Transcript for:
Understanding Ecological Niches and Adaptations

What's up everybody! So in this video we're gonna be talking about ecological niches. Finally the day has come!

Man but before we even start guys go check out teachme.org right if you want beautiful sexy notes with lots of IB style questions. Now anyways sit back relax there's a lot of stuff to talk about in this video where we're gonna cover everything that you could possibly need to know for B4.2 so let's just get started guys. So we need to know The topic is ecological niches, so it'd be helpful to know what ecology means. Ecology is a broad term, and it is basically the study of the relationships between living organisms and their physical environment. Hmm, so let's take this earth.

We know earth has a lot of different physical environments. For example, let's start here with down here, southern Africa, Cape Town, okay, a little city, a lot of buildings, a lot of stadiums, maybe mountains, right? The environment's pretty interesting there.

Now because of that environment, there will be certain organisms that are gonna live there because they're suited, they're adapted for that environment and those organisms are mainly humans like me and you. Well if we pick this area here, the ocean, it's different. It's mainly water, maybe some aquatic plants, maybe some aquatic animals like these crazy looking fish here, right?

The environment's different. Because the environment is different, we need different organisms that are adapted, that are suited to live in that environment, right? What about here?

North Africa, it's like a desert, right? Only crazy things can live there. What about here?

Like Canada or Finland, whatever. Some place in Europe look like this. Only some crazy people can live in this kind of cool place, right? So anyways, you can see that we have so many different physical environments and corresponding those physical environments, we have certain organisms that live there because they are suited, they're adapted to survive and thrive in those conditions, right? So ecology is the study of these living organisms.

and their relationship with their physical environment. How they survive, how they're adapted, what they eat, who they interact with. That's ecology in a nutshell.

Now when we learn about ecology, there's very a lot of key kind of words we need to know for everything to make a lot of sense. These four are very important. Species, population, community, ecosystem. And we're going to talk about these four now first. Starting from species, then population, then community, and then ecosystem.

Because in this order, They make a lot of sense. They're so easy to understand. So look at this environment, right?

This is just another environment on Earth. And this one is from Lion King, right? The movie.

If you haven't watched it, watch it. I like the cartoon version much better, but anyway, that's off topic. We know, you can tell me right now, I know that this lion and this giraffe, they're different species. Okay, but I can ask you why? Why?

Why are they not the same species? Because the definition of species is a group of organisms that can interbreed. and produce fertile offspring.

This lion and this giraffe, if they try and have kids, they will not be able to and even if they can, their offspring will be infertile. Meaning infertile means they cannot have their own kids. Okay, so to be the same species, two organisms must be able to interbreed to produce fertile offspring. For example, one lion with another lion, they will make an offspring and that offspring will be fertile, meaning that offspring, that lion, cub, will be able to make their own kids. By that logic the two lions are the same species, okay?

And the lion and the giraffe are not the same species. So make sure you understand that. Now if you understand species, population is going to make a lot of sense. Because a population is just a group of the same species. It's a group of organisms of the same species who live in at the...

who live in... I cannot write sentences to save my life, so let me fix this. a group of organisms of the same species who live in the same area at the same time. So if you understand species, a population is just a bunch of those species. So if we have this is one lion, so it's a species.

If we have a group of lions, that's a population of lions. Okay, very very straightforward. If you understand population, community is also easy.

A community is a bunch of different populations in the same area. So it's a group of populations living and interacting with each other in an area. So if you look at this picture here, These giraffes right here, that's a population because they're the groups of the same species who live in the area at the same time. If we take this whole image, that's a community because there's different populations, a population of giraffes, population of elephants, populations of buffaloes, zebras.

That's a community. OK, a group of populations together. OK, like I like I said before, I urge you to remember these definitions as close as you can word by word, because they try and make it so tricky on test by changing one word here and there and then you get confused.

OK. So this is one of those rare times where I will tell you to try and remember it word by word, okay? I don't like to normally do that because I want you guys to understand it, not memorize it. But this is maybe one of those times I'd recommend you. Okay, cool.

Now if you get community, ecosystem is even easier. It's a community and it's abiotic environment, right? A community is a bunch of living organisms, right?

Like we said. And so an ecosystem is a community, all those living organisms, and the abiotic environment. Biotic means living.

Abiotic means non-living. So community would be considered biotic because all the living organisms including plants all the animals right that's the community. The abiotic environment is the non-living components. So what in this picture is considered non-living?

Think about it. Sunlight. Maybe this rock, maybe soil, maybe water.

All of those are abiotic things. I can put it here for you guys. So a community, an ecosystem is a community and the abiotic, the non-living factors associated with it.

A lot of students get confused and think that these mountains, these trees, these grass, they are abiotic. But remember plants are living, they're made up of plant cells. So don't confuse plants and trees with the abiotic environment.

Abiotic must be non-living. It must be rocks and things like that, non-living things, okay? Okay, that's key. So make sure you know these four definitions. They most likely will come up, I promise you.

Now that we're done with that, oh yeah, just about these. So you can imagine these different environments will have different abiotic factors. For example, sunlight may be very present here in the desert and very rare here underwater. Maybe the water here is very cold, maybe the water, I mean, maybe the water here is freezing, maybe the water here is warmer.

Okay, so the abiotic factors can vary from environment to environment. That's why it's important to know about. Okay, now we got to learn about niche. So when I first learned niche, I really associated with like expensive rare things like Gucci.

Okay, like certain brands. But actually in ecology, niche is different. Okay, in ecology, niche means the unique role that a species plays in a community and where the organism lives.

Okay, so two components. The job. the role that an organism plays and where it lives, the habitat. Okay, that's what niche means.

Now me and you, our job, we have different jobs. I might be teaching you right now, you may be going to school right now, you may be a businessman, you may be a football player, whatever. We humans have different kind of jobs. Now these lions, they can't do desk work and stuff like that.

So their job is basically consisting of what they eat, and what interactions they have with other organisms. So a lion's job may be to be a vicious predator, to scare off all the antelopes and eat antelopes or eat the freshly born warthog or whatever, right? That's their job, their role in the community, okay?

Now their habitat would be the area where they live in, right? Now a habitat is consistent of two things. The biotic, so the living aspect of the environment, so the trees and all that sort of stuff.

and the abiotic aspect of the habitat such as the rocks, the sunlight and those kind of things so habitat is the environment where you live which comprises biotic and abiotic things okay now remember the niche two things the job and where you live that's a niche now there's two words i want to quickly show you because you may hear them you might be confused i didn't know this one existed until i found out recently so extinct we know what that means i'm not going to say it it's when a species i'm going to say it i guess it's when a species dies out completely. So when this lion dies, it is not extinct, it is dead. When the whole species dies, it is extinct. When this lion dies, there's still other lions around, so the species is not extinct. So extinct only refers to when the entire species is wiped out.

Now extant is the antonym of extinct, the opposite word, okay? It means currently existing. So this lion is currently extant, it's existing.

I thought when I first saw this that it was a spelling mistake, but trust me, it's a real word. Okay, it's the opposite of extinct. Now, We need to know about two different kinds of niche. You know now what a niche is, the job and the habitat. Now, there are two kinds of niche, fundamental and realized niche.

Now, let's take an organism, a dog. The fundamental niche of this dog would be the area, the potential niche, the potential area that it could inhabit, given its adaptations and its tolerance limits. So basically, given its abilities and its toughness, given its tolerance, the area that it could inhabit. So we know a dog.

