Image Source - The United Kingdom 10 pound note.
This year many scientists are celebrating Charles Darwin’s 200th birthday. Darwin is famous for his book, “The Origin of Species” which was a revolution in biology and controversial in it’s day for the theory that species could evolve over generations to form new species – and that humans had evolved from an ape-like ancestor! Darwin was the first scientist to propose this theory and provide a simple mechanism – survival of the ‘fittest’ – that could explain how it works. Even before chromosomes and genetics had been discovered, he proposed that there was some ‘hereditary factor’ that was passed through generations and conferred characteristics that made individual organisms more or less likely to survive, breed and pass on those characteristics to their offspring.
Catalyst is celebrating Darwin’s 200th birthday with a special edition, that includes interviews with famous scientists, articles about DNA and missing fossil links and archives of related stories. Read a biography of Charles Darwin from the BBC and find out more at “Darwin – the Genius of Evolution“.
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.
Today we discussed the digestive systems of other animals, including flatworms, earthworms, cockroaches and birds. How is the diet, size and structure of the animal related to their digestive systems? What is the function of a ‘gizzard’ and ‘crop’ in earthworms and birds?
Today we are looking at the different digestive systems of mammals and investigating the relationship between diet, nutritional requirements and the structure and function of digestive systems. You will learn the meaning of the terms fermentation, hind-gut and fore-gut fermenters, ruminants, caecum and colon.
Check out the MyStudiyo Quiz “Heterotrophs are Consumers” at http://www.mystudiyo.com/ch/a86690/go
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.
“The first high-resolution close-up photographs of the H5N1 avian flu virus, taken by science photographer Lennart Nilsson, appeared in the Swedish daily Dagens Nyeter (DN) on November 7, 2005, in what the newspaper said was a world exclusive.”
Try these fun activities from Quia to revise Unit 1: Area of Study 1: Cell Structure and Function.
Cell organelles: http://www.quia.com/jg/1624832.html (Word search, Concentration or Flash Cards)
Cell organelles and Photosynthesis review: http://www.quia.com/ba/265821.html (Battleships)
Cells – Who wants to be a millionaire? : http://www.quia.com/rr/450977.html
The cell and plasma membrane: http://www.quia.com/cb/447399.html (Challenge board)
Stages of Mitosis: http://www.quia.com/rd/161026.html (Ordered List)
During the two week break make sure you read through Chapter 5 and start answering the Chapter review questions. Take study notes, including definitions of key terms and important concepts. You could also draw concept maps for each of the digestive, respiratory, excretory and circulatory systems. Compare the nutrition and transport systems in plants and animals. You may find the following sites helpful:
BBC Human Body Interactives
National Geographic Human Body
Incredible Human Machine