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Carry out a practical investigation in a biological context, with guidance
Credits: 4 Assessed: Internally Lit/ Num Standard: Numeracy/ Literacy
Introduction
The standard requires conducting a practical investigation within a biological context, specifically within the scope of Level 8 in the Biology curriculum. This investigation is undertaken under the guidance of a teacher, where you take the lead in generating ideas, designing the investigation, and conducting the research. Throughout the process, the teacher offers support by
establishing parameters such as appropriate organisms, contexts, and equipment.
Provide general information on resources, potential directions, or adjustments for the investigation.
You need to:
plan and carry out the investigation.
determine the independent and dependent variables.
determine the control variable.
set quantities.
collect, process, and analyze data.
include data from other sources when drawing conclusions and writing a discussion.
present a scientific report on your findings.
You need to maintain a comprehensive logbook documenting your investigative process. Ensure that it includes dates, times, and records pertinent to the research on the organism's niche, exploration ideas, required equipment, the nature of collected data, the independent variable, the dependent variable, the number of trials conducted, raw data, and any other relevant details. The logbook serves as a crucial tool to validate the authenticity of your investigation. Regular checks of the logbook will be conducted, and feedback will be provided by your Learning Leader.
A Suitable Investigation
The most important part of the process is the selection of a suitable investigation, encompassing the following key aspects:
Choosing an appropriate organism (plant or other).
Selecting a doable investigation in relation to the available resources.
Designing an experiment aligned with Level 8 of the Biology Curriculum. A common obstacle to not achieving AS 91601 (Biology 3.1) is the simplicity of the investigation, falling short of the Level 8 standard. It is compulsory to incorporate a minimum of four values for the independent variable.
The investigation should be within the context of Level 8 Biology, covering areas such as animal behavior, plant and animal responses, ecological niche, aspects of biotechnology or genetic manipulation, modeling an evolutionary pattern, or homeostatic feedback.
Designing the investigation involves creating a fair test, pattern-seeking, or modeling activity to ensure its integrity and alignment with the learning objectives.
NOTE: NOT SUITABLE EXPERIMENTS
The examination of rocky shore distribution is deemed unsuitable as it corresponds to a Level 2 investigation.
Investigating whether slaters exhibit a preference for light or dark conditions is deemed inappropriate due to the necessity for a broader range of conditions.
An inquiry into the growth rate of specific plants in varied substrates, especially those divergent from their natural habitat, is irrelevant to the ecological niche and thus not considered suitable.
Conducting a study on plant growth in different fertilizers or substrates is not appropriate, as such investigations tend to be overly simplistic in nature.
ANIMAL ETHICS
An animal is classified under the Animal Welfare Act ( 1999) for animal ethics as "horses, cattle, sheep, goats, any bird, any marine mammal collected from on or vicinity of the seashore or any vertebrate animal kept in captivity and dependent upon humans for its care and sustenance."
Before experimentally manipulating any animal, it is imperative to seek approval from the Animal Ethics Committee to ensure that no creature is subjected to unnecessary cruelty, pain, or distress. It is advisable to steer clear of using animals that fall under the purview of ethics approval.
Even in the case of utilizing lowly invertebrate animals like blowflies, slaters, and daphnia, it is essential to recognize that these animals are not volunteers. They serve a biological purpose, and therefore, the utmost care and consideration are warranted in their treatment and handling.
Ecological Niche
The investigation involves aspects of the behavior and responses exhibited by animals or plants in relation to their external environment. The environmental factors influencing these responses include:
Abiotic factors such as temperature, light intensity, photoperiod, nutrient levels, concentration of CO2, humidity, exposure, aspect, soil, and substrate.
Biotic factors, which involve the presence of other organisms, such as competitors, predators, and herbivores.
Responses made to environmental factors that may be suitable for investigations include taxes and kineses in animals and tropisms and nastic responses in plants. Any investigations into aspects of animal and plant responses is likely to be in relation to the organism's niche. Therefore prior research into the niche of the chosen organism will be necessary to enable valid conclusions to be drawn and an in-depth discussion of the relevant biological concepts made.