They have very good sense of smell. They're pretty wild. They can kill things if they wanted to. They're very, very special, right?

So technically, they could live in the forest, right? But we know they're also super cute. So we love them in our houses. So they can also live in a city. They can live in your house, right?

So this would be their fundamental niche, the potential area that something could actually inhibit given its adaptations and its tolerance limits. Now, a realized niche is different. This is the actual area. that this organism inhabits.

Even if it has many adaptations and it can live in the forest, where does it actually live? That's the realized niche. So you'll know that the realized niche is always much smaller than the fundamental niche.

So a dog's realized niche might be a city. Why is it? Why does something have a realized niche?

Because of certain factors like competition. Maybe when this dog goes into the forest it realizes wow there's a lot of bad things there it doesn't like, so it doesn't really like to go into the forest. Even though it could technically survive there, all the predators are maybe a bit scary for a dog, so they prefer not to go there. Or we put a leash on your dog to keep it close to you.

You have a fence around your house to keep the dog from running. away right so all of these little things like competition and little factors that influence the location that could make an organism have a realized niche okay that's i hope that makes sense so i use the dog because everyone knows dogs and this example is quite straightforward but there are the the book maybe we'll use another example but just know the concept that's the important part okay the difference between a fundamental niche and the realized niche okay awesome now Since we've been talking about niches, I need to ask you something real quick. Do you think two organisms, two species, can occupy the same exact niche?

No. And this was proven by the principle of competitive exclusion. Okay, this principle, and I'll show you now, states that no two species in a community can occupy the same niche, meaning no two species can have the exact same role and the exact same habitat. Okay, because there's only room for one species with that role and that habitat. And we'll see it, they did an experiment.

This guy, this Russian Ecologist did an experiment to show this and he used bacteria. Okay, we're gonna go quickly over this I don't think it's too crazy important. Look he took, you know these guys, these are petri dishes These little things used in labs, unless you become a doctor or some scientist, you probably won't see these. Now These are little dishes and inside the dishes you they will put these little medium this little liquid or or rubbery thing That contains nutrients and stuff like that, so food.

Okay, so you can see here what this scientist did is he took two bacteria Don't worry about their names. Okay, just understand the concept here. And he put them both into a separate petri dish.

Okay, and inside those petri dishes, there was food. This nutrient-rich fluid. Okay, so that these bacteria can survive. And then he waited.

So they're both in their separate thing. And after a while, they grew and grew and proliferated and became very full. So they're thriving in this environment. Then, guess what?

Then he took a separate petri dish. And he put both of them inside at the same time with the same nutrients. So it's the same environment as before.

These bacteria have the same job as before. They got to eat these food and they got to survive. They have the same role.

But now he noticed after time, only one survived. The other one died out. Okay.

So this shows that no two species in a community can occupy the same niche because one will take over and the other one will die. One will be more suited, more adapted for that specific niche than the other one, causing the other one to die out. So you can see why this little graph here with time and population.

The green one, when they were put in the same niche, the green one was able to grow and thrive, whereas the other one initially grew because the nutrients were there, but then when the other one grew and they started becoming very competitive, when there was competition between these two species, the blue ones started to fail. These green ones were taking over because they were more suited, more adapted. So we call this interspecific competition.

Inter means between. So between these species there was too much competition, and I'm proving this theory of competitive exclusion. that no two species in a community can occupy the same niche. And the reason why they use bacteria to show this and not like lions is because bacteria replicate very fast and die very fast.

So it's very easy to show in a short time span this effect, whereas for lions and humans, you'd have to wait hundreds of years to carry out an experiment like this. So they like using bacteria because it's very easy to show this result very quickly. Okay, so it's very basic. I want you to know this principle. And what I want you to take away is that Basically the conclusion is when two species have similar need for the same resources in the same space at the same time meaning basically The same niche the same niche one will be excluded Okay, because they will have they'll have too much competition and the one will become excluded because it's weaker than the other Okay, that's it.

Okay. I hope that makes sense. Okay Let's go back to your recap.

So we covered now all this stuff, keywords and ecology. We talked about all of these three things. We're going to go now into feeding and nutrition. We all love food. I mean, I'm a big food eater.

I love my candy, unfortunately. I don't know about you, but we're going to talk about this now. It's going to be interesting. Some food and nutrition and organisms.

So as a quick, I need to clear this up, okay? Remember on our planet, right? We have three big categories of organisms. Eukaryotes.

Archaea, the three domains, right? All organisms are grouped into one of these three domains So eukarya would include all organisms with eukaryotic cells like me and you, like plants, like fungi and then other organisms For example, bacteria will fall under this category or archaea will fall under this category, right? So these are prokaryotic cells. They're made up of slightly different cells.

So remember these prokaryotic organisms They are mostly single-celled organisms. So they're organisms that are only one cell Whereas eukaryotes can be both single-celled or multi-celled. Like look, there are some eukaryotes that are only one cell, but look, me and you, we're made up of many cells, so we are multi-celled. So just bear this idea in mind, because when we talk about feeding and all that stuff, the concepts I'm explaining apply to all of these. When I mention something, don't think that only applies to you, or the lion outside, or to the plant.

it's going to apply to all of these. And I'll try and be specific and I'll try and be clear about it. Okay.

But keep your mind open and know that we're considering all organisms, right? Because when I learned this the first time, I would always get confused and always think, wait, is this now just for me or just for the plant or just for the lion or like what's going on? So try and keep your mind open and know that when I'm talking about this, it applies to almost all of these.

Okay. Let's go into it. So feeding in different organisms. So there are three big categories of Ways of eating, okay? Autotrophs.

heterotrophs, mixotrophs. So autotrophs, okay, these are organisms that make their own food. Look at the name, self-feeding.

Auto means self, troph means like, in a way it means feeding, okay, or nutrition, okay, whatever. So because they make their own food, we call them producers as well, okay, just another word you may see pop up. Now, Autotrophs, as a definition, these are organisms that can synthesize their own food from inorganic matter. Okay, so what does that mean? What does inorganic matter mean?

What the frick does inorganic matter mean? Okay, let's go to this big brain tip. So I want to make this clear. We've got organic matter and inorganic matter on Earth.

Okay, organic matter is any kind of thing that has CH bonds. So carbon to hydrogen bonds. Okay, this doesn't really help mate. What do you mean by that? These...

Anything that has C2H bonds includes the four macromolecules. You know the four macromolecules? Like what are those things again? You know me and you, right? We're made up of billions of cells.

Now, if I go one step further and ask you, what are your cells made of? The answer is these four macromolecules. Our cell, the smallest living thing, is made up of these four things. Carbohydrates, nucleic acids, lipids, and proteins, okay?

These four things all contain carbon to hydrogen bonds. These four things are organic. Organic. So all your cells are organic. You are organic.

Okay? Now inorganic things are all the things that do not contain carbon to hydrogen bonds. Maybe they will have carbon, but they don't have carbon to hydrogen bonds. So these will be things like minerals, like for example, magnesium, iron, maybe rocks, etc.

Things like that. Anything that is not the four macromolecules. Okay? That's important.

I was never made clear on this and it makes it very confusing to understand autotrophs. Okay? So again, coming back to it.

Organisms that can synthesize their own food from inorganic things. Okay, we know all living things that have cells are organic. So in a way, autotrophs are able to use organic matter and make organic things.

Make themselves. Okay, they're able to make their own food, their own organic stuff. So how do they do that? So autotrophs can use two mechanisms.

