensity on the distribution of your chosen plant species using a transect line.

Experimental variables

Independent variables	$The\ sampling\ area\ and\ light\ intensity.$
Dependent variables	$Number\ of\ your\ chosen\ plant\ species.$
Control variable	$The\ surveying\ area.$

Safety precautions

When performing experiments, it is important you consider safety precautions. However, in this experiment there are no significant risks.

Method

These are your instructions on how to complete the experiments.

1.	Place the $30\space m$ tape measure in a line from the base of a tree to an open area of ground. This is the transect line.
2.	Put the quadrat at $0\space m$ and count the number of your chosen plant species.
3.	You should also record the light intensity using the light meter. *Note:* Abiotic factors are non-living factors, in this experiment light intensity is the abiotic factor.
4.	Repeat steps 2 and 3 every $5\space m$ along the transect line.
5.	Record your results in a suitable table.

Analysis

This is how you will use your data to inform conclusions.

1.	Plot a graph with appropriate scales. The dependent variable (number of plant species) should be on the $y$ -axis and the independent variable (light intensity) should be on the $x$ -axis. Draw a line of best fit, label your axes and add a suitable title. *Note*: Your line of best fit should past through the origin.
2.	Write a sentence explaining the relationship between the two variables as demonstrated by your graph.

Conclusions

Your graph should show a positive correlation between plant abundance and light intensity. This means as the light intensity increases, the abundance of plant species also increases. This makes sense as plants require light for photosynthesis which is the process they use to make food for growth.

Evaluation

If your results were unexpected, you must consider why. Ask yourself questions about your techniques and assess the equipment you used. You may need to edit the method or surveying area next time. One error may be misidentifying the plant species. This would lead to miscounting and inaccurate results.

Learn with Basics

Length:

Unit 1

Random sampling and sampling methods

Unit 2

Distribution and abundance of organisms

Jump Ahead

Optional

Unit 3

Using field-work techniques

Final Test

Create an account to complete the exercises

FAQs - Frequently Asked Questions

What is the dependent variable when using a belt transect?

The dependent variable when using a belt transect is the number of plant species.

What results would I expect when measuring plant species abundance and light intensity?

When measuring plant species abundance and light intensity, you should expect a positive correlation. This means as the light intensity increases, the abundance of plant species also increases.

What is a quadrat?

Quadrats are square frames that enclose a given area.

