1. Remind me to take the register!
Starter Activity
Get set go!
Three minutes
The sub-topic that we are about to start is called “Techniques to study organisms and the environment”.
Why do would anyone need to find out about an environment and the organisms living in it?
What factors might they need to measure and WHY?
Discuss this with your group. Listen carefully to what everyone has to say as you may be asked to put forward your group’s ideas.
Remind me to take the register!

2. Today we’re going to look at
What are we going to learn about today?
Today we’re going to look at
why we survey ecosystems.
definitions of biotic and abiotic factors.
measuring abiotic factors.

3. Why study an environment?
Ecosystems may be surveyed to gauge their health.
In general the more species found in an ecosystem (i.e. the higher its biodiversity) the healthier it is.
The presence or absence of particular species may indicate the presence of pollutants or other particular environmental conditions.
If land use change is proposed (e.g. housing or industry) then surveying is necessary to assess the possible effect of the change. This is called ENVIRONMENTAL IMPACT ASSESSMENT (EIA).

4. Biotic and Abiotic factors.
An ecosystem includes all the living things, (community ), their non-living surroundings (habitat) and the factors which affect their lives.
Biotic Factors.- Are factors in the ecosystem related to living things. e.g. competition for food, space, predation and disease.
Abiotic factors. - are non-living factors in the ecosystem e.g. pH, light,moisture temperature, flow rate etc.

5. Complete the card sort exercise. Check your answers with your teacher
And fill in the table in your notes.

6. Biotic factors Abiotic factors competition pH predation temperature
disease
oxygen concentration
Build up of toxic waste produced by the organism itself
humidity
grazing
soil moisture
wind speed
light intensity
heavy metal levels in soil
SUMMER, WINTER AND WEATHER ARE NOT ABIOTIC FACTORS! Low temperatures, high temperatures, rainfall etc. are! You can measure abiotic factors.

7. Measuring abiotic factors- Light.
Light intensity may be measured by using a light meter.
The units used to measure light intensity are lux.
Possible errors that might arise when using a light meter are
inadvertently shading the meter with your body.
not taking enough samples
REMEMBER ROAR
Repeat
Obtain
Average
Reliable

8. Sun plants Shade plants Why measure light intensity?
Plants need light for photosynthesis. They convert light energy to chemical energy in carbohydrates (food) that they need to grow. Plants that grow fast live in areas that have high light intensity. They are called “sun plants”. Plants that live in areas of lower light intensity, “shade plants”, grow more slowly but do survive.
Sun plants
Shade plants

9. Sun plant or shade plant?
Common daisy
Ivy
Sticky willy
White clover
Broad leaved plantain
Wood avens
Dandelion
Male fern
Stinging nettle
Creeping buttercup

10. Sun plants Shade plants Broad leaved plantain Ivy Common daisy
Stinging nettle
Dandelion
Wood avens
White clover
Sticky willy
Creeping buttercup
Male fern
These sun plants are found growing in short grass where they don’t have to compete for light. The shade plants are woodland plants and are normally shadowed by the leaves of trees.

11. Why measure light intensity?
Some animals favour light more than others.
What light intensities do you think are favoured by these two species and why?

12. ROAR Measuring abiotic factors- Soil moisture.
A moisture probe is used to measure soil water content.
Possible errors that might arise when using a moisture probe could be
Moisture left on probe from last sampling.
(solution wipe probe between tests)
not taking enough samples.
ROAR

13. Yellow flag iris and meadow sweet.
Why measure soil moisture?
Different plants need different levels of soil moisture.
Yellow flag iris and meadow sweet.
Rushes
Marsh marigold
Wet soils
Lady’s smock
Verbascum
Well drained soils
Hare bell
Ling heather
Sedum

14. ROAR Measuring abiotic factors- Soil pH.
A pH probe is used to measure soil pH (acidity or alkalinity).
Possible errors that might arise when using a pH probe could be
soil left on probe from last sampling.
(solution wipe probe between tests)
not taking enough samples.
ROAR

15. Rhododendron ponticum
Why measure soil pH?
Different organisms do best in different levels of soil pH.
Rock rose and thyme
Bee orchid
Sheep’s bit scabious
Land snails
alkaline soils
Ling heather
Sun dew
Butterwort
Rhododendron ponticum
Acid soils

16. ROAR Measuring abiotic factors-Temperature.
How would you measure temperature of a habitat?
A thermometer is used to measure temperature in oC.
Possible errors that might arise when using a thermometer are
placing it in direct sunlight
holding the bulb in your hand
not repeating the test.
ROAR

17. Why measure temperature?
Different organisms need different temperatures.

18. If there is anyone in your class that wasn’t at Valleyfield
take them onto the grass behind
science and show them how to use
a light meter and a moisture
meter and probe.

19. Ten minutes
Turn to page 9 of Standard Grade Biology and answer questions 1-3 in full sentences.

20. Learning Outcomes
Identify abiotic factors. (e.g. light, temperature, soil moisture, pH etc.)
Give details of the techniques which would be used to measure light intensity, soil moisture, soil pH and temperature.
Identify possible sources of error that might accompany each of these measurement techniques and explain how these may be minimised.

21. Homework-