Resource 1: Looking at plants
Background information / subject knowledge for teacher
About the plant groups
Algae
What are they?
- They are the Earth’s simplest plants.
- They all have green chlorophyll, so they can use sunlight, water and carbon dioxide to make their own food.
- There are more than 25,000 different kinds of algae.
Where do we find them?
- Microscopic algae live in almost all natural water, especially the top 75 metres of the ocean.
- Algae are found in all wet places on Earth:
- - in fresh water, like streams, lakes and rivers,
- - in sea water – at the bottom of the sea and at the water’s edge,
- - in snow on mountain tops and in polar regions,
- - in hot springs,
- - near leaking taps and on damp walls.
What do they look like?
- Some are single-celled and can only be seen with a microscope.
- Some live together in colonies.
- Some are joined together to make large seaweed plants.
Why are they important?
- Algae are the primary source of food for all marine animals.
- They produce about 50% of all the earth’s oxygen through photosynthesis.
- They are used as good, fodder and fertiliser.
- We get chemicals from them which we use in medicine and industry.
Mosses
What are they?
- Mosses are very small green plants which are about 65 million years old.
- The fossil remains of mosses look very similar to the mosses we find today.
- There are more than 20,000 different kinds of mosses.
Where do we find them?
- Mosses grow in places that are damp for long periods. We find them:
- - on damp rocks
- - on frost floors
- - near drainpipes, drains and gutters
- - on the ground shaded by other plants
Why are they important?
Mosses have been used for a variety of interesting purposes:
- Native Americans used to grind up dried moss into a paste which they used to treat burns.
- In Europe, people allowed certain kinds of mosses to grow on roofs to make the roofs watertight.
- Germans discovered in the 1880s that dry moss pads made excellent absorbent bandages. Disinfected moss bandages were used to treat wounded soldiers in World War 1.
- Mosses are sometimes used as packaging for vegetables.
- Mosses are sometimes mixed in with soil to improve the soil’s water-holding capacity.
- Old compressed moss is used for fuel in the form of a coal called peat.
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| Dense moss colonies in a cool coastal forest | Three mosses on a tree |
Original source for image: www.wikipedia.org
Ferns
What are they?
- Most ferns are small plants growing no more than a metre high.
- There are some ferns that grow as high as a small tree and are woody (tree ferns).
- All ferns have veins and vessels for conducting water, mineral salts and food.
- At one time in Earth’s history, terns were the most dominant type of plant.
- There are more than 10,000 different kinds of ferns.
Where do we find them?
- Ferns are land plants but they need water for reproduction.
- They grow in cool, moist, shady places, like the floor of tropical rain forests and on the banks of rivers and streams.
- They also grow in places that get lots of water at certain times of the year.
What do they look like?
- The individual leaves of a fern together make up fronds.On the back of the fronds dots of brown sori are found. Sori contain spores which are used in reproduction.
- The tip of a frond unrolls like a spring as the frond grows.
Why are they important?
Ferns were the dominant plants on Earth 300 million years ago. At that time Earth’s climate was warm and rainy and the land was covered by shallow seas and swamps. The ferns grew throughout the year but as they had shallow roots many ferns toppled over into the swamps. Here they rotted slowly. Eventually, over a long period of time, they became covered with rock. Over millions of years they turned into coal and oil, which we use today for fuel and other purposes.
3. Focus on local plants
