This is ‘The Story of H’, by Lubomir Panayotov, and it recently won Best Storytelling in the Slideshare, ‘Tell a story in 30 slides or less’ contest. Helicobacter pylori is a bacteria that affects 50% of the population and has been shown to cause stomach ulcers. Australian scientists won the Nobel prize in 2005 for their discovery of this bacteria and it’s role in gastritis and peptic ulcer disease.
Source: Biology Online
This Wednesday afternoon we will be dissecting laboratory rats, which are specially bred for scientific purposes. This practical exercise is optional, but an excellent way to gain scientific skills of careful observation, identification of body parts and an understanding of the structure and function of the digestive system of mammals. If you plan to continue your science education at university, you will find this a valuable introduction to laboratory dissections. Make sure you read the practical instructions thoroughly, work slowly and carefully and document your progress with video or a digital camera. Remember that ‘dissection’ does not mean ‘to cut up’, it means ‘to expose to view’ – once something has been cut, it can’t be undone, so know what organ or tissue you are cutting and why.
Rat Dissection – Part 1: Exposing the Abdomen
Rat Dissection – Part 2: The Digestive System (Warning – graphic images)
Rat Dissection – Part 3: Identifying the organs of digestion.
What did you learn about dissection and the digestive system of a mammal? Compared to the length of the rat, how long was it’s alimentary canal? What was the difference in the wall of the stomach and the small intestine? What did you notice about the contents of the alimentary canal as they moved towards the rectum? What surprised you most about the inside of a rat?
Procedure for rat dissection.
Classification of the rat and glossary of terms (dorsal, ventral, thoracic etc.)
Check out Miss Baker’s Biology Blog, “Extreme Biology” for a video of a dogfish shark dissection.
Swedish scientists have used radioactive carbon-14 to show that between 0.5 and 1.0% of heart cells regenerate each year, depending on age. Read more here.
We were talking about bees in class during the last week of term – I happened upon this interesting article from the Scientific American – “Plan Bee: As Honeybees Die Out, Will Other Species Take Their Place?”
I’ve also added a few more resources to the Free Stuff! column on the RHS – Check out “Biology Q and A” for over 1800 questions and answers about Biology.
No, it’s not a stawberry cocktail! Did you know that you can extract DNA using simple kitchen equipment and readily available materials? The CSIRO has some great biology experiments, including this one to extract DNA from onions. You could also use kiwi fruit, dried peas, banana, liver or strawberries.
You can see the fine, white strands of DNA on the toothpick. During mitosis, these strands condense and become more visible in the cell (especially when a stain is used like in the image below). The amount of chromatin (DNA or nuclear material) varies between species.