11Feb2016 – First meeting of Pond Biology

What we did:

– – We opened with one of the essential questions of Biology: What is alive? I actually asked “what is alive in this room”? We decided we were alive, and there were the dogs and a plant. Someone said “the air?” and we talked about air containing oxygen and nitrogen, and yes, maybe microorganisms that we cannot see with the naked eye. When we sneeze, we release germs (bacteria and viruses) which are alive and float around in the air, waiting for their next victim.
– – I then brought out my “algae ponds”, which are three containers that I left outside to fill with rainwater and then sit in the sun for weeks until class started. There was some garden soil in the bottom to provide spores, eggs, and other dormant forms of our algae and protozoa, but other than that, I added nothing to the collected rainwater. We gave the kids hand lenses and flashlights to look at the ponds. I also had some test tubes and glass jars with water in them, and challenged the kids to try and figure out what it is about a magnifying lens that magnifies. We had some good guesses (the water, the clear glass), but then I showed them the glass jar with square and flat sides (and doesn’t magnify). I got a “the roundness of the glass!”, and so we were on the right track. More about microscopes and stereoscopes as we go on…
– – Now the compound microscope was set up, and I demonstrated how to make a wet mount slide with the algae from the pond bins. It sounds complicated, but is essentially placing a small drop of your sample on the slide, and then placing the cover slip (the small piece of glass that goes over the sample) at an angle to the drop so no air is trapped under the cover slip. Since we are trying to see live organisms under the scope, this is the classic method for keeping them motile and alive.
– – Our compound microscope is hooked up a big monitor so everyone can see the action (but we will need to come up with a system to ensure that everyone has a turn with the mechanical stage and focus knobs). And then everyone saw a paramecium moving across the screen in the middle of the algae!! So exciting! We then discovered that they can move very quickly and trying to keep up with them with the stage knobs is very difficult – they do not stay still. We then spent time looking through the slide to try and see more protists and we might have seen more paramecia (link to online pictures), a hydra (link to online pictures) and other ciliated flagellates (link to pictures).
– – There were also several stereoscopes, or dissecting scopes on the table for more wet mount observations of the algae in the bins.
– – We also learned that stereoscopes “see” in 3-D like our eyes, and are used at lower magnifications than compound scopes, which require very thin slices of tissue to be used at 400X and up. You can look at pennies or a live insect under a stereoscope, which you cannot do with a compound microscope. Wet mounts with a compound scope is cheating a little, since we are trying to use it as a stereoscope, but at a higher magnification than usual stereoscopes. Fortunately you can make a drop of water very flat (why you put the cover slip on top) so it works extremely well.

Some pictures from my preparation for class and during class – these are ALL pictures from slides made from the algae bins.


IMG_1571_with text

We will return to the question of these boxes, they are a central tenet of biology: cells. Can you think of why algae would be organized in boxes? How are they connected in long strings? And another big question: how do they make or obtain their food? What are they eating? Or making? Why are they green?

See below for a complete gallery of pictures – I cleaned up the noise and blurriness as well as I could, but the good news is that I fixed the light bulbs in the microscope and tweaked some other settings, and we will have much brighter and clearer pictures next class. We’ll see what we can find, and some other surprises.

Extra resources for further reading and exploration:

We will be doing more work about protists in the weeks to come, but I since I won’t be able to go into great depth on some of these topics, I will try and post good links for learning more. A very good place to start is to try and understand the overall family tree of protists, plants, fungi and animals (all eukaryotes, or organisms that have a nucleus). The entire domain of protists is far more complicated and contains many more members than our own small kingdom Animalia. Think about it, they’ve been evolving for almost 3 billion years! In fact, scientists think the kingdom Protista should really be divided in several kingdoms; as the page from the UCMP says: We retain the word “protist” as a convenient term to mean “eukaryote that isn’t a plant, animal, or fungus.”

A good introduction to protists without too much jargon: http://schoolbag.info/biology/living/138.html
The clade diagram lower on the page is a clear depiction of the different types of protists, and then there is an atlas of the most common types lower down. One of the hardest parts of learning about protists is that there are an overwhelming amount of them! It is important to focus on a few to begin with.

From UC Berkeley’s Museum of Paleoanthropology: http://www.ucmp.berkeley.edu/alllife/eukaryotasy.html
This page has a clade map of the eukaryotes, and you can click on the picture for a quick introduction to each type. The scientific names might be a little confusing, but click through to the introduction.

Here’s a quick description of what phylogenetic classification and clades mean: http://evolution.berkeley.edu/evolibrary/article/_0_0/evo_10

The top of this page has a more descriptive clade picture showing evolutionary relationships: http://plantphys.info/organismal/lechtml/protista.shtml
The UCMP link above also has the relationships (the black lines), but it is hard to read.

