Sour Figs and food chains

would you taste these white powders?

………… do you know what these two substances are and how they are connected?

glucose and starch
glucose and starch
Tasting was the first thing Gr 6 and 7 teachers were asked to do at the NST workshop at the Edith Stephens Nature Reserve, in Phillipi run by the Primary Science Programme (PSP)  in Feb 2017.
PSP offers CAPS  in-service teacher training courses and have a range of excellent materials for sale.
  • Glucose is sweet and soluble in water.
  • Starch is not sweet and is insoluble in water.
  • Glucose molecules can be joined together to make long chain molecules of starch

 

 

 

tasting glucose
tasting glucose

 

Plants have the amazing ability to harness light energy from the sun and convert water and carbon dioxide into glucose molecules.
Photosynthesis takes place constantly, quietly and efficiently in every green part of plants.
Soluble glucose is transported to different parts of the plant (roots, stems, leaves, fruits and seeds) where it is transformed into insoluble starch  for safe storing.
Where would we get our food if plants did not do this?
The only waste product of this reaction is oxygen

 

                sunlight + carbon dioxide + water ————-> glucose + oxygen

 

Teachers consolidating their understanding of photosynthesis

 

Discussing the process of photosynthesis
Discussing the process of photosynthesis

 

What do sour figs and photosynthesis have in common?

Looking at the flower of the Sour fig plant
Looking at the flower of the Sour fig plant

 

Sour fig plants grow in the sandy soil of the Cape Flats. The leaves are succulent and green and make glucose sugar and starch.
Flowers invite pollinators to drink sweet nectar and in the process transfer pollen between flowers. This is important for reproduction.
The Sour Fig fruits that are produced after pollination are good to eat. A variety of animals like to eat them.

The sour Fig becomes the beginning link in the food chain

 

Looking at the Sour Fig plant growing in the sandy ground outside
Looking at the Sour Fig plant growing in the sandy ground outside
The leaves are not very tasty and we struggled to find any evidence of leaves being chewed.
Flowers had a variety of pollinators visiting : bees, beetles and butterflies.
We didn’t see the fruits but we know baboons, tortoises and humans love to eat them

 

 

 

Constructing a food chain based on the Sour Fig plant

Constructing a food chain based on the Sour Fig plant
Constructing a food chain based on the Sour Fig plant

 

Each group of teachers constructed a different food chain based on the animal cards that they had.

 

The challenge was then to join all the food chains together and construct a web of animals all connected to the Sour Fig.
Teachers found this an interesting and challenging exercise to do. Sour Figs grow on the Cape Flats so they felt that they can do this activity in the classroom

 

 

Animals connected to the Sour Fig

Food webs are just interconnected food chains
Food webs are just interconnected food chains

 

A set of animal cards can be purchased from PSP. https://www.psp.org.za/about/

 

Teachers comments

  • I enjoyed the interactive photosynthesis lessons. They were really well presented and it makes me want to teach NST/NS It is interesting how much we know and don’t realise. Estelle Wheeler Gr 7 Attwood
  • The two sessions really taught me skills to prepare and present my lesson in class. I got information that I did not know about before Mr M Xakata Sivile Gr 6 NST

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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