Aspects of the ecological niche that should be focused on include:
the usual habitat of the organism and what the organism gains from this habitat.
adaptations of the organism that allow it to exploit its ecological niche.
important relationships the organism has with others such as feeding, predation, and competition.
Planning an Investigation
Statement of purpose
Decide on the purpose of the investigation and write a hypothesis. The hypothesis is an intelligent guess and is based on prior observation and research findings.
The hypothesis must be very specific and be based on both the dependent and the independent variables. Writing the hypothesis includes the scientific name of the organism being investigated as well as the common name for eg " That increasing the .............( insert the independent variable and range) will.......( do what to ?) the ..............( insert the dependent variable) due to.........( research the scientific theory or biological idea behind it).
For example:
" increasing the temperature from 0 to 30 degrees Celsius ( the independent variable and range) will increase the rate of movement (dependent variable) of slaters, Porcellio scaber because they are prone to desiccation (extreme dryness) and seek out moist environments to survive.
Method
The method is designed to collect data that will determine whether the hypothesis is correct or not. If the data collected does not allow you to determine this, then your method needs to be modified and the investigation repeated.
For a Fair Test
the independent variable must be specified and it must have a range of at least four values.
the dependent variable and how it is measured must be specified
how other key variables were controlled must be described. If these are not controlled then it is not a fair test.
The method must be valid - this means that the method outlines how to measure and record data so that a valid conclusion may be made from the results. This requires:
the range for the independent variable must be valid and quantified
the dependent variable has been measured in a valid way.
the method also needs to describe how sufficient data for the dependent variable to establish a trend.
all other variables that, may affect the outcome of the investigation have been controlled or taken into account.
The method must be reliable. This means it can be repeated and the same or similar results can be obtained. Measurements are typically repeated three times.
FINAL METHOD is a step by step description stating exactly how the investigation was carried out and it will go in the report you hand in for your assessment.
Collecting, recording and processing data
Raw data
The data you measure or collect is raw data. Record it in a spreadsheet. You must collect sufficient data so that any trend or pattern will be displayed. Therefore you need to ensure that you have a suitable range for the independent variable and make repeat recordings for each value of the independent variable.
Data collected must be relevant to the purpose of the investigation.
Data must be recorded in tables which include:
a full title that includes descriptions of the independent and dependent variables.
full headings and appropriate units for each column and row.
ruled lines around sets of data.
the data is ordered in a logical way.
raw and processed data being clearly distinguishable from each other.
https://www.pomona.edu/sites/default/files/bio40-lab.jpg
The raw data collected needs to be processed so that any trend can be shown to exist or not exist. Processing data involves calculations and graphing.
Processing data - Calculations
The data should be initially processed into the form stated in the hypothesis eg the density, rate., speed, percentage, frequency and so on. The correct number of significant figures needs to be used.
Data can be processed further to show the mean ( the average, x̄), median ( the middle value), and standard deviation ( the spread or variability of the data, S). These descriptive statistics give you information about the distribution of the data.
Processing data - Graphing
An accurately drawn graph speaks a thousand words.
Line Graphs: drawn for continuous data that have been obtained from an investigation into how the manipulation of one factor affects another. ( eg. how temperature affects the heart rate of daphnia). Outliers are ignored, the rest of the points are joined and/or a line of best fit is drawn.
Scatter graphs: drawn to show trends between two variables that correlate ( vary predictably), But there is no manipulation of one of the variables. ( eg relationship between body length and the number of eggs released in snapper).
Accurately drawn graphs have the full features:
a full title that includes descriptions of the independent and dependent variables ( best written as "The effect of [independent variable] on [dependent variable]............."
descriptive labels and correct units on each axis: the axes have been drawn using a ruler( if paper based)
appropriate and even increments ( ie a scale) for each value on each axis.
clearly and accurately plotted data.
neatly drawn lines joining the data, or line of best fit.
