A Gentle Reminder

If you were one of the students who did not take the quiz on Monday or Tuesday before Thanksgiving, you'll need to take it as soon as we get back to school.  Please be prepared to take the quiz during lunch on Monday or Wednesday.  Thank you!

Jokes About Viruses and Bacteria

Happy Thanksgiving!  After you remember to be thankful for enzymes, here are a few jokes you can tell around the dinner table:

It's Time for a Quiz!

The 7th and 8th graders are having a quiz on viruses and bacteria on Monday 11/23/09 and Tuesday 11/24/09.  Anyone who's absent can take it when we return from Thanksgiving break.  Here's a copy of the Review Sheet:

VIRUSES

What is it? (definition)

Is a virus living?  Why not?

Origins of viruses (their evolution)

How a virus invades a cell

How a virus reproduces

How a vaccine works

The two ways in which antibodies can help fight against a viral infection

How a white blood cell helps in the fight against a viral infection

 

BACTERIA

What is it? (definition)

How  bacteria reproduce (duplicates all of its parts and splits into two.  This is called FISSION)

Ecological roles of bacteria:

• nitrogen fixers

• other bacteria involved in the nitrogen cycle

• decomposers (produce ammonia!)

• photosynthesizers

• Inside the bodies of animals, where they help digest food, make vitamins, 

and perform other vital functions.

• Some bacteria infect other living things and cause disease.

 

NITROGEN

Why is it important to living things?

Why are most of the world’s living things dependent on bacteria for nitrogen?

What happens to nitrogen when we say it is “fixed”?

What is a “nitrogen-fixing plant”?

Which nitrogen compounds are easily taken up by plants?

Why are we once again in awe of enzymes?

The World of Microbes

This past week in science class, we have been learning about the world of the tiny and the world of the very, very tiny. With students, teachers and the general public concerned about infection by the H1N1 virus, it seems to be a good time to begin our study of microbes. There is a very important link between bacteria and plants, but we'll explore that later. For now, we've been looking at the scale of microbes, i.e. their relative size, primarily through this ultra-cool website Cell Size and Scale. We've also been learning about differences between viruses and bacteria, specifically examining how viruses invade and reproduce in one's body. A video produced by National Public Radio has done a fantastic job depicting this process; it can be found on the site Flu Attack! How a Virus Invades Your Body. And finally, everyone got a big kick out of these suggestions on alternative greetings during the flu season: Don't Gimme Five!

Classification of Living Things

     

            Indian mongoose

         Herpestes javanicus 

In addition to working on their plant experiments last month, students studied the classification of living things. They learned how to use the taxonomic ranking system through a classification activity designed around the University of Michigan Museum of Zoology's Animal Diversity Web, a phenomenally rich website devoted to providing an "online database of animal natural history, distribution, classification, and conservation biology". Many students wanted to continue exploring these topics at home; click on the link if you're interested in doing so!

For the activity, students were asked to use to website to list the taxonomic ranks,  first for four assigned and closely related animals (Indian Mongoose, striped-necked mongoose, meerkat and pygmy spotted skunk), then for four closely related animals of their own choosing. The requirements for the second four were that two be of the same genus, three be of the same family, and all four be in the same order.  The students tackled this task with enthusiasm, and this was reflected in the high quality of their work!  The assignment not only exposed them to the construction of classification systems, but also provided an understanding of how the shared evolutionary history of different species can be examined through their classification.