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Biology

Big History 016- Life

Today we started Unit 5, Life, of the Big History Project.  Since most of the students were in my biology class last year I didn’t want to repeat the same Darwin/evolution classes so I searched the web for a tree of life activity.  I found this very cool website on NOVA that has various tree of life ‘puzzles’ for you to solve.  I was having some difficulty figuring it out but my 15 year old came up behind me and immediately solved the puzzle. I emailed the link to the students before class.

We started class by taping in the Threshold 5: Life card in their notebooks and the ‘How Closely Related Are We’ activity from the Big History Project website.  In the later activity they have to figure out closely related we are to chimpanzees, fruitflies, and bacteria to name a few – its just a matching activity.  I let them discuss it among themselves for a while and then we watched some videos off youtube.

Sci Show on Mary Anning

The Evolution of Life on Earth by ASAP Science

Can Science Explain the Origin of Life by Stated Clearly

and Are We Really 99% Chimp? by MinuteEarth.

I also recommend watching First Life by David Attenborough – it can be found on youtube, but since its an hour long we didn’t have time to watch it in class.

After the videos we did modeled the process of evolution with legos!  This project was a great hit and the kids worked on it enthusiastically for over an hour.   You have each group start out with a very simple lego creature consisting of just 2 bricks – a body and a head.  They have a deck of cards which consist of three kinds of cards: repetition, mutations and split.  If they draw a repetition card, their creature stays the same, but if they get mutation they get to add or change something on their creature.  IMG_1661If they get a split card it means the population is split so they have to make another creature and each population will mutate/evolve separately.  By the end they will have 3 or 4 very different looking populations.  Students are sketching each generation in their notebooks.  I found two sources for this activity, Lego Tree of Life  – this one actually made a whole new creature for each generation but we didn’t have enough legos to do it that way, and Lego Cladograms on the betterlesson website.  The betterlessons site makes you join but it was free and then I was able to download the cards and a powerpoint file with the instructions. They also had videos demonstrating how to do it in a class.  I hadn’t come across this site before and it warrants further exploration because this was a great activity.

IMG_1709

Here are a few other species that evolved in class today, and just incase you’re wondering about the stars around the ‘cutey pie’ at the bottom of the chart above – it mutated to become ‘magical’.IMG_1712IMG_1710IMG_1714

 

Big History 009 – Threshold 4 & Planets

We started Unit 4.0 in the Big History Project this week which means we’ve reached Threshold level 4, the formation of our solar system and planets.  I had the kids tape in the Threshold 4 card into their notebooks as they arrived and then we watched Crash Course Astronomy video on Exoplanets because I wanted to make sure they realized that our solar system is not the only one with planets.  

After the video we discussed how our solar system formed and I asked them what they knew about each planet.  Then they did the Big History Project lessoplanet card sortn 4.0, Planet Card Sort, and cut out the pictures of the solar system in various stages of development and tape them into their book in the proper order.

The last activity, making a flip organizer for the planets, took the longest and some kids didn’t quite finish.   I got this idea from the Earth’s Place in the Universe Interactive Organizer, but I was disappointed to see they gave the planet data in miles, and the acceleration due to gravity in ft/s^2!  There was no way I was handing those out, so I redid the activity in metric and changed a few of the facts, gave the mass of the planet in Earth masses so they could tell how much more or less massive the planet was compared to Earth. I also gave them blank cards with just a circle on them so they could color it in to look like one of the planets, put the name of the planet on it and then they had a sheet of planet facts they had to sort through and put the right facts on each card.  I had the facts clumped together so one table had orbit radius on it, so they could actually just put those in numerical order and the one with the shortest distance from the sun must be for Mercury, etc.planet organizer  The other set of facts had orbital period, how long it takes for the planet to go around the sun, so again, they could put the table of facts in order, shortest period would be the Mercury, etc.  I did include Pluto on the organizer because everyone loves Pluto, especially with the latest data from the New Horizon.   I had left the number of moons fact empty so they had to look that up on the web or in the Solar System app by Touchpress.  There was also a spot on the card for them to write at least one unique feature about the planet, for example, Venus is considered Earth’s evil twin, Saturn’s famous for its rings, Jupiter for its spot.  Most kids didn’t get to this in class because we ran out of time.  But when taking pictures for this post I noticed my son put Matt Damon on Mars… lol, we’re big fans of The Martian.mars

