Hi. It’s Mr. Andersen and this is environmental
science video 8. It is on energy flow in ecosystems. In the last video we talked about the importance
of producers producing food that is consumed by consumers. But we did not talk about where
that energy comes from. What is the major energy source on our planet? It is going to
be the sun. And this model also does not show that we are losing energy to heat at each
step along the way. And so a better model is an ecological pyramid that looks like this.
And so the producers on our planet produce food, make energy usable. Where did that energy
originally come from? It came from either the sun or chemicals. And so all plants do
photosynthesis and so they are taking energy from the sun and putting it into the energy
of the bonds of the food. Now some chemosynthetic bacteria can do the same thing with chemicals,
like hydrogen sulfide. They are making that energy usable. Now once they have made that
energy usable they can respire it. And so can all of the consumers that sit above or
below them on this trophic level. Now we measure this amount of energy that is converted through
productivity in one of two ways. Either gross primary productivity or net primary productivity.
Gross is the overall amount of energy converted and net is just how much the plant gets after
it uses some of the energy for respiration. Now each of the levels within this food chain
are going to be a trophic level. And we are losing energy along the way and so a good
way to measure this is using an ecological pyramid. We can measure the efficiency, in
other words how much energy makes it to the next level. We can measure the energy at each
level or we could measure the biomass, how much living material do we have. And so energetics
is the study of how energy gets from something like the sun into organisms. What is the most
important first step is going to be photosynthesis. In photosynthesis we take carbon dioxide in
the air, water, and energy and sunlight and we convert that into oxygen and glucose. If
you have not memorized the equation for photosynthesis now is the time to do it. You should know
what is going into the reaction and what is coming out of the reaction. And why that is
important is we can simply turn the arrow around and now we have the equation for cellular
respiration. So that is what you are doing. You are taking in the oxygen that is produced
by plants, taking in the sugar and you are converting that into carbon dioxide and water.
The nice thing is that this can be recycled again back into plants. And so this is really
how we take energy, put it in plants, store it in the food so we can utilize it as well.
Now one major misconception is that plants are doing respiration as well. They are making
the sugar for themselves to release that energy. Now something very similar to photosynthesis
is called chemosynthesis. And so if we look down deep in the oceans at these hydrothermal
vents we are producing not only heat but we are producing a chemical called hydrogen sulfide.
Also methane can be used this was. And so certain chemosynthetic bacteria, look how
similar this is to photosynthesis, can use the energy in the bonds of the hydrogen sulfide
to make glucose. They release water and then sulfur. And so the equation looks very similar
to photosynthesis. Now what happens is things living around the chemosynthetic bacteria
can take in that glucose and they can use oxygen to do cellular respiration. And so
we have a totally different system. It is built on the energy inside the chemicals.
So no matter where the energy comes from we can measure the amount that gets into the
producers using productivity. Now the bad news is that hardly any of that energy actually
gets into the plant. Ninety-nine percent is going to move through it, bounce off of it.
The plant does not get it. Only one percent actually goes into the producer and we call
that the gross primary productivity. It is the amount of energy that the plant actually
gets. Now what is the plant going to do? It has to survive. And so it is doing respiration.
That is where most of the energy goes. And a small percent of it goes to what is called
the net primary productivity. That is the amount the plant gets if we subtract the amount
that it used for respiration. So the bad news, not much energy goes into the producers. What
is the good news? There is so much energy contained within the sun. If we look at the
productivity on our planet we could compare different terrestrial and aquatic biomes all
the way from the tropical rainforest which has high productivity. We are measuring that
as the amount of material per meter squared per year all the way down to something like
a desert. It is not very productive at all. What is interesting is cultivated land actually
does not produce that much. We could compare that to aquatic systems like coral reefs which
are incredibly productive. We could even look at how it changes over time. So this is net
primary productivity. So this is terrestrial, on land. And watch what happens as it changes
over an eleven year period of time. You could see that is just moving back and forth. It
is moving from the southern hemisphere to the northern hemisphere. You can see there
is no production in areas where we have massive deserts. But what is causing that change?
It is simply going to be the seasons. During the summer we are going to have way more production
where there is way more sunlight. And so an accurate model of measuring how energy is
used is an ecological pyramid like this. And so what we are really looking at here is the
net primary productivity, the amount at this level. And so if we start here with the producers,
let’s say that that small percent is actually one hundred percent, what percent goes to
the next level? Well we are losing energy at each level. And that is because the organism
has to survive. It does respiration so we are losing heat at each level. And so in general,
of the one hundred percent that the producers get only ten percent goes to the next level.