Either photosynthesis. Okay, we know plants for example. They are autotrophs. Why?

Because plants don't have mouth. to go and eat, right? They have to make themselves grow.

They have to do photosynthesis. So plants is an example of an autotroph, okay? So they can do photosynthesis. So they can use water, which is inorganic, inorganic.

They can use sunlight, which is inorganic. They can use carbon dioxide, which is inorganic. And using all those things, right? There's gonna be a whole video on photosynthesis.

Don't worry about it. Just get the key concept. So using all these inorganic things, they produce organic things like glucose, look.

And that makes it. makes the plant grow and become bigger, okay? Very, very important. Now, to clear this up, photosynthesis. Can only plants do photosynthesis?

No! Remember I told you, don't get stuck on that. So we know there are certain bacteria that can do photosynthesis.

There are certain archaea that can do photosynthesis. There are certain eukaryotic cells that are not even plants that can do photosynthesis, like some single-celled eukaryotes. We know me and you cannot do photosynthesis, right? but a lot of these other ones can. So photosynthesis is not limited to plants.

Some other prokaryotic cells like bacteria and archaea can do it, not all of them, but some of them can, and some other eukaryotes can do it. So it's not only limited to plants, okay? So understand that.

So therefore autotrophs is not only plants, okay? It's anything that can do photosynthesis, which can include bacteria as well. Now what if they don't do photosynthesis?

Like there are other organisms, let me show you, that can do chemosynthesis. We call these chemo autotrophs because what they do is they can make their own food without using sunlight. So you know photosynthesis, they make their own food from inorganic matter using sunlight, right? Now, chemosynthesis is when they're able to produce their own energy or their own food from these inorganic molecules the same way as photosynthesis, but they don't use sunlight.

They use other mechanisms. So no sunlight. So these are called chemosynthesis.

So both of these are mechanisms by which autotrophs can make their own food. Now, I want to make one thing clear here. Chemosynthesis, like I said, like I didn't say it, but chemosynthesis, what you need to know about this is they are largely associated with archaea and bacteria. So coming back to this thing here, these two guys are largely known to do chemosynthesis. So some eukaryotes can do it.

There are some eukaryotes that can do it, but it's largely associated with bacteria and archaea, okay? So that's unique, okay? That's unique. So eukaryotes... Eukaryotes don't really do that.

Like plants cannot do that. Okay. So I hope that makes sense. So in a nutshell, autotrophs make their own food, photosynthesis or chemosynthesis, and they make it from inorganic matter.

That's it. Okay. Know that.

Heterotrophs. Other feeding and they're known as consumers, okay, because they consume other things. They can't make their own food like autotrophs They have to feed on other things heterotrophs Okay, so definition. These are organisms that obtain food from organic matter. Remember autotrophs They had to make their own food through photosynthesis or chemosynthesis by using inorganic matter to make organic matter, right?

now heterotrophs They just simply go and find the organic matter and eat it. So they can go and find a plant and eat it, they can find another animal and eat it. Because remember, all living things are made up of cells, and cells are made up of these four macromolecules which are organic. So by that logic, all like these living things are organic. So heterotrophs just go around and find living things or dead things and eat them, because all they want to do is obtain organic matter by eating it, instead of making it themselves.

Okay, cool. Now, this is where it gets interesting. Heterotrophs, there are so many categories, right?

We know eating other things can mean a lot. For example, you can be a herbivore, meaning you eat plants. You don't eat meat or anything like that, you eat plants.

Now herbivores have two subcategories, which is interesting. You can be a leaf eater only, when you only eat leaves, in which case you're a folivore, or you can be a fruit eater, in which case you're a frugivore, but both of these comprise herbivores. Some herbivores eat both, right?

So another category is carnivores. And again, they're also, all of these are heterotrophs. They eat other things to obtain their energy.

They can't make food themselves. So carnivores will eat meat. Omnivores will eat both plants and meat, right? Like me and you, we're omnivores. Now detrivores and saprotrophs, these guys are also heterotrophs because they have to consume other things to get food, but they're unique.

They're decomposers and we're going to talk about them later in this video. So for now, I just want you to know that these guys are decomposers, which means they break things down. And that's not going to make sense to you right now, but it will later. So don't worry about it. Now, these first four, herbivores, carnivores, omnivores, and detrivores, they do what we call holozoic nutrition.

Holozoic nutrition is when the organism ingests food and digests it internally inside their body. They put it in their mouth. It goes inside their body.

They ingest it. They digest it and then absorb it. And everything gets...

Assimilated. Assimilated means taken up by your cells and used by your cells so that your cells can survive. So, holozoic nutrition is internal. These guys put it in their body and their body will do all the work.

Okay? That's holozoic nutrition. Notice that the saprotroph, and again this will make sense later, the saprotroph is not holozoic.

It does not digest food internally. It does so externally, but we'll look at that later. So don't worry about that too much.

Just know about this idea of holozoic nutrition. Now, let's move on to this last one, mixotrophs. So autotrophs make their own food, heterotrophs steal and eat other organisms to get their food.

Mixotrophs can do both. That's why it's called mixotrophs. So these are organisms that can both synthesize their own food and obtain their food from organic matter. So these organisms, maybe they can be both autotrophic or heterotrophic. I'll show you an example.

There are two types. You can be an... obligate mixotroph which means you need both you need to do both for example you need to both make your own food and eat other things to survive you need both so it's an obligate you're obligated to do both then there's a facultative which are ones that can they basically can survive with one of them and then they use the other one as a supplement so there are some of them that for example they rely mostly on photosynthesis and then they sometimes can ingest other other things to as a supplement but they don't need both so they're facultative for example this guy the venus flytrap they largely use photosynthesis to survive but they can catch little insects um which is called which is um what heterotrophs do so they can eat other little things okay so this is a perfect these two are perfect examples of mixotrophs the venus flytrap and euglena euglena is a eukaryotic cell so it's a single-celled organism a eukaryote that can do both photosynthesis and take things in from the outside, like a heterotroph, okay?

So you don't necessarily need a mouth to be a heterotroph, because like I said, a lot of these bacteria and archaea, they are also heterotrophs. So you don't need a mouth. You can still take in things from the outside environment by endocytosis or whatever mechanism. So you don't need a mouth. You don't need to be a human or an animal to be a heterotroph, okay?

So it's misleading. Don't see this picture and think it's just animals, okay? It can be bacteria or archaea. That's why I keep stressing, look at this picture and consider all organisms when I talk about this. Whatever I say doesn't only apply to one organism, it's to all of them.

Okay, I hope that makes sense. The advantage of a mixotroph is that, that you guys need to know, sometimes they ask this, is that some of them can, especially if you're a facultative one, so say your environment is very low on food. These mixotrophs are lucky because they can still do photosynthesis to survive, even though food may be very low.

So that's an advantage of mixotrophs. They're more durable, so they can survive different environments more easily than heterotrophs. Because heterotrophs, there's no food, they're screwed, right? But mixotrophs are...

Nice, because if there's no food, they can temporarily do autotrophic actions like photosynthesis. Okay, now real quick, this one, we know, I just want to make this clear, because we haven't talked yet about these guys, detribors and saprotrophs, so I want to talk about that. We know that inorganic things like sunlight, water, and soil, right, and all that sort of stuff, and carbon dioxide, plants can use these inorganic things to synthesize themselves, right, through photosynthesis, they grow themselves, they are autotrophs, right?