Biology Experiments with Wisconsin Fast Plants

Wisconsin fast plants are genetically altered plants that grow really fast and are great for science experiments.  You can order them from Carolina.com either as just seeds or in kits.  We used the Wisconsin Fast Plants® 72-Hour Genetics Kit which comes with 4 seed packets from 3 different generations so you don’t have to spend months growing each generation, harvesting the seeds and then planting the next generation. The kit also comes with petri dishes and everything you need to do the experiment.    The kit I bought was for my class, but they do sell kits for individual students and a variety of kits are available for different experiments.

fast plant seedsThese are called fast plants for a reason. We put the seeds on moist paper towels in the morning and they were sprouting that night before we went to bed!  The first photo was taken about 14 hours after setting up the experiment and the second one is only  3 days later!  You can see from the second photo that the seedlings have some variety  – some have purple stems and some are green.   If I remember there are also some that are hairy and some that are smooth.  The kids counted how many purple vs green stems there were in each generation and figured out which trait was recessive.  This whole experiment can be done in 3 days! fast plants day 3 No need to keep it going for weeks and weeks, though if you have a kid who wants to do that, you can start with two pure seed packs with different traits, grow the plants, fertilize them (did you know they sell dried bees to put on sticks to do this??), harvest seeds and then start all over again.    Either way these fast plants are excellent for biology, genetics or even a little botany fun.

Biology: Osmosis Experiments

osmosis red onionFor the chapter on cell membranes we did two labs last year.  The first experiment involved looking at red onion cells under the microscope while adding salt water to the slide.  The salt water increases the concentration of solute outside the cell so water leaves the cell causing it to shrink.  This is very obvious with the red onion cells because the red/purple area shrinks away from the cell walls as you can see in the photo.  The cells at the bottom of the picture have not be in contact with the salt water yet so they still look ok.  close of red onion cellAs we watched through the microscope we saw the membranes shrink and the red/purple color become more concentrated in the center of each cell – this is called plasmolysis and you can find the lab I used at www.explorebiology.com.

The second lab we did involved chicken eggs.  A few days before class, we soaked the eggs in vinegar to dissolve the shell.   During class the  students found the mass of the eggs and made a prediction in their lab books about what they thought would happen to the eggs.  The eggs were then either soaked in water or corn syrup.  eggs osmosisEvery 30 minutes they pulled the eggs out of the liquid, patted them dry and recorded their mass again.  Everyone was very surprised to see that the egg soaking in corn syrup actually shrunk and the egg soaking in water swelled up.  Students found the percent change in mass of each egg and made graphs of their results.  The egg in the corn syrup, hypertonic solution,  shrunk (egg on the left in the photo) because the water left the cell (yes, a chicken egg is just one big cell!) to try to dilute the sugary surroundings, while the egg soaked in water, a hypotonic solution, absorbed more water trying to dilute its interior (egg on the right in the photo). You can see in the picture if was a pretty obvious change.  The middle school class did these labs too, but we only measured the eggs twice, at the beginning and the end of class so it was more of a demonstration.   We actually let the eggs soak for a few days after class,  just to see how much more they would change. shrunk egg The egg soaking in water didn’t really change much after the first few hours but the egg in corn syrup basically turned into just the yolk (see photo).

biology inquiriesThis and some of the other labs we did can be found in Biology Inquires: Standards-Based Labs, Assessments, and Discussion Lessons by Martin Shields.  

DNA Pop Beads for Biology

biology textLast year was our first year doing a more rigorous high school science course.  As mentioned before we used a college text for non-majors and I think it worked out pretty well.  I thought it was a pretty readable textbook.  We used the second to most recent edition of Biology: Life on Earth with Physiology (9th Edition) to save some money.

popbeadsOne of the activities we did last year was to make stop motion movies of meiosis and mitosis using pop beads. The kids had fun doing this and I think acting it out helped them understand the process.  I bought the Neo Sci DNA Pop Bead Assorted Kit, 1500 pieces  on Amazon.  magnetic centromereThere are smaller sets available but I was using it for my class so I bought a big set.  You will also need to buy some Neo Sci Plastic magnetic centromeres for DNA Pop Beads to hold together the chromosomes. Make sure you buy MAGNETIC centromeres.  The kids made the movies on a white board so the magnets helped hold everything in place and it was easy to just redraw the other cell components for each frame.  We did this activity in both the high school class and the middle school class, which was using Real Science Odyssey Biology Level 2 as their text.   As you can see in the movie on meiosis you can even model the crossing over of genes (swapping of yellow/red segments) which helps increase genetic diversity in the four daughter cells (none of which are the identical).

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