What percent of this goes to the next level? Ten percent of that. So now we are down to
one percent. And what about the next level? Ten percent of that. And so we are losing
a huge amount of energy at each step along the way. And that is going to be why we have
way less tertiary consumers then we are going to have producers in an area. A good way to
study this is using an energy pyramid. And let’s look at an actual energy pyramid from
Silver Springs Florida. What we are looking here is the amount of energy. They are measuring
it in kilocals per meter squared per year. And so it is 20,000 kilocals. Now where is
the energy found? Just looking at this picture it is going to be for the most part in these
trees. What amount makes it to the next level to the consumers? Well when they studied it,
it was this amount. So what is the ecological efficiency? What amount made it to the next
level? Well you could just take this and divide it by that. And we could find that sixteen
percent moved to the next level. We could look at the secondary consumers. You can see
it is around ten percent there. And we could look at the tertiary consumers and you can
see that it is around five percent. And so ecological efficiency is going to be somewhere
between five and twenty percent depending on how efficient that ecosystem is. Now what
are we really missing on this energy diagram are the decomposers. They are going to make
use of a lot of the energy as well. Another way to measure it is biomass. Just how much
material is made. What is different here that we do not measure it over a given period of
time. We measure what is called standing crop. It is the amount that is there at one point
in time. But you can see the same thing occurs if we are looking at a Wisconsin lake or a
field or a coral reef the amount of biomass that we have at the producer level is going
to be way more than what we have at the levels above it. And so did you learn the following.
Can you fill in all the blanks? Pause the video. If not I would say the energy comes
from chemicals through chemosynthesis to producers. We could measure productivity as gross or
net primary productivity. How do we utilize that energy? This would be respiration all
the way down to heat. We then have the trophic levels. Those are going to be the feeding
levels. Ecological pyramids measure efficiency. And we can also measure the biomass. And I
hope that was helpful.
So can we conclude that if the human population becomes vegetarian then as secondary consumers (rather than tertiary) there will be more energy to sustain a growing world populations?
Thank you soo much!!!!
Why do biologists have to give these really important chemicals such gayass names as ATP or whatever… You know if it was a story, or an mmorpg, or a religion they'd call it something cool like life-essence or carnanimus, or mana.
THANK YOU MR ANDERSON
wow .. thank u that was pretty helpful
wow .. thank u that was pretty helpful
Just a simple question. Why do some animals, such as birds and alligators, help each other by the bird cleaning the alligators teeth and the alligator not eating the bird? I never understood that.
That was helpful. I have few questions though i would like to know more about urban ecology or may be urban ecosystem
Very helpful!
Hello
That was so fast. Did he actually breathe in between?
Very well explained and very helpfull too!! Good Video
2:30 This one took me a good minute to sort out for myself even though it took you only 7 seconds to say it. "Misconception"? I think you mean "Something not often known." You use that word but immediately go on to explain the right idea, which is exclusively the opposite of a misconception. You might understand my confusion? As a listener, when I hear a setup like "One misconception is," I expect the misconception to be stated, and a correction to be stated. It's subconscious.
Maybe I'm nitpicking, but this has the potential to be a problem.
The change in subject came as a surprise. I felt like I was left with a cliffhanger, so my attention was adrift as the lecture continued.
Many listeners may smooth over their critical thinking when they hear something that dissonant. I mean that they may just make an arbitrary decision on the fly as to what you meant without stopping to think so they won't miss anything. I wonder if a significant fraction of listeners will remember plants as NOT doing cell respiration since that's what anticipation would first determine.
Thanks for following up with the clarifying sentence at 2:33 or I would have been misinformed rather than momentarily confused.
Dude! Maybe slow down a bit or give us the same meds you are taking? What about the energy of geothermal? It is quite small compared to the chemical energy and our sun but does it not make contributions worth mentioning? Thanks for the video. Well done and appreciated.
too fast bro
it was helpful but too fast bruh
A real quick thing I want to add, the energy pyramid. There is a role of the 2nd law of thermodynamics, "energy does not diminish, but the ability to use it does." Something like that, that's why you see only 10% of the energy being passed down, due to respiration taking most of it and keep in mind of that law.
I was forced to come here by my teacher…
How much energy is taken form the sun by plants
I l like it
this is complacated
SOOOOO INFORMITIVE !!!
