If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:7:33
AP.ENVSCI:
ERT‑1 (EU)
,
ERT‑1.B (LO)
,
ERT‑1.B.1 (EK)
,
ERT‑1.B.2 (EK)
,
ERT‑1.B.3 (EK)

Video transcript

so just as a bit of a review if we take the members of a certain species that share the same area we call that a population population all of the organisms in this particular population will be members of the same species there could be other members of that species that aren't in that same area and they wouldn't be a member of this particular population and a certain area won't have just one or doesn't tend to have just one species in it so we could call this population one you might have other populations there of a different species so this is another species right over here all of them combined in the same area we could call this population population too and if you take and we could obviously have many more populations there if you take all of the populations in a given area and you could there's flexibility on how you define that area or define that region you take those together so you're really taking all of the living things in a certain area we call that community the community of populations now the community only consists of living things the biotic factors so let me write that down biotic biotic referring to the living things in a certain area but if we want to think about not just the living things but also the nonliving things in that region so I'll write a biotic let me do that in another color so let's take out let's take the abiotic factors or the abiotic environment and once again we're sharing the same region and that is flexible on how you define that region you put all of these things together and then you get your ecosystem your ecosystem once again it could be a very small region it could be a very large region but it's made up of all the living things the biotic factors and the nonliving things the abiotic factors now what we're going to think about in this video is just the types of ecosystems that you might have think a little bit about it and also begin to think about how the different factors interact with each other how there's a conservation of matter we're within an ecosystem matter tends to go from one form to another you also have a flow of energy energy tends to enter an ecosystem in form of light and that energy gets transferred from one organism to another and sometimes even involving the nonliving things eventually becoming getting turned into actual heat now in terms of the types of ecosystems I already mentioned there's a lot of variety there this right here is a picture of a tide pool at Half Moon Bay not too far from where I live I've actually been to the tide pools at Half Moon Bay and you could consider one particular tide pool in both the abiotic factors the water and and the rock there as long as as well as the biotic factors the starfish the the sea anemones and and and whatever else might be living there those combined that could be an ecosystem you might get to say that the entire beach is an ecosystem you might say that the entire region is an ecosystem once again it depends on on how much you want to zoom in or how much you want to zoom out and you can zoom out a good bit this rainforest right over here this is the Amazon rainforest you can consider the whole rainforest an ecosystem or maybe you just want to study maybe you just want to study what's happening in this exact region right over there you could also consider that an ecosystem you can consider what's happening in the river itself an ecosystem or maybe one part of that river and as you notice I'm talking about some ecosystems that are on land and some that are in water and that is a general way of one way of classifying them so an ecosystem you could have it on land you could have it on near in the water so we could say it's aquatic and then even within aquatic you can have ones that you have saltwater or partially salty water and these are called marine and the main marine ecosystem we're thinking about the oceans and and things like that and then you have freshwater ecosystems like if you are in the upper Amazon that is fresh water that is flowing so we could say fresh freshwater non non salty water and even though it looks like rivers are big and there's a lot of freshwater around us obviously we need fresh water to live most of the aquatic ecosystems are marine are not involved fresh water fresh water is a very small subset now this is just a few examples even your body.you you could view your body as a whole as any system you could view parts of your bodies and ecosystem you could look at just you could look at just a fraction of if this is my hand right over here you could just take a little square there and you can consider that an ecosystem and you can think about the different bacteria that are there other types of microorganisms that are there and how they are interacting with the nonliving things the the air how they are interacting with the oil on your skin with the dead skin cells and also how they're interacting with the living skin cells and you yourself now since we're in the since we're in the we're focused on how we can classify ecosystems one thing that's often done is classifying land ecosystems into various categories and right over here we have depicted the major types of land ecosystems in on our on our planet and where you might find them and these different types of land ecosystems these are called biomes biomes and as you can see from this diagram tropical forests you could find it right over here thus Amazon rainforest you can find it in Africa you can find it in Southeast Asia you can find it in in Central and even southern North America you have boreal forests which you'll find in more northern latitude Savannah desert tundra Chaperone polarize temperate forests temperate grasslands and these are just helpful for thinking about roughly the types of ecosystem or ecosystems we would find in those regions and it's typically most determined by temperature moisture the climate but actually the climate and the terrain and the types of minerals that you would find there that tends to be a pretty good indicator for what it will be like what the life would be like but even with that said there could still be a lot of variety for example the Sonoran Desert that is right over here in the southwest United States in the northwest Mexico this is a desert and it's there and there's deserts all over the rest of the planet but they won't have they might be similar in a lot of ways but they won't have the exact same climate or the exact same abiotic factors are the exact same biotic factors so for example right now I'm going to show you picture pictures of the Sonoran desert and the rock desert that's on the island of boa vista boa vista is right over there you really can't see it's a very small island off the coast of Africa and as we see in these diagram or in this picture you don't have to be an expert to recognize that okay these are both deserts they both look dry there's not a lot of water here but they are also very different the Sonoran Desert looks to have at least a lot more life than the rock desert have here it's appropriately named the rock desert because it seems at least to the naked eye it looks like all you can see is rock so biomes once again it's a very rough high-level way of classifying land ecosystems but even though the same biome can be very very the two things that are categorized in the same biome could be very different
Biology is brought to you with support from the Amgen Foundation