Saturday, 12 September 2015

The Human Evolution Zoo Trip

Year 13 Bio has been learning about Human Evolution for the last 2 weeks; as you can see below, Mokani has been receiving encouragement and support in his learning from Bones aka the freshly renamed "Sally the Skelly"

On Thursday last week we attended the Auckland Zoo Trends in Human Evolution session. This began by students comparing the skulls of a human, chimpanzee and gorilla. 

Key vocab about the skull differences included:
Foramen magnum
Zygomatic arches
Sagital crest
Nuchal crest
Masseter muscles (chewing muscles)
Brow ridges
Parallel (hominid) or parabolic (human) jaws and teeth
Protruding jaws
Canine teeth for aggression or not

Next, in pairs or threes students were given 2-3 skulls and asked to work out which was the most primitive, and which was the most recent, using what they had just learned from the compare-contrast activity.

Sela and Siale making friends with their skulls

Mokani and John looking at the zygomatic arches (cheek bones)

Rapture thinking about her skull.. 

Our student teacher Miss Graaf sharing her knowledge with the boys.

Then we compared the full skeletons of humans and gorillas, which from top-down included:
shoulder joints,
shoulder blades, 
rib cages,
spinal shape,
arm length, 
wrist joints,
palm length,
finger curve or not,
thumbs and grips (precision grip for humans),
pelvis shape,
gluteus maximus attachments and size
valgus angle,
leg length,
ankle joints,
grasping big toes or straight big toes,
arches in feet

The next activity was to bring all the skulls to the table and try to work out their order overall. This also included working out which skull was Ardi and which one was Lucy!  Turns out that Lucy also had a male friend with her, showing sexual dimorphism as his skull was significantly larger than her own. 

We found out that the main pattern that has developed over time is an increase in cranial capacity (cc), or brain size in comparison to body size. Species in the Homo genus have much larger brains for their size, and humans in particular have a large forehead with room for a frontal lobe. We know what frontal lobes are responsible for because of Phineas Gage's injury with a tamping iron... Having a larger brain allows for more complex behaviours, planning, problem solving, and communication. 

Then we moved on to tools! Everyone was given a bag with a replica tool inside of it, and asked to put their hand inside and imagine how to hold it, whether there was a comfortable way, what it might be used for.. then we took them out, looked at them, and grouped them:

Oldowan tools are associated with Homo habilis (aka Handy Man) and are also called Pebble tools. They are basically the core of a rock shaped by a few blows to have a sharp edge. They were mostly used for smashing or crushing. 

Archeulean tools have a typical teardrop shape. They are kind of like the swiss army knife of tools - they can be used for smashing, crushing, throwing, stabbing, slicing, as a hand axe etc. The core of the rock is still the main tool. These teardrop Acheulean tools remained fairly unchanged for 1 million years! 

1.5 million years ago (mya) if you were holding this Acheulean tool, you were holding the most sophisticated technology on the planet. 

Mousterian tools were less generalised and more specialised for different jobs like slicing, cutting, spear heads, hand axes, etc. They are usually made from flint. They were often made from the flakes that come off the core, and require a lot more planning to make.

We concluded our trip with a wet walk around the zoo in the rain for an hour. We got to see a baby giraffe, the new Auckland elephant, 2 sleepy lionesses, a curious meerkat who came and said hi, a red panda doing laps up and down a tree and John holding a convincing conversation with a flamingo. 

In other news, Tamaki College may be getting some of our own ancient skulls from +Karen Ferguson and her awesome 3D printer! Different African fossils can be downloaded from this website, if anyone else has a 3D printer at their school :)

1104 Learns about Density

We've started a new topic for 4 credits at the end of Term 3! And depending on how hard we work, we could even do ANOTHER 4 credits in Term 4! On Thursday we started looking at different types of metals, making observations, and we weighed 1 cm cubed samples of them. 

Then yesterday we graphed their density (g/cm3) before learning what density actually is - the amount of particles packed into a given area. Objects or liquids that are more dense have more particles packed into the same volume.

First we watched this video.

Next I revealed to students the list of the liquids available to them and gave them each a piece of paper with two blank test-tubes drawn on it. Students got to draft a density tower that they thought would be most accurate, and then have a second guess by drawing a second test tube with some of the orders of liquids changed around.

The liquids we used were:
water (pink food colouring)
dishwashing liquid (green)
olive oil (yellow)
conditioner (white)
water + corn starch (bright red, lots of food colouring)
golden syrup (golden)
shampoo (white)
soy sauce (brown)
sunscreen (white)
baby shampoo (yellow)

I quite liked this activity because there was a lot of discovery learning happening. I didn't know the exact order in advance, and there were a lot of questions being thrown around like "is soy sauce going to sink through water?" which I got to answer with "I don't know, go and get a test tube and find out  before you add it to your density tower." There was also some logical thinking happening, like when Duui decided that dishwashing liquid would be more dense than water because when he uses it at home it moves to the bottom of the sink, and Brandon had a think about oil spills and water. 

I discovered that soy sauce is more dense than dishwashing liquid, because it sank right through the dishwashing liquid in my tower and sat on top of the conditioner layer. 

Most students guessed that the golden syrup would be the most dense. 

Here are some photos from our class:

Mac, David and Duui gently adding the next layer to their beakers. 

Mac's first attempt

Students working and cleaning out their beakers after failed attempts. It was quite good to get it wrong and have a layer sink through, because then they knew to add it earlier as it was more dense.

My attempt.

Mac's best "scientist face" as he studies his density tower - many more layers this time!

I think that this lesson (messy, loud, and a little silly) was a good one to illustrate density. 

Next week we'll have to start thinking about why cars and planes might be best made from more or less dense metals.. hmm...