Biology is not about memorising words. It is about seeing how the parts make the whole work.The GOAT Notes™
Science is a way of finding out: observe, ask, test, measure, then infer from evidence. Knowledge is open to challenge and is revised when new evidence appears. Peer review means other scientists check the method before the findings are trusted. Life Sciences studies living things from molecules to biomes, and always asks how structure fits function, how organisms keep conditions steady (homeostasis) and how size affects surface area to volume.
The independent variable is what you change; the dependent variable is what you measure. Constants stay equal. A control is the setup without the change, used for comparison.
Line graph: change over time or a continuous variable. Bar graph: separate categories. Histogram: continuous data in groups, bars touching. Pie chart: parts of a whole.
Quote the unit with every value read off.
| Transport | Learners | % | Angle |
|---|---|---|---|
| Walk | 90 | 45 | 162° |
| Taxi | 60 | 30 | 108° |
| Bus | 30 | 15 | 54° |
| Car | 20 | 10 | 36° |
Average = sum of values ÷ number of values. Percentage = part ÷ whole × 100. Percentage change = change ÷ original × 100.
Divide by the original (12), not the new value.
A transverse section cuts across the structure; a longitudinal section cuts along its length. Draw in pencil, with clear single lines, no shading, and label lines that do not cross.
Magnification = drawing size ÷ actual size. Convert to the same unit first: 1 mm = 1000 µm.
Show the unit conversion; it earns the mark.
What does peer review mean in science?
Which statement is an inference rather than an observation?
Why do scientists change an explanation that was accepted for many years?
Which sentence best describes scientific knowledge?
Doctors once believed that stomach ulcers were caused only by stress. Later evidence showed that a bacterium is involved, and treatment changed. What does this show about science?
A learner studies how light intensity affects the height of bean seedlings after ten days. What is the independent variable?
A learner tests how water temperature affects the time a sugar cube takes to dissolve. What is the dependent variable?
In a test of how the mass of fertiliser affects maize growth, which is a properly named constant?
Which setup is the correct control for an investigation into a plant hormone sprayed onto cuttings?
Sipho tests the effect of sunlight on plant growth. Plant A is in full sun with 100 mL of water daily, plant B in shade with 200 mL daily, and plant C in a dark cupboard with 50 mL daily. What is the main flaw?
When is an investigation called reliable?
Which change makes an investigation more reliable?
When is an investigation called valid?
Group A measures the resting pulse of 3 learners once. Group B measures 30 learners three times each. Which group's results are more reliable, and why?
Lerato compares fertiliser X on maize in sandy soil with fertiliser Y on maize in clay soil. She uses 10 plants per group and repeats it 3 times, and her results agree each time. Which conclusion is correct?
Which graph is best for showing how the mass of a plant changes over 14 days?
Which graph is best for comparing the mean mass of four different bird species?
Which description matches a histogram?
A learner measures the length of 100 leaves and sorts them into groups: 0–9 mm, 10–19 mm, 20–29 mm and so on. Which graph should be drawn?
A learner draws a line graph of the number of learners who walk, take a taxi, take a bus or come by car. Evaluate the choice.
How is percentage change calculated?
The masses of five bean seedlings are 8 g, 11 g, 9 g, 14 g and 8 g. What is the mean mass?
A school has 200 learners. 25 of them cycle to school. What angle represents cycling on a pie chart?
A pond has 80 frogs in March and 60 frogs in June. What is the percentage decrease?
The mean height of a group of seedlings is 14 mm at the start and 21 mm at the end. What is the percentage increase in the mean?
What is a transverse section?
Which is a rule for a good biological drawing?
A drawing of a cell is 60 mm long. The actual cell is 0,06 mm long. What is the magnification?
A drawing is 45 mm long at a magnification of ×900. What is the actual length in µm?
In a drawing, a scale line 30 mm long stands for 15 µm. A cell in the same drawing is 60 mm long. What is the actual length of the cell?
A learner has the table below. Describe how to draw a line graph of these data. (6)
Table: Mean number of leaves on bean plants. Week 0: 2; week 1: 4; week 2: 7; week 3: 9; week 4: 12.
Give the graph a caption that names both variables, such as the mean number of leaves on bean plants over four weeks. Draw a line graph, because the data show change over time. Put time on the x-axis and the mean number of leaves on the y-axis, and label each axis. Write the units in brackets, weeks and number of leaves. Use an even scale on each axis, starting at zero, such as 2 leaves per block. Plot each point accurately, then join the points with a ruler or a smooth line.
Thabo investigates how the temperature of the water affects how quickly yeast makes bubbles of gas in sugar solution. Explain how he should plan the investigation so that it is valid and reliable. (5)
He should change only one thing, the water temperature, for example 10, 20, 30 and 40 °C. He measures the number of bubbles made in two minutes at each temperature. He keeps the mass of yeast, the volume of sugar solution and the amount of sugar the same in every flask. He repeats each temperature at least three times so that the results are reliable. He calculates the mean of the repeats and compares it with a control kept at room temperature.
A learner draws an onion cell in a drawing that is 40 mm long. The scale line is 10 mm long and stands for 50 µm. Calculate the magnification and the actual length of the cell in µm. Show your working. (4)
First convert to the same unit: 50 µm = 0,05 mm. Magnification = drawing size ÷ actual size = 10 ÷ 0,05 = ×200. Actual length of the cell = 40 mm ÷ 200 = 0,2 mm. 0,2 mm × 1000 = 200 µm.
Explain to a Grade 8 learner what makes an investigation a fair test, and why scientists repeat it.
Explain to a Grade 8 learner how to choose between a line graph, a bar graph, a histogram and a pie chart.
Explain to a Grade 8 learner why scientists sometimes change their minds, and why that is a strength.
This is a free preview of Topic 1. The full guide has every topic, the self-marking quizzes, mock exams, planner, journal and wellbeing tools.
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Exam stress is completely normal. Here are a few things that actually work. None of this replaces a doctor or a trusted adult.
Box breathing: 4 counts in, 4 hold, 4 out, 4 hold. Do it four times.
Look at the worked example below first, then make your own. Tick off each topic as you finish it.
Example (already filled in)
| Date | Subject | Topic | Done |
|---|---|---|---|
| Mon 8 Jul | Life Sciences | Your weakest topic, notes + summary | ✓ |
| Tue 9 Jul | Life Sciences | Next topic + 10 practice questions | ✓ |
| Wed 10 Jul | Life Sciences | A full past paper under time | – |
| Thu 11 Jul | Life Sciences | Mark the paper, revise weak spots | – |
Your plan
| Date | Subject | Topic | Done |
|---|---|---|---|
Your plan is saved only on this device. Use "Export plan" to keep a copy.
Every diagram you can label and every graph you can draw is a mark you have already banked. Go and collect them.