Home

Biology

Biology practicals

Using field-work techniques

Videos

Summary

Exercises

Select Lesson

Exam Board

Select an option

Biology practicals

Investigating specimens using microscopes

Investigating the effect of pH on amylase activity

Investigating osmosis in potatoes

Investigating limiting factors of photosynthesis

Investigating the rate of respiration

Using field-work techniques

Ecosystems and material cycles

Ecosystems, competition and environmental changes

Human impacts on biodiversity

Conservation and maintaining biodiversity

The carbon cycle

The water cycle

Obtaining potable water

The nitrogen cycle

Exchange and transport in animals

Specialised exchange surfaces

Human circulatory system

Aerobic and anaerobic respiration

Animal coordination, control and homeostasis

The human endocrine system

Hormones: adrenaline and thyroxine - Higher

Hormones in human reproduction

Treating infertility - Higher

Homeostasis and blood glucose

Plant structures and their functions

Photosynthesis and limiting factors

Factors limiting the rate of photosynthesis - Higher

Water and mineral transport in plants

Health, disease and the development of medicines

The relationship between health and disease

Communicable disease

Sexually transmitted infections

How the body fights disease

Vaccination, immunisation and medicines

Drug development and testing

Non-communicable diseases

Calculating BMI and the waist-to-hip ratio

Cardiovascular disease and treatment

Natural selection and genetic modification

Evolution by natural selection

Fossils as evidence for evolution

Classifying living organisms

Selective breeding

Uses and evaluation of genetic engineering

The process of genetic engineering - Higher

Genetics

Meiosis, sexual and asexual reproduction

DNA: structure, genes and chromosomes

Inheritance and genetic diagrams

Inherited disorders

Types and sources of variation

The human genome project

Cells and control

The cell cycle and stages of mitosis

Cell differentiation, stem cells and ethics

The nervous system and the reflex arc

Key concepts

Eukaryotic and prokaryotic cells

Specialised animal and plant cells

Types of microscopes and calculations

Enzymes

Transport systems in cells

Working scientifically

The scientific method

Science communication and ethics

Evaluating risks and hazards

Collecting data

Processing and presenting data

Units and equations

Structuring a scientific report and drawing conclusions

Uncertainties and evaluations

Practical skills

Measuring techniques

Safety and ethics

Designing experiments

Methods of heating substances

Working with electronics

Random sampling and sampling methods

Comparing results using percentage change

Explainer Video

Tutor: Jasmine

Summary

Using field-work techniques

In a nutshell

Equations

You need to know this equation for these experiments.

$estimated\space population\space size ={{total\space area \over area\space sampled} \times total\space number\space of \space plant\space species\space counted }$

Equipment list

The following equipment can be used to investigate the distribution of small organisms in an area.

Equipment	Use
$1\space m^2$ Quadrats	To measure distribution in a given area.
$30\space m$ Tape measures	To measure your survey area.
Light meter	To measure light intensity.

Experiment 1: Estimating the population size of a chosen plant species in a given area using a quadrat

Experimental variables

Independent variable	$The \space sampling \space area.$
Dependent variable	$Number \space of \space your \space chosen \space plant \space species.$
Control variable	$The \space surveying \space area.$

Safety precautions

When performing experiments, it is important you consider safety precautions. However, in this experiment there are no significant risks.

Method

These are your instructions on how to complete the experiment.

1.	Using two tape measures, lay out a $10\space m \times 10\space m$ surveying area in your chosen habitat.
2.	Use a random number generator to generate a set of coordinates.
3.	Place the quadrat at this position.
4.	Count the number of your selected plant species in this area.
5.	Repeat steps 2-4 for $10$ different points in your surveying area.

Analysis

This is how you will use your data to form conclusions.

Use the formula to estimate population size of your chosen plant species in the surveying area:

$estimated\space population\space size ={{total\space area \over area\space sampled} \times total\space number\space of \space plant\space species\space counted }$

Conclusion

You can compare your estimated population size with your classmates to see how similar your results are.

Evaluation

Experiment 2: Investigating the effect of light intensity on the distribution of your chosen plant species using a transect line.

Experimental variables

Independent variables	$The\ sampling\ area\ and\ light\ intensity.$
Dependent variables	$Number\ of\ your\ chosen\ plant\ species.$
Control variable	$The\ surveying\ area.$

Safety precautions

When performing experiments, it is important you consider safety precautions. However, in this experiment there are no significant risks.

Method

These are your instructions on how to complete the experiments.

1.	Place the $30\space m$ tape measure in a line from the base of a tree to an open area of ground. This is the transect line.
2.	Put the quadrat at $0\space m$ and count the number of your chosen plant species.
3.	You should also record the light intensity using the light meter. *Note:* Abiotic factors are non-living factors, in this experiment light intensity is the abiotic factor.
4.	Repeat steps 2 and 3 every $5\space m$ along the transect line.
5.	Record your results in a suitable table.

Analysis

This is how you will use your data to inform conclusions.

1.	Plot a graph with appropriate scales. The dependent variable (number of plant species) should be on the $y$ -axis and the independent variable (light intensity) should be on the $x$ -axis. Draw a line of best fit, label your axes and add a suitable title. *Note*: Your line of best fit should past through the origin.
2.	Write a sentence explaining the relationship between the two variables as demonstrated by your graph.

Conclusions

Evaluation

Learn with Basics

Length:

Unit 1

Random sampling and sampling methods

Unit 2

Distribution and abundance of organisms

Jump Ahead

Optional

Unit 3

Using field-work techniques

Final Test

Create an account to complete the exercises

FAQs - Frequently Asked Questions

What is the dependent variable when using a belt transect?

The dependent variable when using a belt transect is the number of plant species.

What results would I expect when measuring plant species abundance and light intensity?

When measuring plant species abundance and light intensity, you should expect a positive correlation. This means as the light intensity increases, the abundance of plant species also increases.

What is a quadrat?

Quadrats are square frames that enclose a given area.