The grade 9 biologists have started studying the final grade 9 biology topic on ecosystems and human influences. To model the flow of energy through food chains we roleplayed the transfer of water (energy) from a large bowl (the sun) to a number of cups with holes in them (trophic levels) to find out how much water (energy) passed to the end of the chain. We then evaluated how the roleplay was similar to. energy loss (loss of water) through food chains and how it could be improved (including the role of decomposers). The students left the lesson with a better understanding of the fundamental concept of how not all energy is passed on to the next trophic level and hence why there is a limit to the maximum number of trophic levels in a food chain.
The grade 11 HL students have been studying the role of the kidney in osmoregulation. In this lesson we discussed the role of antidiretic hormone (ADH) in fine tuning the final volume and concentration of the urine. We also looked at a number of urine samples and tried to match them to potential diseases ( diabetes, kidney damage) and states of hydration.
In IBDP Biology the students have to be able to plan experiments that measure the rate of photosynthesis.The students cut leaf discs from a plant and transferred them to a syringe filled with water. Once all the air was removed the leaf discs sunk to the bottom of the syringe. As the leaf discs carried out photosynthesis, they produced oxygen that moves into the air spsces surrounding the spongy mesophyll. The leaf discs will then rise as oxygen is produced. By measuring how long it takes for the leaf discs to rise; the rate of photosynthesis can be measured.
This week in coordinated science, we used every day lab apparatus to model the digestive process. The apparatus above was used to show the journey of an unbalanced breakfast of crisps, peanuts, bread, milk and coffee. Can you match the apparatus with part of the alimentary canal in this photo? Cam you spot the end product of digestion after egestion from the anus?
This week in Coordinated Science (Biology) we are approaching the end of our first unit on cells, cell processes and animal digestion. To model how our digestive system works we used every day household objects to show what happens in each region of the alimentary canal. The students took on the roles of the teeth using pestle and mortar to crush food), the oesophagus (pushing food along a tube to show peristalsis), the stomach (churning food in a plastic ziplock bag), and the intestines (modelling absorption of food through woman’s tights and the absorption of water with paper towels). They enjoyed witnessing for themselves the final product of the model digestive system!
I hope you enjoyed the dissection today and I’m impressed that none of you had to leave the lab at any point!
Go to this website to investigate the factors which effect photosynthesis
I hope you found today’s first new Double Helix Club memorable even if it didn’t go as planned. We will complete the dissection at a later date.
To do an virtual frog dissection, check here http://www.surgery-games.org/43/Dissect-a-Frog.html
To find out more about frogs and frog dissections, check this glog http://tehescmarts.edu.glogster.com/frog-dissection/
I hope you enjoyed today and this years final Double Helix Club. I’m sorry you did not manage to do the Elephant toothpaste activity for yourselves.