So by using these inorganic things they grow themselves and they are organic because they're made up of cells right all these four macromolecules Now other organisms like heterotrophs can then consume these plants little small organisms And then bigger organisms can eat those animals and then bigger animals can eat those animals. So eventually that's heterotrophic action, right? So then we have a big animal eating these small animals. Now, is that where it ends? No, it's actually a cycle Believe it or not.

So when these animals these heterotrophs die They don't just sit there and die, right? They eventually go away, right? If you've noticed, when something dies, it gets taken away essentially.

After a while, it'd be completely decomposed and gone. Why does it decompose? Because of these two fellas, detrivores and saprotrophs.

These two are heterotrophs, remember? We put them here. But they are special, they're decomposers.

So their job is to recycle dead organic things, like dead organisms, and recycle them into inorganic things. plants can use those inorganic things again and the cycle can continue. Now their difference is in their action. So they have different ways of decomposing dead things.

Let me show you. Let's start off with the worm here, the detritivore. So these guys are decomposers. So decomposers are any organism that breaks things down.

So when this thing dies, it's no longer useful. So we want to break it down. all these macromolecules that it's made up, we want to break them down smaller and smaller and smaller and recycle them into inorganic things, right?

So decomposers are going to do exactly that. They're going to break down this dead organic matter, something that died, by directly consuming it, meaning putting it into its body, ingesting it, okay? Internally, they ingest it and digest internally, which we call holozoic nutrition, okay? Internal ingestion and digestion is holozoic nutrition, right? Remember that.

So examples can be earthworms, wood lice, and other insects, right? So they're going to be useful at kind of eating this thing and breaking it down after it died. Now saprotrophs are very different. They're also decomposers, but they act differently. These guys break down the same way.

Dead organic matter, but their mechanism is different. What they do is they don't have a mouth to ingest it and break it down by holozoic nutrition. No, they're going to release little enzymes.

Examples of saprotrophs are fungi and little bacteria. Okay, little bacteria. These guys release enzymes onto the dead thing.

Okay, and those enzymes, remember enzymes are like little tools, little molecules that make certain reactions happen. Now these enzymes, the specific reaction that they're meant to make happen is the breakdown, the decomposition of this dead thing. So these enzymes are going to be released onto this dead organism and it's going to start breaking it down. Now when it's starting to be broken down, those nutrients can be absorbed by the saprotrophs, okay?

So you can see it was different. It didn't do internal digestion like the detrovore. It does external digestion.

It's different. Everything is happening outside of the bacteria, outside of the fungus, okay? So that's why they are not considered holozoic nutrition, okay?

Very important. But in that way, look what they managed to do. Something died They decompose it and return it as inorganic material so we can continue this life cycle.

Okay, that's why if something dies, if you come back a week later, it'll be smaller. If you come back a week later after that, it may be even gone. Maybe only bones remaining, right? So this, that idea, it's not just magic. It's these guys.

It's decomposers acting. Okay, so I hope that makes sense. So that's the big idea here for feeding in different organisms.

I hope that makes sense. Okay. So we've covered now a lot. We've done all this. We've done now this autotrophs, heterotrophs, mixotrophs.

Now we need to talk about dentition. Okay. Believe it or not, you guys need to know about teeth. So let's get into it.

We know to eat, we need teeth. Okay. And it's going to be interesting because we need to compare different organisms teeth because different organisms eat different things.

So they need different features. Their teeth need to be a little bit different shape, different structure to be able to eat what they need to eat properly. Okay. So here we go.

We got some teeth. Let's take a human. This guy's from the Guinness World Book of Records, okay?

Look at his teeth. I'm gonna be quick with this. So you can think of your mouth as having four quadrants. One quadrant here, one quadrant here, one quadrant here, one quadrant here. Okay?

Now each quadrant is the same as the other ones. Okay? So we're gonna take it one quadrant here and then you'll understand it for the other ones, right? So you see here, let's take this side here.

These two teeth here, okay? These are incisors. Look at them.

They're like little, they're very thin. They're like little blades, like little blades. Okay? These we call incisors. They're your front teeth.

You have four of them in the front, but two belongs to this quadrant and two belongs to this quadrant. So in reality, you have four at the bottom for your bottom teeth and four at the top. But for each quadrant, you only have two.

OK, then these teeth are very sharp. Like I said, like a blade. They're used for cutting off bite sized pieces of food.

So if I give you a sandwich, the first teeth you're going to use is the incisors to break it apart into smaller pieces. Right. That's the purpose of our incisors.

Adjacent to the incisors, so these two are incisors, adjacent to it here we have a sharper tooth called a canine. Sometimes they also call this a cuspid. Now these teeth are sharper, you can look at yourself in the mirror, they're pointy. These are used for ripping or tearing tougher materials such as meat, right?

And we are omnivores, so that makes sense why we have these teeth, so we can eat meat as well. Based off evolution we have these teeth, so it's sharper and pointier, different from the canine which is thin like a blade. Then we have this here.

I see here adjacent so per quadrant we have two incisors one canine two pre-molars so we call these pre-molars because they are before the molar so these two are pre-molars and then after the pre-molars we have the real molars okay now pre-molars as you can see they're kind of flat and and wide okay and these teeth are used for and you can see the surface is very bumpy okay a very bumpy it's got like some peaks and some dips These are used for crushing or slicing food, okay? Because you know when you bite off a piece of food, you don't want to swallow it like that. You want to break it and crush it, make it smaller, right? So our premolars will help us crush and slice the food into smaller pieces, even more smaller pieces. Then our last three teeth are three molars.

These teeth are used for grinding and reducing it to a paste for swallowing, okay? For swallowing. So basically grinding it into a liquid so you can swallow it very easily. Another name, remember how I said for canine it's also called a cuspid?

The premolar can be called a bicuspid and then molars can also be called tricuspid because they have two bumps So bicuspid and this one has one cuspid, two bumps, bicuspid and these have three bumps So we call them tricuspid sometimes so don't worry about that too much So you can see there is a difference between the molar and the premolar Their top surface has three bumps if you're a molar and two bumps if you're a premolar, okay But they have a very very similar function of grinding and breaking down tooth into smaller pieces Now We need to compare now how teeth are different between herbivores carnivores and omnivores. We're going to go quickly over this I think it's pretty straightforward. So herbivores have very large. I'm just going to use this image I'm going to show you a picture on the next slide, which will make it easier So i'm going to click over this because we're going to explain more detail on the next slide So herbivores have very large incisors Okay, because they have to cut up leaves and make them into smaller pieces cut up fruits into smaller pieces when they bite them, right? Because you can't put a whole fruit and swallow a whole fruit like that.

You need to break it into smaller bite-sized pieces. So they have large incisors. And they're very wide premolars.

Okay? I kind of like this. Very wide.

Because they need to grind the fruits and the leaves into small pieces and they can swallow them. Okay? See, like I said, the molars of herbivores are very rounded and have very rounded peaks and valleys. So they can grind food very easily.

Now, what's different about carnivores? Carnivores, they're incisors. Okay?

And they're canines, so these teeth are very very sharp. So ours, our canine is a little bit sharp, and our incisors are not sharp. They're more thin, like a blade.

Now for carnivores, their incisors are very sharp and pointed because they need to kill things and they need to rip meat apart, right? So it's good for killing and breaking tough meat. And their premolars and molars are much different from ours. I'll show you a picture on the next slide. But their premolars and molars are not round and, I mean, not flat and wide like this.

