Hi. It's Paul Andersen and this is disciplinary core idea ESS2E. It's on biogeology.
And that's really how the life on our planet interacts with the planet itself. And so again
in summary there are four spheres on our planet. We have the geosphere which is going to be
the planet itself. We have the hydrosphere which is going to be the water. And the atmosphere
which are the gases on the surface. And so in this diagram, where these three things
come together, like right where, we're going to have the biosphere. That's going to be
where the life is on our planet. It's where these three spheres come together and allow
life to exist. And so you can see how these three things could effect life, but could
life ever effect the other three? For sure. And that interaction between the two, especially
the earth and life is going to be biogeology. So what's an example of that? Cyanobacteria
are bacteria. They've been around for billions of years. And when they started doing photosynthesis
on our planet, they started producing oxygen. And that oxygen on our planet started making
rock that was red. It was rusting. And so we saw these banded rock found within the
planet. And so the life was actually shaping the rock itself. Or changing the rock itself.
The carbon cycle is a great example to see how life is interacting with the planet itself.
And so as we go through photosynthesis, we're taking carbon from the atmosphere and actually
making sugar out of it. And as we do respiration, we're returning some of that into the atmosphere
as carbon dioxide. As we start to burn fossil fuels we're taking carbon that was locked
away in the earth. And we're releasing it into the atmosphere. And that's going to change
the atmosphere, the hydrosphere and even the earth itself. And bacteria are incredibly
important in this as well. And they're important in the nitrogen cycle. And so really the message
I'm trying to get is that we have landforms on our planet, the geosphere. And we have
life forms on our planet. And so as the landforms change, as we change our planet, the life
has to respond to that. And so what the life does is evolve. And the land will change again.
And the life will change again. So they're linked together. And so how do you teach this
progression. Well in the lower elementary grades we want to talk about life, plants
and animals. And we are animals for sure. What do we need? Well we need land to live
one. We need air to breathe. And then we need water. And so as we take all of these things
in, we also change them as well. So we're changing our environment. And we're doing
that by plowing the fields. As we chop down trees. As we use the water and as we put into
the atmosphere, we're changing our environment. And so as we move into the upper elementary
grades we want to explain to our students that living things affect the environment.
And so here's a great couple of examples. And so as plants start to live, the put roots
into the soil. And that's going to hold the soil in place. It's going to hold water in
the soil as well. And so by adding life, we're actually stabilizing that soil. Beavers for
example can build dams. And they're going to change the flow of the water or that hydrosphere
on the geosphere. And as we build dams we're going to do the same thing. As you move into
middle school you want to talk about landforms changing. And sometimes that's gradual and
sometimes it's dramatic. So meteor impact like this could be dramatic change to the
landforms. We could have volcanism. So volcanoes could change the landforms as well. And once
we have that change then the life forms have to evolve. And so what's an example of that?
Well dinosaurs are a great example of that. They lived on our planet for millions and
millions of years. And they went extinct relatively shortly. Why was that? We had changes to the
landforms. We had a meteor impact, an asteroid impact and that changed the climate. And they
couldn't adapt. But certain organisms could. And a group called the mammals did really
well and started to fill some of the niches that were at one time filled by the dinosaurs.
And also as we talk about middle school, students should understand that the life can actually
change the earth. And so this idea of cyanobacteria changing the earth. Adding oxygen to the atmosphere.
And adding oxidation to the rock is important. And I read that bacteria can even help in
the formation pyrite or fool's gold. I think that's really really cool. And then as we
get into high school we want them to understand this whole idea of coevolution. That the landforms
on our planet will constantly be changing. As they do, life forms have to evolve in response
to that. But it's a never ending story. And I hope that was helpful.