Steve Trash Science
What Is Science?/Food Webs
7/1/2023 | 26m 46sVideo has Closed Captions
Explore the meaning and value of science. See how food webs connect plants and animals.
Explore the meaning and value of science. See how food webs connect plants and animals.
Problems playing video? | Closed Captioning Feedback
Problems playing video? | Closed Captioning Feedback
Steve Trash Science is a local public television program presented by APT
Steve Trash Science
What Is Science?/Food Webs
7/1/2023 | 26m 46sVideo has Closed Captions
Explore the meaning and value of science. See how food webs connect plants and animals.
Problems playing video? | Closed Captioning Feedback
How to Watch Steve Trash Science
Steve Trash Science is available to stream on pbs.org and the free PBS App, available on iPhone, Apple TV, Android TV, Android smartphones, Amazon Fire TV, Amazon Fire Tablet, Roku, Samsung Smart TV, and Vizio.
Providing Support for PBS.org
Learn Moreabout PBS online sponsorship- Magic is creating the illusion that you can defy the laws of na (upbeat music) (upbeat music continues) (upbeat music continues) (drums rolling) (crowd cheering) - Magic is creating the illusion that you can defy the of nature.
- Science is the study of how the natural world works.
This is science.
This looks absolutely delicious.
After I eat all this, I am going to be so full, so satisfied, so, wait a minute, there is no food No food, and none of the energy and all living things need to su Energy.
Living things need energy to sur Energy is a form of power.
We sometimes say it's the ability to do work.
All living things need food energy to survive, like carbohydrates, fats, and pr Some living things make their ow others get it from consuming, well, other living things.
The food chain or the food web describes the transfer of energy in the form of food between a number of different le because these different trophic are linked together by what they This arrangement is often called a food chain.
These levels might also be shown as a pyramid with the first level on the bott Each level includes a number of plants or animals.
The first trophic level consists of producers.
Producers, also known as autotro produce their own food through a number of processes.
Most producers are plants.
Photosynthesis is how plants make their food.
Carbon dioxide and water with energy from the sun are the building blocks of photo Plants absorb the carbon dioxide that is released when animals br along with water that they absor mostly through their roots.
In the presence of sunlight, a process called photosynthesis takes place.
Photosynthesis produces a carbohydrate and oxygen.
The plant uses the carbohydrate and we humans, well, we breathe the oxygen that is released.
Without photosynthesis, plants couldn't survive and neither could we.
The plants need the food and we, we need the oxygen.
Cool, right?
Let's stop right here for just a Because I want to take another look at that word autotroph.
Words aren't just made up of random letters.
They're almost always made up of that have their own meaning.
Autotroph is no exception.
Part of that word, troph or tropho relates to nutrition.
A trophic level is a level of nu When used by a biologist, the word auto means self.
So, autotrophic means providing nutrition to oneself.
Okay, let's get back to producer There are other producers, but they're pretty rare.
A really cool process called chemosynthesis is how some bacteria produce food using sulfur compounds.
Also, there are different types that use melanin and, believe it or not, radiation to create energy for growth.
So, again, autotrophs in the first level of a food web, make their own food.
The next few trophic levels consist of consumers also known as heterotrophs.
These organisms cannot produce their own food and must consume either a producer or another consumer.
By the way, heterotroph is also a word that has two parts.
Troph relates to nutrition but hetero means other or differ A heterotroph gets its nutrition from a different or other source Okay.
So, the second trophic level, which is the first level of cons consists of organisms that eat p These primary consumers also known as herbivores, only consume producers.
Deer, cows, sheep, and some bird are examples of herbivores.
Herbivores don't have to be smal Elephants and giraffes are also herbivores.
The third trophic level consists of secondary consumers that are either omnivores or car Omnivores are animals who eat plants and other animals.
And carnivores are animals that eat only other animals.
Regardless, these animals eat primary consumers.
The next level consists of tertiary consumers that are, again, either omnivores or carnivores.
Regardless, these animals eat secondary consumers.
When describing a food chain, scientists almost always stop at This level consists of top preda which are also known as quaternary consumers or simply apex predators.