Interpreting data
Interpreting a graph means describing the patterns/ trends seen in on graph. This is done by talking about how the dependent variable changes as the independent variable changes. It is important to be very accurate when interpreting a graph. Refer to the scientific data from the graph and ensure you describe the trend or pattern over the entire graph.
It is this interpretation that will form the basis of your conclusion.
In the graph of the effect of temperature on the heartbeat of Daphnia it would be incorrect to interpret the graph as " As temperature increases, the heartbeat rate of Daphnia also increases" because this is both inaccurate and unspecific. A correct interpretation would be " As the temperature was increased to around 30 degrees Celsius, the heartbeat of daphnia also increased steadily from around 25 beats/min to 200 beats/min. However, above this temperature, the heartbeat rate dropped rapidly so that at 35 degrees Celsius, it was only around 50 beats/min. This interpretation uses specific data from the graph and refers to all the changes that occurred to the daphnia heartbeat.
Conclusion
The conclusion is a statement about the results of the investigation. A valid conclusion follows on from a valid investigation.
A valid conclusion must be based on the processed data. This means that the data must be specifically and accurately referred to. In the investigation into the effect of water temperature on the heartbeat of Daphnia, it is not sufficient to say " As the temperature of the water increased, the heartbeat of the daphnia also increased." Firstly this is not accurate and the conclusion is not valid: the heartbeat did increase but peaked and then started to decrease. Secondly, the actual processed data has not been referred to.
A valid conclusion must relate to the purpose of the investigation. Both the dependent variables and independent variables need to be referred to. So a valid conclusion could be " the heartbeat of daphnia increased gradually to a peak average heartbeat of 200 beats/min at 30 degrees Celsius, then decreased rapidly to 50 beats/min at 35 degrees Celsius.
Discussion
A discussion explaining the biological ideas related to the investigation is needed. the discussion not only explains the processed data from the investigation, but must include data/findings from other sources. The data or findings may be from past or present investigations by students or from outside sources ie published universities. Scientific principles may also form part of the findings.
In the discussion, you need to do more than just describe or reiterate the results. You will discuss how the results are significant in terms of the biology of the organism investigated and you must support your discussion with the knowledge and findings of others.
Evaluation
In an evaluation you justify the choices made in planning and carrying out the investigation. These choices relate to the following:
was the method valid?( Did the method allow you to measure what you wanted to measure, was the method a fair test? Were all the variables controlled so they did not influence or bias the results?)
were the results reliable? ( were sufficient data generated by large numbers of measurements from using a large number of organisms and or repeat recordings) to allow a trend ( or its absence) to be identified? would a repeat of the investigation produce a similar trend?
The evaluation is not a description of what went wrong or what you could have done better or what you could improve on if you did the investigation again
Resources
NZQA Achievement Standard Document
https://www.nzqa.govt.nz/nqfdocs/ncea-resource/achievements/2019/as91601.pdf
NZQA Achievement Standard exemplars
https://www2.nzqa.govt.nz/ncea/subjects/past-exams-and-exemplars/biology/as-91601/
as91601.pdf91601-Exemplar-.pdf
10/05/22
Students identify a experiment and write a aim and hypothesis (dependent and independent variables, no control variable)
Complete pages 8 and 9 of SciPad
Complete pages 10 and 11 of SciPad
7/05/22
Go over again and discuss on the structure of a scientific report and what to do in each section
Aim/Purpose > Hypothesis > Material > Method > Results > Conclusion > Discussion > Evaluation
Discussion about the Biotechnology Assessment ---> different parts to focus on, look at the marking criteria.
6/05/22
Complete page 6 of SciPad (Key terms). Discussion of the key terms
Discussion on the structure of a scientific report and what to do in each section
Aim/Purpose > Hypothesis > Material > Method > Results > Conclusion > Discussion > Evaluation
3/05/22
Discussion on the assessment and when its due
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