18Feb2016 – Second Meeting Pond Biology

Plan: to continue looking at samples of our pond water under the microscopes, plus learning about paramecium, hydra and ameoebas in depth to begin our study of protists. We’ll also try and start exploring the family tree of the Kingdom Protista, as well as discussing what makes something alive, the importance of cells, and some vocabulary words (to make reading about protists a little easier).

What we did at our meeting:
– – We spent a few minutes talking about the building block of life: the cell. There’s a picture from the previous class of an algae species with green “boxes” that we looked at to show a perfect example of cells (I think this algae is in the Ulothrix family, click here for link to page of images). The cells are attached but are not working as a unit together, but rather are forming what is called a colonial unit of cells: attached together but each working as its own little organism.
– – We also talked briefly about atoms (the smallest unit of a pure element that can still exhibit the characteristics of that element), and someone mentioned molecules. Molecules are the smallest unit of a compound, which is 2 or more elements bonded together to make a new chemical.
– –

Extra resources and learning links:
Therese sent this article link to a scientist who posts pictures of pond creatures on Instagram:
Here’s the Instagram page:
It was SO fun poring over her pictures and descriptions, it is really worth a look!
Kid friendly page explaining different types of protists:

Here are some fun videos showing paramecium, hydras and amoebas:

25Feb2016 – Third Meeting Pond Biology

Essential questions for class:
– – Are really replicating a pond with the algae bins? What other lifeforms would we find?
– – How are protists related to animals and plants? What does the family tree look like?

Plan: We are going to make student “ponds” (using small restaurant bins with tops) to observe over time. We’ll start with sand/gravel, adding some algae water from the class bins, and some water plants.

Report on class:

Draft for third week of pond biology class

We started with what might seem like a detour, but evolution and natural selection is a cornerstone of modern biology. When studying pond biology and the world of protists, fungi, plants and animals (the 4 main categories of eukaryotes), it is important to understand how these life forms evolved over time to  what they are today. 

And before we can even start with evolution, we need to think about classification. All I mean by classification is the system we use to look at life forms on earth in a way that shows how they are related and connected to each other. For example, would we put fish into the same category as birds?  It seems obvious that fish and birds aren't very related, but are fish and birds more related than fish and bacteria? Hmm. This is pretty complicated. 

To give the kids a taste of what a huge job this is, we started class with a quick 20 Questions game: I told them that I was thinking of a machine. We then brainstormed all the differents kinds of machines we could think of: washing machines, cars, computers. We consolidated some of the ideas into one category, but quickly realized that splitting up the category of "machine" is tough. Many things are in more than one category, and it is hard to come up with a simple system of classification. 

20 Questions is when someone thinks of an item (usually no clues), and then you ask questions to give you clues in order to guess before you run out. Someone asked

Answer: a CD player

I highly recommend playing 20 Questions in general, it is an excellent logic game, and if you do life forms, you play with some of these classification and evolution ideas in a fun way. Try it and see.

Back to class: the first scientist to even attempt the classification of life on Earth was Carl Linnaeus. We could do an entire class on Linnaeus and the eventual classification system we now use every day in biology, but here are some learning links to get you started:

Short and sweet overview of Carl Linnaeus:

A little dense with information, but good for parents and those really interested: http://www.ucmp.berkeley.edu/history/linnaeus.html

Really interesting (but again, dense) post about how classification of life forms (usually called taxonomy by biologists) is still a controversial and still not settled topic in biology today: http://www.ucmp.berkeley.edu/history/linnaeus.html

Taxonomy is complex and difficult.

After our quick introduction on taxonomy and classification(more next week), we started in on evolution. Someone asked "what is evolution?", and what a good question that is. I didn't use this in class, but the official definition is "descent with modification", but that is pretty useless unless you are already know your evolution! 

Descent = passing traits or genetic information (our DNA) from parent to child. It is a one word description of the numerous generations that have happened for all species of life on earth.

Modification = change in genetic information. Change happens on Earth all the time that has nothing to do with evolution (leaves falling from tree, geologic changes in a mountain range over millennia), but it is that change being incorporated in the DNA of a species that is the foundation of evolution. 

What did we talk about in class? We talked about evolution being change in a species over time. As an example, we talked for a little bit about how dogs have evolved from the Grey wolf. This is an example of artificial selection (or man-driven evolution), but it does illustrate the important components of evolution. Here's a great video about how dogs evolved:

3March2016 – Fourth Meeting Pond Biology

Essential questions for class:
– – How did your plants and algae grow? Did you see any other lifeforms appearing? Do you think there are protists in the water too?

Plan: We are going to make student “ponds” (using small restaurant bins with tops) to observe over time. We’ll start with sand/gravel, adding some algae water from the class bins, and some water plants.

10March2016 – Fifth Meeting Pond Biology

Essential questions for class:


17March2016 – Sixth Meeting Pond Biology

Essential questions for class:


24March2016 – Seventh Meeting Pond Biology

Essential questions for class: