Changing Environments
Plants have adapted to their environments over millions of years, developing features that help them survive. But what happens when those environments change, and can plants adapt quickly enough to keep up?
Plants surviving change
If a plant is living in a particular environment, it can thrive if it has the right adaptations to survive in its environment. If the environment starts to change, the plant’s adaptations might not be suited to the changes in the environment.
Having lots of different types of plants growing in the environment is called ‘biodiversity’ and it is important for making sure there is plenty of food and shelter for native wildlife, including animals, birds, and insects.
There are many ways in which people have had an impact on the survival of plant species in our environment. Here are some examples of the human impact on plant survival.
Land clearing: People cut down trees and clear vegetation to make space for farms to grow food, to make space for houses to be built, and to make roads. They also cut down trees for wood.
Soil salinity: When people use too much water and cut down too many trees, the soil can become too salty. Some plants can survive in salty soil, but many cannot.
Invasive species: Plants that are not native to Australia can become weeds and compete with Australian native plants for space to grow.
Activities
Study the plants in the school grounds and plan for their survival
Working in pairs, students study an area of the school grounds and record the following information about the plants in that area:
How many different types of plants can you see?
Do the plants look healthy?
Are there any weeds that might prevent other plants from thriving?
What could be done to help the plants thrive in their location?
- If possible, find out who takes care of the garden and ask them questions about how they care for the garden and if there are any challenges in keeping the plants healthy.
- Hold a class discussion about improvements that could be made in the school playground to help the plants survive and thrive.
Investigate the effects of salt and sunlight on plant growth
Materials: Paper cups (1 per student), cotton wool balls (1 per student), fast-growing seeds (e.g. cress or alfalfa), table salt, jugs or bottles of water
Work in groups of three to conduct a fair test to see how salt and sunlight affect the growth of a plant seed.
- Day 1: Label the cups, ‘A’, ‘B’, and ‘C’.
- For each cup, wet a cotton wool ball until it is just moist and spread the cotton wool over the base of the cup.
- Sprinkle a few seeds on the cotton wool in each cup, adding the same number of seeds to each cup.
- Leave the cups inside, away from direct sunlight, for 2 days. Sprinkle a few drops of water on the seeds every day to keep the cotton wool moist.
- Day 3:
Place Cup A in a bright position (e.g. next to a window).
Place Cup B next to Cup A and add a small pinch of table salt to the cotton wool in Cup B.
Place Cup C in a dark cupboard.
- Each day, check the cups to make sure the cotton wool is moist, but not too wet.
- Observe how the seeds grow over a week or two. Each day, record observations using labelled diagrams and descriptions.
Have a class discussion to compare the results for each group:
Did all groups get similar results?
How could the experiment be improved?
What else could be tested in a similar experiment?
Image 1: Land Clearing Gulmarrad Northern Rivers Clarence Valley. Credit: John Turbill/DCCEEW 109804. Source: https://images.environment.nsw.gov.au /