It's serrated. Serrated means like a saw. and it's very narrow so it's much different from ours you'll see it later okay on the next slide now omnivores like us will have a mixture of of the features that herbivores have as teeth and what carnivores have as teeth so we're gonna have a nice mix so that we can eat both meat and plants so our canines will not be as sharp as carnivores um it will be in the in but it won't be as blunt as herbivores so it's going to be everything will be basically a mix we're going to look at it on the next slide in more detail so don't worry too much now Other clues.

So scientists, when they find a dead body, they like to examine it. Now, one of the things they like to do is look at the teeth, because from the teeth, if they haven't seen this organism before, they can judge, based off the teeth, what kind of diet this organism had. Because I told you, all of these different features can correspond to a certain diet. So scientists can look at the teeth to judge what the diet was, but they can also look at the teeth under a microscope to look for microware. Microware is little cuts and abrasions, little scratches.

on the tooth that we cannot see well with our eye but under a microscope we can and those patterns on the teeth will correspond to the certain food that this organism eats because softer food will have a different pattern or different abrasion different marks compared to harder foods so and scientists can also use this idea to help them out okay now I want you to make this clear. Teeth are not always only to indicate diet. Sometimes organisms'teeth will be misleading because look, this gorilla, it only actually, it's a herbivore, but look at its canine. It's so long and sharp. So you need to know that sometimes canines, sometimes teeth are not only going to be accurate to what the diet is of an organism, but it may also have other features like, for example, intimidation.

These guys are not for eating meat. They're rather for intimidation, right? Because if we look at a tiger here. Look, it's also there for intimidation, but we know a tiger is a carnivore.

So we know these canines are actually going to be used for eating meat. Okay, look how teeny tiny their little essential incisors are, right? Because they're not leaf eaters and they're very sharp and pointed, right? Very sharp and pointed and small.

We know herbivores have very large incisors. You can see here, their incisors are much bigger than the tigers. Okay, so that's so interesting. You can look at different pictures of animals and look at their teeth and compare it to this and can kind of guess what their diet is. It's really, really cool.

Okay, let's go on to the next. So now I want to quiz your knowledge here. Okay, here. So look at these. Tell me what you think it is.

Let's start here with our little thing here. This is going to be a carnivore. Why? Long, sharp.

Let's put it here. Sharp and pointed incisors and canines. Very sharp. Great. Why?

For eating meat. I mentioned on the previous slide, right? But let's, I said I want to show you a little bit more about the premolars, how they're different in carnivores.

Look, I said that they're very serrated and narrow. Look, if you look at it from the side view, you can see they're so sharp, like a saw. Okay, very sharp for breaking apart meat and killing things.

If you look from the top, it's very narrow. See, that's what I meant by serrated and narrow. Very, very different from humans and herbivores that have very wide and flat molars and premolars. That's very important.

Okay. Cool, so I hope that makes sense. The same goes for the molars at the back.

Okay, let's look at this. Now how about this? This is a herbivore. How do we know?

It's got nice and large incisors for breaking that fruit into smaller pieces and it's nice and large compared to the carnivores. The image is a bit misleading but herbivores have very large... Sorry. very large incisors and wide premolars and then their molars will be wide and flat kind of like humans and then again humans will be right in the middle so our canines will not be as blunt and as small as the herbivores but it won't be as big as the carnivores and our molars and premolars will not be as flat and as wide um as the herbivores but it won't be as sharp and serrated as the carnivores okay so it's really a mix um sorry let me fix this That's right omnivore. Okay, so my artist wanted to say that this doesn't look good because I made this design here of the guess the diet Like like I was like this looks pretty sick, but she was like nope if that was her choice She would not have made that so She was asking you guys to say basically do you agree with me or do you agree with her?

Now so that's it for diet. Okay, so we need to do one last thing then we're done I'm going to rush over this you guys need to for some reason I don't know why I need to know about the great apes and their diet. So we're going to go over it real quick Now the great apes is a bunch of organisms that belong to the family Hamanidae. Remember when we classify organisms we classify them into domain, kingdom, all the way down to species right from general to specific.

Now all the great apes belong to the family Hamanidae so there are different genus and different species of all these great apes and I have five of them all right here okay. So when we look at them we can see that Let's look at them. Maybe you know some of these names. Try and guess some of these names. What do you think this one is?

This one is an orangutan. This one is a gorilla. Chimpanzee. Bonobo. Homo sapiens human.

Okay, so you can see here I tried to put a scientific name to make it make sense. Remember all of these fall under the category of family But they're gonna be different genuses and species. So you can see here the orangutan falls under the genus Pongo. There are various species of orangutans. So that's why I put XXX here because there are multiple species, but Basically, all orangutans are under the category genus.

Now, gorilla, same thing. They fall under the category gorilla, but there are multiple gorilla species. Now, chimpanzee and bonobo, they both fall under the category genus, the same genus, the same genus category called pan, but they are different species. So they're both the same genus, but they're different species. Now, human has a different genus called homo, and there's only one species in the homo genus called homo sapiens.

That's us. All the other ones died. right extinct now we need to know a little bit about their diets i'm going to quickly show this i don't want to waste time with this orangutans all of these are omnivores so they can eat plants animals insects all that sort of stuff but orangutans they are omnivores but they're preferential frugivores so if it was up to them they would only eat fruits gorillas if it was up to them they would only eat leaves okay chimpanzees they eat both so they can eat little insects They can eat little animals, they can eat little plants, fruits, okay?

They're kind of both so we so they're both of these both bonobos and chimpanzees Um are omnivores they really kind of eat anything. Okay Followable remember for gorilla and what about humans? We're omnivores, right? We are able to eat meat and plants and everything, right?

So here I want to show this quick. I'm not gonna use time on this So I want to show you the relationship between all of these great apes from where the great apes are just all the organisms under the family I'm on a day. Okay, and they include these five and you can see Long ago they had an ancestor.

So before all these existed long time ago our ancestor and over time we can see longest ago a derangatang species evolved and after that when time passed gorilla evolved then after that human evolved and then after that the chimpanzee and bonobos separately evolved okay so this is kind of i don't don't worry about this it's just there to show you um it's not very important just it's cool to see the relationship because you can see that humans are pretty closely related to chimpanzees and bonobos in time we evolved pretty recently into separate pathways now lastly Monkeys! You don't need to know this so you can skip over this, but I was very curious. What's the difference between monkeys and apes?

Basically, real quick, I'm not gonna write anything down, so it's not important for you guys, but monkeys have tails. Apes do not have tails. Monkeys are...

have small... they're smaller. They're very small, compared to this the size of apes.

Also, monkeys, their arms and legs are proportionally very long compared to their body, compared to apes. Also, monkeys are more crawling. Apes can be on... can be more upright. their stature, their posture is a bit different.

Okay? So those are key differences. Just so you know, it's pretty interesting to see the difference between what apes are and monkeys are.

So monkeys belong to a completely different classification. They do not fall under the same family, okay, as all these great apes. And I'm telling you, these come up in multiple choice questions. I saw a question where they ask, is a lemur part of the great apes?

And the answer is no, right? So you should know that these are all part of the great apes, okay? Please, it might come up and...

I don't want you guys losing points over that, okay? So, okay, so that's it now. We're done now.

All the way up to here, we're gonna come now next into aerobes and anaerobes. So we talked a lot about food now, but there's one more thing that we consume every single day, and that's oxygen. Now, believe it or not, there are some organisms that cannot stand oxygen. They despise it.

They will die in the presence of oxygen. Now, so that brings us to the topic here of aerobes and anaerobes. Got to talk about this concept.

So look at this diagram here. On the right side, you can see we have a little diagram with... This side here has very low oxygen concentrations. And as we go to this side, the oxygen concentration, the oxygen level increases. So what do we call these organisms that really need oxygen?

They cannot survive without oxygen. We call them obligate aerobes, okay? So what does that mean?

These organisms need oxygen. Why? Because you know to break down food like glucose, into ATP, we need to do cell respiration. Now, you know, there are two types of cell respiration, aerobic and anaerobic cell respiration.

Aerobic is the one that needs oxygen and anaerobic is the one that doesn't need oxygen. So these guys to survive, they need to carry out aerobic respiration, which means they need oxygen. Otherwise they cannot break down their food to make ATP, to make energy. So that's very important to understand. On the contrary, we have these guys here.

They hate oxygen. They're called obligate. anaerobes, meaning they don't like air, anaerobes. So it's not aerobes, it's anaerobes. They hate oxygen.

So how do they survive? Because don't you need oxygen to do aerobic respiration? You're right.

So they don't actually like aerobic respiration. They're going to do something else. They're going to do anaerobic respiration. They're going to break down their food without requiring oxygen. Okay, so that's very important.

That's why they hate oxygen because they like anaerobic respiration. Now right here, this last one right in the middle, we've got facultative anaerobes. So they're kind of in the middle. Okay, they can do both. They're okay with aerobic respiration.

They're also okay with anaerobic respiration. The presence of oxygen will not kill them or the absence of oxygen will not kill them. They're not very picky.

They're fine with either. Now, sometime before we move on out of this anaerobic and aerobic thing, we got to talk about this. Sometimes on the test, I like to give you a little test tube like this as one of the questions and ask you, is this organism obligate aerob, anaerob or is it facultative anaerob? So this red thing here is a little organism and you got to be able to answer that.

So what do you think? When you look here, we know this area of the test tube is full of air, oxygen, and this is full of fluid like water or something else. You can notice obligate aerobes in this scenario would go as close to the surface of the water as possible because they are there, they are as close to the air as possible and they need air to survive.

So this is how obligate aerobes would like arrange themselves in this sort of setup. So if you see this somewhere, don't be confused. Now the opposite ones, obligate anaerobes will do the opposite.

They will go to a... deep as possible into the water as far away from this oxygen level as possible okay because they they need anaerobic respiration right they hate air now the facultative anaerobes guess what right there in the middle they can do both they're not picky okay so where do we find these obligate anaerobes like where do these kind of organisms exist that's very important to understand they exist in areas with no oxygen right so where very very deep in the ocean very very deep under the floor in the soil in our bodies even, even in our intestines, because in our intestines there's very low oxygen levels, okay? So they can exist anywhere where the oxygen level is very low.

So that's it for anaerobes and aerobes, okay? It's very important to understand that, remember, these can be bacteria, anaerobes, any of the things I mentioned before, eukaryotes, archaea, bacteria, it's not limited to any specific one, okay? So just understand this big concept of aerobes and anaerobes.

Awesome. So now we're done with that and we're going to go over to this next aspect here. Adaptations.

This is going to be really really fun We have a nice slides because we know this is very boring to read about in the books We made nice slides to make this easily rememberable for you guys and it's very important So let's start off with adaptations of predators. We know predators the bad guys right in the movies They want to kill they need to go and catch the catch the prey, right? They're the alphas as we like to call them, right? So we know that these predators They're gonna have three kinds of adaptations to make them very good at being predators, okay?

So we can split them into three categories. Physical, behavioral, and chemical, okay? You need to engrave this into your mind.

Because I'm gonna give you a lot of examples. But I don't want you to be too fussed on remembering all these examples. Because there are billions of examples on earth in reality, right?

I'm only gonna give you a few. But what you really need to understand... is that these three categories are important because all adaptations will fit under one of these three categories no matter what organism you take.

So this is important, don't be too fussed on the examples. I would recommend you remember a few examples for your test in case they ask you, name some physical adaptations that a predator may have, okay? It is important, but don't get too fussed on it because you can even go and find your own examples, okay? You can't lose marks for that, but you will lose marks if you don't remember these three categories.

So let's start with physical. Okay, I like this one because I picked a bird like a hawk or an eagle and you can already remember four physical adaptations Just by remembering this bird. Look, we know sight is a very important physical adaptations.

Being able to see your prey from far away Maybe see it in the dark if you're an owl You should be able to kill look the claws the beak teeth if you're if you're a lion or something So very important movement, maybe this bird it can fly. That's awesome. But cheetahs run, whales swim right so all of these are physical adaptations things their bodies can physically do different right that helps them be a good predator smell right vultures they can smell their dead things from far away and go there because they're pretty lazy right they can't kill their own organisms they're gonna wait until something died and find it i like this one a lot you know sharks they have this unique ability this physical adaptation where they can pick up little electrical signals that fish produce when they swim damn right how do they do that they have this little special thing let me show you Oh sorry They have this special thing on their face, many little holes, you can actually google it, it's like many many thousands And they call these little organs, or whatever, ampulla of Lorenzini And these guys can pick up these electrical signals, and this helps them know where the fish are Because the fish, when they swim, they'll produce these So if the fish is close, the shark will pick up all these little signals and know there's a fish that's close So that's very unique to sharks, right? Here's another one, look at this It's called echolocation, you know some dolphins, they can make sound waves And these sound waves, when they send them out, they bounce off of certain things back towards the dolphin. So the dolphin can both send these sound waves and pick them up.

Okay, so they can tell exactly how far this organism was that the sound bounced off, whether it was far or close. And that can kind of guide them to know which way to swim. So that's very, very useful. Echo location.

Last one here, brain, right? Me and you, even other organisms, brain is so important to make you make decisions when you're a predator. Is it safe now to attack? Is this the best time to attack?

Should I rest now and save my energy? All of these are things your brain is doing in the background, right? So a brain is a very important physical adaptation for predators. Let's move on.

So that's physical. Let's move on to behavioral. So this is pretty, pretty cool. One category of ways in which a predator can behave as an adaptation is ambushing, right? Some predators just wait.

They're lazy. So like spiders, they make a web and they just wait for the organism to come towards them. and then they eat the organism when it's there.

Another example is these angler fish, right? From Nemo, you know, they have this little dangling light deep in the ocean and the fish like the light, so they go towards it. So this thing is just waiting for the fish to come towards it and then ambush it, kill it.

So ambush, one very big important behavioral characteristic of a predator. Next, pack hunting. That's pretty straightforward, so I'm not going to explain that. We know lions do that, wolves like to do that.

Teamwork, very important. So next, pursuit predators. So pursuit means to chase.

Now, we know some organisms like speed, like cheetahs. They're very fast. They can physically outrun their prey and catch them and eat them, right? Over short distances. Because these organisms like cheetahs are not very fit, right?

So they can go fast for a very short distance. Now, other organisms, maybe they're not as fast, but they are very endurant. They're very fit, like humans.

These organisms will just follow their prey forever until the prey gets so tired that it just dies from fatigue or falls over. And then the organism can eat it. So these are both pursuit predators chasing, they chase their prey either through speed or through persistence, right?

Different organisms will be in a different category. So that's important. Now that's it for behavioral. Let's go on to chemical So chemical is also really interesting So these were physical things that the organisms had these are behavioral and now these little molecules that certain Predators can make to help them kill their prey certain adaptations. For example venom We know the black mamba.