They may be omnivores, but usual Apex predators aren't necessarily fifth level consumer but they have no natural predato under normal circumstances.
The food chain has one more part and it's typically considered a separate trophic level.
The organisms in this trophic le don't hunt for living food, they are the decomposers.
Decomposers eat non-living plant and animal remains.
There are a few different kinds.
Some are scavengers, which are creatures that typically eat dead animals.
Detritivores, which are smaller that eat decaying plant and animal material.
Organisms like fungi and bacteri are the smallest decomposers.
Ultimately, decomposers return inorganic materials to the soil.
Again, this arrangement of level is often called a food chain.
It's not uncommon to see these l depicted with a single organism at each level.
In reality, though, flowers such as these daisies ar and their nectar is eaten by a lot of insect consumers, such as these butterflies.
Yeah, it's while butterflies eat daisy nectar, they also eat the nectar of these coneflowers as well as the nectar of other f They eat what is available.
Frogs eat butterflies.
But while frogs eat butterflies, they also eat flies and other small creatures.
Butterflies are also eaten by predators other than frogs.
Herons eat frogs.
But frogs are also eaten by possums and raccoons.
Something that's important to no is that when energy is transferred from level to level, a lot of the energy consumed by is lost as heat or used for move or other biological functions.
Because of this, the number of animals at each tr is fewer than the level below it There are relatively few animals at the top level.
This results in the web taking t of a triangle or a pyramid.
The food web is oftentimes shown Let's take another quick look at an example of a simple food chain.
Remember, in real life, things are a lot more complicate than this illustration.
Grasses found in many different produce seeds as a part of its reproductive process.
Grasses, of course, are plants that produce their own food.
They are autotrophs.
When you find grass, there's normally a lot of it.
Mice, common omnivores, eat grass and grass seeds.
It's good there's a lot of grass because they eat a lot of it.
Mice though, don't have populati that equal those of grass.
One mouse eats a lot of grass in its lifetime.
Snakes eat mice.
Snakes eat a lot of mice so there are a lot fewer snakes than there are mice.
As I said earlier, as we move up through the levels of the food chain, the number of consumers get smaller and smaller.
Foxes eat snakes, and again, there are fewer foxes than there are snakes.
Finally, in this simplified food there's this guy, the Eurasian eagle-owl.
The eagle-owl, called that because of its size, has no natural predators.
It eats a lot of different thing Among them is the fox.
There are more foxes than eagle- Don't forget the last level, tho Decomposers.
Eventually, all these living things will die and become nutrients for plants.
And the cycle will start again.
Now, I want to point out that th that constant movement of energy between living organisms isn't the only cycle that is taking place in the biosphere?
The air we breathe is mostly made up of nitrogen.
This element is constantly circu through the atmosphere, geospher and the living organisms of the through the nitrogen cycle.
Likewise, carbon, another element essentia is also moving constantly throug the atmosphere, the geosphere, and the biosphere.
Energy cycles, nitrogen cycles, carbon cycles.
You know, life is pretty amazing and the way it's supported by cy they move energy through living organisms over and over.
It's just one of the many ways it is so amazing.
I love words.
'Cause words we people use have real power.
They have the power to hurt.
They have the power to heal.
They have the power to make some They have the power to make someone squeal with delight.
They have the power to make others think deeply.
Wise people have two rules for the words in their lives.
Rule number one, wise people pay really close att to the things they say.
Even when they are trying to tell the truth, they try to be kind and helpful and never be mean with words.
Rule number two, wise people take less offense to the words others use.
If someone says something mean to you or about you, just let it go.
It was mean, but it's just words It's not you.
Wise people control the words th and they control the way other people's words affect them.
Be wise.
Use your words well.
Magic is creating the illusion that you can defy the laws of na (bright music) - Magic is creating the illusion that you can defy the laws of na - Science is the study of how the natural world works.
This is science.
(bright music) What is science?
What is it really?
Sometimes I say science is the study of how the natural world works.
This is true, but it's so much more interesting than that.
Science is a way of thinking.
Science is a way of asking questions about the universe.
Science is a way of asking good about the things we see happenin in the natural world around us.
