LS1C – Matter and Energy Flow in Organisms
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LS1C – Matter and Energy Flow in Organisms

Hi. It’ Paul Andersen and this
is Life Science Core Idea 1C (LS1C). It’s on Matter and Energy Flow in Organisms. And
by the time students graduate from high school they should really have a good understanding
of how matter is recycled on our planet and how energy moves through living material and
eventually becomes heat. And so if you’re teaching this a good place to start is with
plants. And so at the lower elementary grades you want to start by talking about what a
plant needs to survive. Basically they need two things. You need to give them light and
you need to give then water. If they don’t have those two things, they’re going to die
right away. But what do animals need? We need plants. And so this mouse is feeding on plants.
And this hawk is feeding on the mouse which fed on the plants. And so that’s a good place
to start. What are some of the requirements of life. And light and water are a good place
to start. But it’s more complex than that. And so as we move through elementary we want
to add two areas. We want to add material that we get from the soil, minerals. And minerals
that we get from the air. And so basically if we look at a plant, what does a plant require
to live? It needs light and water. But it also needs minerals that it’s taking out of
the soil. And so it’s talking those in through its roots and it’s also getting minerals from
the air, in the form of carbon dioxide. And so if they don’t have all of those things
they can’t survive. But what about animals? We don’t need light to survive, but we do
need water and we need plants. Because those plants are going to contain minerals that
we require. And then we’re also going to get minerals out of the air in the form of oxygen.
But there are some organisms, like the bacteria that live in the gut of this cow that don’t
require oxygen. And we call those anaerobic organisms. And so all of this matter we get
from the earth or from plants that get it from the earth. But we also get energy and
that energy again comes from plants. As you move into middle school you want to start
talking about how that actually occurs. I mean how does that matter, how does that energy
get stored in organisms? And the big process is called photosynthesis. Now you don’t want
to get too much into the details of the light reaction and the Calvin Cycle and electron
transport, but you do want to talk about photosynthesis and really the overall of what’s going on.
And so the nice thing about the work photosynthesis is that it’s broken into two parts. You’ve
got the photo part and the synthesis part. And so in the photo part, plant or you know
protists or algae or phytoplankton are all taking in light and water and they’re using
the energy of that light to activate chemicals inside the plant. They then use that energy
that’s stored to convert carbon dioxide into sugar. And that’s the synthesis part. We’re
making something out of the carbon dioxide. So let’s go over that again. We start with
the light and the water and in the light reaction we store that energy and then we use that
energy to take carbon dioxide and convert it into a sugar. So that’s photosynthesis.
What are we using the sugar for? Well in plants they’re using the sugar to build the plant.
And so the sugar that eventually makes the cellulose that eventually makes the wood in
a tree comes from this process of photosynthesis. And it’s important that you understand that
matter is actually coming in from the carbon dioxide that the leaves take in. And so most
of the mass of a tree actually comes from the air. Comes in from carbon dioxide. So
they’re taking in the sugar and they’re using that to build but they’re also using that
for energy. If we now look at organisms, so animals, where do we get our energy? Well
we get it from the food. In other words it’s in the sugar that was produced by the plants
that we eat or the animals that ate the plants. And so the way we release that energy is through
a process called cellular respiration. So how does that work? We’re taking in food and
oxygen and we’re using that to store energy inside our body that we can utilize. What
are the byproducts of that? Water and carbon dioxide. And what’s nice about that is that
those are used again in photosynthesis. Let’s go over that again. We take in food from the
organisms or the plants that we eat. We combine, using oxygen to store that energy inside us.
And it’s way more complex than that. But we can wait on that. And so there are some organisms
again, anaerobic that can just take in food and they don’t require oxygen to release that
energy. Now that’s kind of the energy, where it’s coming from. But we also build the parts
of cells. And so plants are not only using that sugar to release energy, but they’re
building the parts of the cell. And we can metabolize that sugar and use it to make DNA
and proteins and other things inside the cell. And so we’re getting the matter of life from
that. And so there’s definitely a flow, a flow of energy. And that flow of energy goes
from the sun to you. And so when you move your hand like that the energy of your moving
hand originally came from the energy in the sun. And so how does it flow? Well, it flows
into our food through a process of photosynthesis. That energy is being stored in plants and
it’s eventually being stored in our food. Now along each of these steps we’re loosing
energy and we’re loosing energy in the form of heat. But we’re taking that free energy
of the sun and we’re storing it in free energy of our food. We then use cellular respiration,
and we use mitochondria to do this and release this energy. To transfer energy to the muscles
in the form of ATP. And so as you move into high school, then you can get into more of
the specifics of photosynthesis, cellular respiration and even talking about ATP and
how that energy is transferred. But the big picture is this. Energy is going to flow through
life in one direction. The energy from the sun becomes energy in the plants, energy in
the animals, but eventually it leaves as heat. And if the sun isn’t there, if the sun were
to go out, then the plants die, the animals die as a result. And so it’s a one way direction.
We’re still conserving the energy. It’s just that were switching it into a different form,
eventually becoming heat. The matter is different. That matter on our planet is recycled over
and over and over again. And so what makes me up, that matter, used to be in the air
or used to be in plants or used to be in my food. I literally am what I eat. And it’s
recycled over and over and over on our planet. In other words there’s a set amount of water
on our planet and it’s just recycled over and over again. And so that’s matter. And
that’s energy. And I hope that was helpful.

16 thoughts on “LS1C – Matter and Energy Flow in Organisms

  1. Oops. Honestly don't know what I was thinking. I have tried to clear this up with an annotation. Thanks for that.

  2. The next generation science standards will guide science education over the next decade. Teachers from K-12 will be focussing on the same core concepts with greater detail. Hope that helps.

  3. Besides being an awesome explanation of that new upcomming standard, I also love these videos just to go through all that I've already learned at school. It's really quite amazing how much stuff you actually learn over the course of your life or rather, according to this plan, over the course of just 10 years!

  4. No, i looked online and from what i saw it is! i was LOLing at myself. Love your work btw. I am not a teacher but when i have my own kids i will be using these vids to help me get the big ideas across to them. x

  5. Now that we are teaching the NGSS standards in Illinois, your videos definitely guide what material needs to be covered at each level. Thanks

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