Middle School Biology 19 – Predator & Prey

The middle school class did the same fox and rabbit game that the high school class did last week and you can read about it in the last post.  Here’s a graph from one group, you can see the rabbit population increases quickly and once there is a pretty big rabbit population the foxes start to reproduce and their population takes off as well.  But once the fox population gets larger, the rabbit population takes a plunge as they get eaten by all the foxes.  Pretty soon the foxes die off as there are no more rabbits to eat and it starts all over again.  One student suggested that we make the ecosystem/field smaller each generation to simulate humans encroaching on their habitat.  This is a great idea and I might have one group do that next time while the other group plays with a constant size habitat.  It would be interesting to see the differences.

For the graph, I labeled the axes and then gave copies to the students since they are still learning how to make graphs and we were running out of time.

We also had the baby bunnies and guinea pig back for the third week in a row.  Here are the photos of the bunny for comparision. Its amazing how quickly they change.  The guinea pig really did change much except for its size.

bunnys just 4 days old

bunny one week later

High School Biology 18 – Ecology

Students read Chapter 13 from Holt Biology, or Chapter 28 in Biology: Life on Earth and watched the following videos before class.

I has the high school students make terrariums like we did in the middle school class. Two of them actually had large glass bowls and put in two small plants and took a leaf off an African Violet and put it in their terrariums.  African Violets are easy to propagate and will grow a whole new plant from a leaf – a separate lab we’l be doing later in the year.

High school students did a few interactive notebooks activies similar to the middle school class and then did the Traveling Nitrogen Activity where they worked their way through the nitrogen cycle.  I printed out the dice codes and stations, spread them out on the table and put some of the white board.  Each student started the nitrogen cycle at the station closest to them.  Some of the stations were Ocean, Atmosphere, Living Plants, Animal Waste, etc.  At each station students rolled a die and then read off the station sheet to see what happend to their nitrogen atom.  For example, I started at the Ocean, rolled a 3 which meant my nitrogen was absorbed by a living plant. I then went to the Living Plant station, rolled a 3, which means the plant died and I moved on to the Dead Animals and Plants station.  From there the dead plant decomposed and the nitrogen entered the soil, where it was aborbed by a live plant, which then died…. and so on.  The students could stop if their nitrogen visited every station but some got stuck cycling between just a few stations.  I really like this activity because I think the students are more likely to remember all the ways nitrogen moves around the environment, having acted it out, instead of just reading it.  Students wrote down a list of stations as they visited them or drew them out as in the photo above.

As a bonus, one of the families brought their baby bunnies and baby guinea pig to class for show and tell.  It was really amazing to see them both because even though both are only a few days old, the guinea pig looks just like a small adult, eyes open, teeth, fur, yet the baby bunnies, who are actually older, barely  had fur and their eyes aren’t open yet.  I’m hoping they will bring them back in a week or two so we can see how they change.

 

Middle School Biology 18 – Ecology

This class started with a Crash Course Ecology video on ecosystems and  “How Wolves Change Rivers” which is about the how the reintroduction of wolves to Yellowstone affected many aspects of the ecosystem, including where the rivers flow!

Since we’re studying ecosystems, the kids put together small terrariums using large glass jars.  Students put a centimeter of small pebbles in the bottom of their jars, then sprinkled some charcoal over the rocks.  Next came the moistened potting soil (1/2 cup of water for every 2 cups of soil, mixed in a large plastic bag) and a small plant.   Directions and a list of suitable plants are on  kidsgardening.org.  I found some of the pink polka dot plant and small ferns at the local nursery.

If we got the moisture level correct, we shouldn’t have to open them to water the plants.  Terrariums should be put where they will get some sunlight, but not in direct sunlight – they might overheat.  If too much water condenses on the inside of the glass you should take the lid off to let some of the water evaporate. If the plant looks like it needs water, then add some more water to the system.

Finally we added some pages to our interactive notebooks.  The first one was a lift the flap on the evidence for evolution (above right), which can be found in the Evolution, Natural Selection & Adaptation – Interactive Notebook Activity Pack by Getting Nerdy with Mel and Gerdy.  Under the flaps are a few paragraphs,  which they have to complete,  talking about the comparision of embryos, DNA, fossils, homologous and analogous structures, etc.  I had planned on doing this page last week but we ran out of time.

The second interactive notebook page (left side of photo) was about Producers, Consumers and Decomposers and is from the Ecosystems & Ecology Interactive Notebook Activity Pack by Getting Nerdy with Mel and Gerdy.