And most important of all, science is about getting really good truthful answers to those questions.
Science is a way or a process of getting answers to those ques that get as close as possible to the truth as we can.
Even if you are not a scientist, science matters to you and it matters to me.
How come?
Well, first of all, what if you have yummy peanut bu and a really lovely apple?
I'm going to eat them for lunch.
But what if I decide to throw the apple up in the air?
What happens?
It goes up and then it comes bac Why doesn't it just keep going up and up and up and up?
This is a very good question and thanks to science, we know t The answer is gravity.
Gravity.
Gravity is the force by which a planet draws objects towards its center.
What?
Yeah.
Gravity is the force.
In this case, earth that draws objects towards its center.
Yeah.
The apple that's falling d is falling towards the center of the earth.
Weird, right?
Down is towards the center of the earth, but it's true.
And how do we know this is true?
Because of science and because of lots of scientists.
Large, large, large, large numbers of scientists have tested the idea of gravity.
Then other large, large, large numbers of scientists have come along and said, hey, wait a minute, that's a goofy idea.
A force drawing objects towards the center of the planet?
I think I'll test that idea.
And then they test it too.
And then even more scientists co and they test it too.
And then even more scientists co and they test it even more.
After a whole ton of scientists have tested the idea of gravity, they come to the same conclusion They reach consensus.
They agree.
It's not just two or three scientists that agree, it's a lot.
It's hundreds or thousands or millions of scientists that have tested the idea themse and come to the same conclusion.
So, we know that gravity is the that draws objects towards its c We know this.
Thanks to science and to lots of scientists science is way more than just a cool collection of facts.
The sun is 93 million miles away from the earth.
The tadpole is a baby frog.
Humans are mostly made of water.
Science is actually a way of thi Science is a way of skeptically examining the universe.
Science is a way of skeptically looking at things that happen around us and reaching more accurate conclusions about those things.
Even if you don't want to be a scientist when you grow up, knowing how the world around you is super duper important.
Because you and I, we live in a world built by scie We get to cool our homes on hot days by air conditioning.
Thanks to science.
We get to watch hilarious videos on our favorite screens.
Thanks to science.
We get to recharge our game syst just by plugging them into the w That's also thanks to science.
You and I live in a world built by science.
So, this means scientific litera or understanding science and how is really important for making wise decisions about everything from how we sta how we keep the planet healthy to how we keep our pets healthy.
So, science isn't just for scientists, it's for everyone.
Humans have always wanted to explain the world around us.
Our ancestors often attributed natural events like illnesses, storms, or famin to the work of supernatural forces or even magic.
This was wrong.
This mostly happened because we are really, really, really good at noticing patterns.
We humans are pattern noticers.
Sometimes, however, the patterns are poor explanations for what is really happening in the world around us.
Even when the patterns we notice are not real or are poor explanations of the world around us, we can easily jump to incorrect conclusions because the pattern feels real.
Our perception, what we see and is based on our biases, emotions, expectations, experiences, and desires.
While the human brain is capable of really astonishing levels of it's also remarkably prone to errors or misperception.
The human mind makes lots of ass and we assume these are correct.
Take a look at these two tables.
Which table is longer?
The one on the left or the one on the right?
Yep.
I'd say the one on the left is for sure longer.
It looks longer, and I always believe what I see.
Seeing is believing, isn't it?
Or is it?
The table on the left is not actually longer.
The two tables are the same leng I'll show you.
- Oh, wow.
- This is an illusion devised by Franz Carl M üller-Lyer, a German sociologist.
He created it way back in 1889.
Here's another tricky illusion created by M üller-Lyer.
Which line is longer?
- Hmm?
- Yeah.
Obviously the one on the right is longer.
Actually, that's not true.
It's another illusion.
I'll measure just to make sure.
- Mm hm Ah-huh.
- See, they are the same size but that's not what your mind to and that is the beauty of scienc We can't just use one observation to draw a conclusion In this case, our vision, we need to test it.
We need to measure it.
I measure, and yep, they are the same size.
That's the beauty of science or the scientific method or the scientific way of thinkin Scientists don't accept their first thought, they test it.