I came here from science class!
if u look at him from your peripheral vision all of a sudden it feels like his head is floating in space
For all those people complaining about how he was going too fast, there is a pause button guys! I paused the video a few times myself
It is very use ful but you necedad to Talmud slowest
Oh wow you hit 100,000 views π congrats! So helpful π
school? anyone
ur a nub
great video , sir :))
Thank you, so much.Β Can you tell me about what food we can eat that balance our human Ecosytems
thnk youuuu. it's really helpful!
If the pyramid of biomass in aquatic ecosystem is inverted then how can higher tropic level organisms get the energy if only 10% is sent in higher tropic level. PLEASE HELP!
Why only 10%?
It was a good video everyone just stop complaining.
if you think its too fast, just slow down the speed????
If you think he is going too fast, then you are just too slow to process what he is talking about.
I have a Biology test next Tuesday, and you summed up all the 9th grade 3rd season material that is included in this test, I understand everything now π thx
At 4:06 you talk about total productivity by ecosystem. What are your resources please? Google hasn't yielded very good results for me.
Also, do you know of any data on efficiency of ecosystems? E.g. the desert might be less productive (lower volume of digestible calories) than the forest, but it could be more efficient than the forest at producing those calories.
Lastly, "cultivated land" is an average. It fails to distinguish between types of cultivated lands. In some deserts ponds made by drilling into an aquifer attracts animals, which then thrive.
super
not really so fast
You really are such a good teacher. Clear, pleasant and good at using models and examples that are easy to understand. Great job!
Thanks
Boring use easy language bro and slow
To fast for me, I get it.
Very helpful for my 9th std exam which is tomorrow. But try to slow down
So incredibly helpful thank you
i just watched this in class!!! im still in class!!!
Turn on subtitles and slow down the video to 0.75 or 0.5 if it is too fast for you.
Good video. Watched it in class.
Who else is here the day before an exam
Itβs very helpful thank you Man U r very nice
Very helpful Thank you ma teacher βΊπ
what a big head…….
thanks
Thank you so much! Your video's are very helpfull and clear!
cheers bro but way too fast
hi nerds
That was helpful. When you say that there is a common misconception that plants respire, do you mean it is a misconception that plants respire with byproducts of CO2 and H2O? Because later on in the video, you said plants use about 60% of energy through respiration.
Best
Thank you!! So clear! Now I understand everything π
Perfect brief explanation for my upcoming exam!!
please use some Hindi not because I don't understand just because it makes easy and good way of teaching
Can some one answers my question please if the primary producers aka plants have the most energy how come they have less calories than tertiary consumers? My theory is that these animals are constantly eating therefore they create their fat reserves piling up energy aka calories
I have never been so in love with a man
asdsadsadasdasdsadasdasdsadsads
this helps sooooooooo much
College senior level ecology is harder than i thought. i was hoping it would be like animal planet lol
Chad faced John green
Love silver springs! Love your videos!
No
idiot
Can I die yet?
thank you so much
So would it be more efficient (energy wise) to eat a cow then rather eating a lion?
Wow! The Video Help me a lot sir . Thanks for making an Perfect video for me cause I have an Lesson relate to this in my Biology book . Thanks for this Video .
Very helpful
Thanks man. For the people who are complaining its too fast, just turn on subtitles and turn the video speed down to like 0.75 or 0.5. Jeez like srsly guys. Stop being so bloodsucking.
I shall bet that if Alexander Graham Bell, Wright Brothers, and Edison to name just a couple would have a very hard time with ecosystems just look what they did 1 person did for mankind benefit. No structures at all.
That video is very interesting and i have learned too many things from these
no
I love ur teaching style …I m glad I found Ur videos…thanks Mann..
Nice Vid
did not understand one thing
Stfu
No it was shittt
whhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhy is this guy so booooooooooooooooooooooooooooooooooooooooooooooooring
fuck u mother fucker bich ass hole
Thanks for this video super
Best voice ever
Thank you really much for everything you teach! You are so good π
Fagot
Sub to keipert labs
I love Hector
i love Adriana
Oh yes
Sorry but you talk to fast plz slow down for me plz, thx
for ayone at k12 who needs the times for the questions here u go. 0:20 , 0:51
1:03 2:19 3:13 3:36 4:53 5:23 5:43 6:31 . hope this helps π
Yeoo I have a science test on this tmrw so this helpedπ
Very helpful
Ur a poopy head
Wait i have a question. So we have the 10 percent law by leinderman…so as there is a 10% loss of energy along the trophic level…so vegeterians more energy efficient than non vegeterians ? So is it better to be a vegeterian ?
hey fellow bozeite