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Course: Middle school biology - NGSS > Unit 4
Lesson 1: Populations, communities, and ecosystemsPopulations, communities, and ecosystems
Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. Created by Sal Khan.
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- I wonder what would happen if we could understand animals(14 votes)
- we would have a harder time finding a pet if they had a opinion.(31 votes)
- cant the prey defeat the predator(10 votes)
- The name "prey" is given to those who are more likely to be eaten by another animal (e.x. a wolf and a rabbit, the rabbit is the prey). But, it is possible for multiple rabbits to attack the wolf, just not likely. Hoped this helped!(21 votes)
- hey I see a little pink fish(16 votes)
- if he thinks those are ellephents, his eyes are broken.(10 votes)
- cant preys defeat the predator(5 votes)
- They cannot because the predator is the one who is stronger and trying to kill and eat the prey.(2 votes)
- Hello Everyone!
I need a bit of help understanding communities. What I don´t understand is, is a community the group of ALL living organisms in an area, or just a specific ones?
Thanks for any answers :)(6 votes)- the community is a group of many populations(3 votes)
- how much oxygen in a the water?(3 votes)
- Living organisms in lakes, rivers, streams, and oceans need oxygen to survive therefore dissolved oxygen is essential in an aquatic environment but unfortunately, it is not very abundant. While air consists of 21% oxygen, the oxygen content in water is only 0.001%!(3 votes)
- why do people posion the ocean(4 votes)
- We do that because we are at “the top of the food chain”. Many of us need coal, oil, and many more other things that come from oceans. We disturb the natural environment, such as causing oil spills, which take a lot of time and effort to clean up, and we still won’t clean all of it up. We can try to reduce poisoning of the ocean though. Many people become aware about ocean health.
-π(5 votes)
- is coral truly a living thing? if so what do they give? or eat?(2 votes)
- Coral is in fact a living thing however it is more related to a plant than anything else. They give sea life oxygen and they infect do not eat anything but instead get there energy from the sun.(1 vote)
- question,do plants go under the communities(4 votes)
- Yes beacause they can(3 votes)
Video transcript
- [Instructor] In biology, it's useful to have some shared language so we can communicate and
describe the world around us in ways that we can all
understand together. So here, we're going to
talk about populations, communities, and ecosystems. And as we will see, these
are all related ideas. So first of all, a population
is talking about the members of a specific species in an area. So for example, in this picture, we have a population of zebra. I have one zebra there, one zebra there, there might be some
others that we can't see. In fact, there are likely to be. So, these are each members
of a population of zebra. Now, we have other
populations in this picture. We have a population of buffalo. These three are members
of that population. We have a population of antelope. In fact, there is a bunch
of antelope in this picture. So, we have many members
of that population. We even see some animals
here in the background. I can't quite make out what they are, but that could be a different population. Let's say if those are elephants, they might be elephants
the way I see them, but that could be members of
a population of elephants. So if that is a population,
what is a community? Well, a community is all
of the living species that live in the same area. So, we have a community of animals that is made up of populations of buffalo, of zebra, and of antelope. And I wanna make clear
that the populations or when we're talking
about the communities, we're not necessarily just talking about large animals like this. We could be talking about
populations of mosquitoes. We could be talking about
populations of fish in this pond, if there are any fish. We could have a population of
a certain species of plant. And likewise, when we're
talking about communities, we're talking about collectively all of the living organisms together. Now, last but not least, what
would be an ecosystem then? Well, an ecosystem is all
of the living organisms plus all of the non-living things. So, the ecosystem that we see here would also include the water, it would also include the dirt, it would also include the air. And organisms like those
that we see right here are constantly interacting
with both the living and nonliving parts of their environment. These interactions are
how organisms get food, shelter, water, and warmth. These interactions are
how organisms survive and produce offspring. So, let's get a little bit more practice with this idea of populations,
communities, and ecosystems. And we will do that by
looking at this picture right over here. Pause this video and think about what are the populations here? Well, you might not know the name of all these different types of fish, but you can see that there's a population of this gold-colored fish right over here. There's also another population
of this blue-colored fish. We could keep looking
for other populations. It looks like there's a
population of this silver-colored or I guess long-ish silver
fish right over here. But once again, it's not just the fish. There's a population of coral, there's populations of microorganisms that we can't see here. The community would be all
of these living organisms that live close to each other. And we'll see, sometimes
they compete with each other, sometimes they eat each other, but sometimes they help each other, Or sometimes they don't matter
that much to each other. And we'll study that in a lot more detail. And then the ecosystem
includes all of the above plus the water, plus the
oxygen that is in the water, plus the sand at the bottom of the ocean. So, I'll leave you there. Hopefully, you now have a sense of what biologists are talking about when they talk about populations, communities, and ecosystems.