You don't accept your first thought either.
You test it too.
Science is the best way we know to keep from fooling ourselves.
Science is designed to correct for our limited perceptions and flawed thinking.
Individual scientists try to be as objective as possible.
They're still human and they are prone to the exact same errors as the rest of us.
The thing that makes science so is that a claim is never evaluated by just one scientist.
It's evaluated or checked out or studied or tested by dozens or even hundreds of ex All these scientists are trying to find the flaws in each other's work.
It's how scientists think.
My brother is a scientist.
When we were kids, he'd watch my magic tricks very closely and if you saw how the trick was he'd shout out, "I know how you did that.
It's in the other hand."
Scientists are naturally skeptic It's how their minds work.
Scientists want to know the trut and they are skeptical of claims people make.
They are even skeptical of other scientists.
They look for a hole in a theory They go looking for the incorrect reading or conclusion.
When they look and look and look and don't find anything wrong, they say, yep, that sounds good It's good science.
Science's secret sauce is that claims are never evaluated by just one scientist, but dozens or hundreds of expert It's important to understand that science makes three assumpt Seeing the world and understanding the world through the lens of science means you make these three assum First, the process of science assumes the world is real.
You and I tend to see the world in different ways.
We've lived at different places, we've gone to different schools, we've had different friends, so we tend to see the world very differently.
But scientists know there is an objective reality that exists outside of our experiences, outside our heads.
So, first, science says, hey, the world is real.
Second, scientists believe it's possible to understand that objective world outside our heads.
It's outside our heads.
It's real.
By using the tools of science, it's methods, it's it's thinking, it's processes, by using science, we can explain and understand the natural world around us.
Third, and lastly, science assumes we can explain w in the natural world with natural processes.
We do not say, oh, it was just m Unless you're a magician, of cou and you're doing a magic trick, pretending to defy the laws of n Science is good, even very good at answering ques but it doesn't have to answer ev Science is limited to what it ca and potentially falsify, which means that evidence must be observable, measurable, and, repeatable.
Observable, measurable, repeatab Evidence must be observable, measurable, repeatable.
For example, science can't answer personal questions like, what's your favorite color Or is it wrong to steal?
Yes, it is wrong to steal, but that's not science.
That's just you being a good hum The goal of scientific knowledge is to understand and explain the natural world.
Is the pattern we've observed re And one of science's greatest st is that it has the humility to r that we can never be completely Scientific knowledge is tentativ Science doesn't prove it reduces uncertainty.
Science is the most reliable met for understanding objective real And the cool thing about science it's open to people of every col shape, size, or religion.
But here's the weird thing about because it recognizes and correc for our individual limitations a Finding consensus among scientis is sometimes really hard because each scientist is incent to find flaws or limitations in other scientist's work.
But claims that withstand the collective scrutiny of the scientific community become acts, models, laws, and t that are used to further expand the body of knowledge, and that is a really good thing.
Science created the modern world we live in.
It touches every aspect of our l from our health to the environme And the key to making good decis in our modern science created wo is scientific literacy.
Knowing what science really is.
Science is a way of thinking.
Science is a way of asking questions about the universe.
Science is a way of asking good about the things we see happenin in the natural world around us.
And most of all, science is about getting really truthful answers to those questi that get as close as possible to the truth as we can.
Yeah, science totally rocks.
(rock music) - And now, something silly.
(whimsical music) (whimsical music continues) (upbeat music) - Biologically, chemically, atom everything is connected.
(upbeat music) (upbeat music continues) - Major funding for this program provided by Jason Isbell and Amanda Shires.
Keep Alabama beautiful and Northrop Grumman.
♪ Yes the ocean is deep ♪ ♪ And the sky is so high ♪ ♪ And the earth is so wide ♪ - It's a mystery but deep down everyone knows.

- Science and Nature

Explore scientific discoveries on television's most acclaimed science documentary series.

- Science and Nature

Capturing the splendor of the natural world, from the African plains to the Antarctic ice.












Support for PBS provided by:
Steve Trash Science is a local public television program presented by APT