It's one of the most venomous snakes, right? It can make a little poison that paralyzes and kills their prey. So it just bites them, waits for a while until the thing drops dead and they eat them, right?

That's a chemical adaptation. Next, pheromones. Wow, I find this one really, really fascinating. You know, pheromones, these are little organic molecules, just molecules, not organic, anything that's for macromolecules. These are little organic molecules that are made by certain organisms to attract a mate, okay?

It's a kind of, it smells very nice and the mate wants to come towards them. Now, these little guys, these spiders, they're pretty cool. They can make these pheromones that mimic the pheromones of other organisms. So when this guy makes these pheromones, one moth will be like, oh I like that and will go towards it because it thinks it's going to go towards another moth. But actually it's going towards a spider that made a pheromone that mimics the moth sex pheromone.

So that's a pretty nasty trick right? So that's another chemical adaptation. See all of these random examples. So I really just want you to know these three categories.

Remember some of these examples. It will really help you for your test. But don't get stuck on these. You can find your own examples. That's the important part, okay?

So now that's it. So we did now the... Predators, let's go over to prey. So preys, these are the guys that need to run away, need to escape from the predators, right? So they're gonna have different adaptations compared to what the predators had, right?

So let's look at them, but Important, it's the same categories physical, behavioral, chemical. Again engrave this into your mind for the love of goodness, okay? So let's go into it, physical. So these guys are different, they gotta hide, so camouflage is very important So they cannot be spotted by the predator. For example, color they can blend in with the background.

Texture, they can change the texture. So there's certain octopuses that can change the texture of their body to match the texture of the thing they're on to help them camouflage. Another one is aposemitism. So there's this like...

Aposemitism is the concept by which an organism does something or looks a certain way to be less appealing to a predator. So for example, this frog, okay? Maybe it's super super colorful. And because it's very colorful, the predator, when it spots this frog, it's not going to want to eat it. Because it's going to think, oh, it's very poisonous, I don't want to eat that.

So that's aposemitism. When you make yourself, when you look a certain way that kind of dissuades or chases away the predator just by the way you look. Okay, so that's very important. That's aposemitism.

There are even some crazy examples. There are even some snakes that are not dangerous at all. But then... They do aposemitism in the sense that they look exactly like a very dangerous snake.

So when an organism sees that snake, even though it's not dangerous, because it looks like a very dangerous snake, it will not be attacked. Okay, so that's very that's a very cool physical adaptation of certain preys. Next is noise, right?

Some organisms like monkeys make the hell out of noise, and if the whole group makes noise, you're not gonna want to go there, because it sounds like there's a lot of organisms there, and the predator will not want to go there to mess with them. Next... This is probably very straightforward.

We know turtles and stuff. They have shells to physically protect them when they're being attacked. Same as grasshoppers.

They're pretty hard. They're exoskeleton. Snails, clams, even porcupines or hedgehogs or whatever. They have very sharp spines. And this makes them very less tempting to bite or eat because it's going to be sore for the predator.

So these are all the physical adaptations of our preys. The guy is running away. Let's go on to behavioral.

So behavioral is also really cool for prey. And you can kind of guess a lot of these. You know...

prey they generally like to what if you look the the movies like national geographic they're always what run away they're avoiding that's this is more something i would do i feel like i'm an avoider um if something comes to me i'm not gonna try and be brave and fight it i'm avoiding i'm hiding it's in my dna goddamn so these guys avoid that one of the things like to avoid but there are other ones other preys that don't actually avoid this is actually smarter they do group formation so they feel there is safety in numbers for example elephants if you've ever noticed elephants when the lions are around they will form the circle where the biggest elephants will locate themselves on the outside of the circle facing outwards towards the lions and then on the inside you'll have the babies and the weak older elephants being protected and so the lions are less likely to now attack because the vulnerable ones are hidden in the group okay and the lions are more likely to get injured if they decide to pursue an attack okay so that's important either avoiding or group formation is a common uh at a behavioral adaptation for prey Okay, let's go to chemical, last one. So chemical, you know, we know chemicals, little molecules that can be made by these preys to protect themselves through two ways. Either bad taste, maybe they make a really freaking foul smelling molecule that the predator doesn't like and wants to stay away just because it tastes so bad, man.

And the poison, it can maybe be poison. So if the predator does in fact eat this organism, it may die because the chemical that this predator prey has will be poisonous, right? and that will basically prevent the future attacking of this certain organism. Okay cool, so again physical, behavioral, chemical.

Awesome. So now what we did is, I apologize guys that this video is too long, but I just want to really go slowly and carefully over all these things. I don't feel, I feel like there's no use in rushing anything. There's no point in that, so I apologize if it's long, but I hope it's useful and I hope it's going to help you guys out. So let's uh, we finished this one here, Adaptations of Predators and Prey.

Now let's go on to heterotrophs and plants, right? We know heterotrophs are organisms that eat other organisms, right? I think what I really meant here was herbivores, so I'm gonna change that. Because heterotrophs can be predators.

So herbivores are more things that eat plants. So we're gonna look at herbivores adaptations and plants adaptations. So let's first look at our plant adaptations.

We're going to split the plant adaptations into two kind of categories, okay? Plants need to be well adapted for harvesting light to do photosynthesis, right? Because plants, as I said, are autotrophs. So they need to harvest light to make energy through photosynthesis.

So if they do not have access to light, they will struggle to survive. So plants have certain adaptations to gather or harvest as much light as possible to survive. So if we look at this typical environment, We can see a lot of different plants here already and they all have different adaptations to harvest as much light as possible to survive.

When you look at a forest you can see various layers. Look. We got the top layer of this forest will be considered the canopy, the highest area of the forest.

Below that, we have the understory. Below that, we have the shrub layer. And below that, we have the forest floor.

So all these layers. And you can imagine when light comes into this forest, most of the light will be taken up by this canopy, the upper layer. And the light will be used up and less will reach deeper levels.

So the deeper we go, the more shadowy it will become. The less light will penetrate down to these levels. So I'm gonna give you some examples of organisms or plants in these different levels and how they are adapted to harvesting as much light as possible To do photosynthesis.

So trees We know trees are really really really tall and they're able to stand so tall and reach these canopy the upper layer of the forest Because they have a sturdy wooden trunk a very strong trunk So the disadvantage of this is it takes a lot of nutrients to make a trunk like this be able to be so high right, but because of that they can reach the most of the light and grow okay so they're above their competitors that's their advantage next we have these guys notice them they don't grow from the floor they actually grow from it's both of these they grow from the the branches of trees so they're kind of cheating they're able to be here in the canopy and understory the high layers of the forest not because they grew to be up there they're growing on they're using the tree as a scaffold isn't that crazy so that's a pretty cool adaptation so they're using the tree to their advantage Okay, next we have this guys, you know these guys from Tarzan, he swings on these. So these guys are pretty cool They, unlike these epiphytes, they actually grow from the soil Okay, they root themselves in the soil and they grow up but unlike a tree they cannot make such a strong woody trunk They can make a trunk, but it's not as strong So the only way they can get very high to get more light is by using the tree as a scaffold So what they do is they're unique because they grow away from light not towards light away from light So when they grow away from light that means they're gonna grow towards the trunk where there's the least light right? Because the leaves are blocking it so their trunk area is gonna have very little light so these guys these lianas are gonna grow towards the trunk and kind of wrap around and go higher and higher and higher and Therefore be able to reach these higher layers like the understory and the canopy where there is more light to harvest So that's really really really cool But the problem with them is because they come from the soil, you know the soil has certain nutrients in, right?

That the plant will absorb to grow. You can imagine now this means that this tree and this liana They're sharing the same soil, which means they're competing for nutrients So this liana keeps on growing becoming bigger and bigger and bigger wrapping itself around this tree Eventually, it's going to be so competitive that the tree is going to die because this liana is stealing all the nutrients Okay, so that's very very tricky. So a liana can actually kill a big tree like that just so so easily.

Okay, cool Next we're going to go to one of these lower layers like the shrub layer forest floor this layer where the plants are much smaller They're not able to get to these higher layers Now what is their adaptations because unlike these these other ones we talked about They are not able to get so high to get a lot of light to do photosynthesis So instead they are adapted to be able to survive in a very shadowy environment very dark environment. So What's interesting is when light passes down here most of most of the wavelengths of light is taken up here already So only a few manage to penetrate deep to the forest floor or the shrub layer Now these plants are adapted in the sense that they're able to use this remaining light to their advantage So they're very good at taking up this specific wavelength that manages to reach these lower levels Okay, and that allows them to survive despite very inadequate sunlight now these organisms We kind of call them herbaceous plants or herbs or herbs as some people like to call them These guys are different from these other ones because they are non-woody. They do not have a stem Okay, like that like a tree or like these lianas or things like that They are non-woody so they don't have a stem or a trunk or things like that So that's what that's that's why we call them herbaceous plants. So these include like banana trees strawberry bushes things like that.

You can google more examples if you want. So these are called herbaceous and non-woody, different from all these other ones. Okay cool, so I hope that makes sense.

So these are the adaptations of how different kind of plants, depending on where they're situated, what level they're situated in in a forest, how they can get as much light as possible to survive. Okay so that's awesome. Now we're going to go over to the different adaptations. So we're going to talk now about the adaptations of plants.

The adaptations of plants in the sense that that is not related to photosynthesis. More adaptations in the sense preventing them from being eaten by a herbivore, right? Herbivores like to eat plants.

So these are going to be adaptations that prevent plants from being eaten by a herbivore. So for example, let's look at a tree trunk. Have you ever tried eating a tree trunk?

I'm sure you haven't, right? It's freaking hard. The bark is really thick.

It's just not nice, right? So this prevents a lot of organisms from penetrating and getting into the tree to get all the nutrients. Even these guys, cactus.

They have a lot of thorns. Have you tried eating a cactus? I'm sure you haven't. It's very thorny and spiky It's gonna hurt the hell out of you, right? So that's very cool.

Also these I don't know if you guys have had these I don't know if you ever had this like allergic reaction. There are these little plants Um that cause urticaria. It's like an allergic reaction So how they work is these guys have little chemical irritants inside of them.

You notice the color by the way You see how I made these red Uh because they're physical adaptations and these yellow because they're chemical adaptations. So I try to correspond them to the to these so chemical yellowy red um physical there's no blue ones because plants don't have behavior they don't have a brain or anything like that so they don't they don't have any behavioral adaptations because i didn't want to make more cards for you guys i felt like that would have been made the video a bit more boring to do this again for the plants so i did this for the predators and prey the card idea and i tried to make a different kind of concept here a different diagram for the plants and the herbivores so it's not as boring okay So again, anyway, so these guys have little chemical irritants in the little hairs. If you look at them, they have many little hairs. Now, there are little chemical irritants in these silica little hairs. Now, they are not exposed to the outside yet.

But when an animal walks past them and breaks those hairs, these little chemical irritants will come out and get onto the organism that walked past this thing or tried to eat this thing. And these chemicals create an unpleasant stinging or burning sensation. You must have felt this before if you've touched this plant.

Okay, and this is very useful because then when this organism encounters, when the herbivore encounters this plant again, it will be hesitant to eat it because it knows it's going to get an uncomfortable feeling from it, okay? So that's very very cool physical adaptation of this kind of plant. Now what about this one here?

So these guys are called foxgloves or digitalis, okay? These guys are unique because they physically make certain toxins. Now when a plant makes a toxin, we call it a phytotoxin.

So phytotoxin is just a name given to a toxin that a plant makes. And if an organism eats these guys, they can get very, very sick. They can get heart problems. They can get hallucinations.

They can even die. Okay, so these are just little toxins that are made. Another kind of adaptation. Now the last one here before we move on to herbivores is the castor bean.

So the castor bean is very, very nutritious. So it's very, very tempting for organisms. Because when they eat it, they get a lot of nutritions in it.

But inside this castor bean, it has a very toxic toxin, highly toxic toxin called ricin, that can basically kill you. Okay, now, so, but the thing is, humans use this castor bean to make castor oil. So why do we survive? Because when we cook this, when we prepare this bean, when we make the oil, when we extract the oil, we put it through a lot of procedures that removes this toxin. So we can, in fact, consume this oil and not die because we remove the toxins.

But other organisms like herbivores cannot do that, right? So that's all for the adaptations of plants, right? So of course plants can shoot bombs and shoot things like plants versus zombies, but they have these other cool features But I think it's still pretty awesome. Now, let's go to adaptations of herbivores.

So these are more straightforward, right? What do herbivores have that makes them good at eating plants? First of all giraffe We all know they have really long necks to reach the leaves at the top of the forest Okay, which the other organisms can't reach and they also have really really tough tongues because a lot of the trees have a lot of thorns in them, which would not be...

which try and protect the tree, right? Like I mentioned, we saw here thorns are... can be very...

can protect certain plants. Now, giraffes have very tough tongues which helps protect them against these thorns, so they can still eat a lot of leaves without getting too much damage. Now these guys here, grasshoppers actually have really...

a mandible is basically your jawbone, so they have very sharp pinching jawbone, so when... so they're very easily able to cut grass and leaves. Because you know leaves are actually very strong because leaves are made up of plant cells which have a very nice cell wall have a lot of other materials that make it a bit tough for small organisms to eat but grasshoppers have very sharp pinching mandibles that helps them cut apart this thing so it can basically eat it. Essentially, it helps them physically take this thing into its body by breaking it apart.

Now you know, if you look at a leaf You know, if you look at a leaf, it's got many layers, right? And we know the top layer has a lot of cells that have a lot of chloroplasts that can help it do photosynthesis. It's got a lot of xylem and phloem. You learn about this in other chapters, which have a lot of nutrients in them.

So there are organisms like this one here, okay? These organisms, these aphids, they're called aphids, they have these long stylettes. Stylettes is like a sharp pipe that can suck things out. So because they don't have a nice jawbone, like these grasshoppers, to bite this leaf open and get the nutrients out, they can't do that. Okay, they don't have that jawbone those pinching mandibles.

So they actually have a stylet So they pierce this through the plant into the nutritious area of the leaf and suck it out So that's really really cool adaptations. They drink the sap like that Now lastly here we get to cows and organisms like that. So cows we know we already talked about teeth so I'm not gonna talk much about that, but they have specialized teeth to be able to grind leaves and plant matter and Consume it right Now ruminants, so we know cows are an ex-like ruminants is a big category of organisms that actually swallow their food before chewing it.

Later on, they will regurgitate, meaning bring back up this food and chew it again. We call that cud. Cud is the little regurgitation, regurgitated food. Okay, so they'll regurgitate it, eat the cud again, swallow it again, regurgitate it.

So we call these organisms ruminants. Okay, so this is another kind of adaptation that ruminants have. It helps them digest food better. That take a long time to digest. Now, you know, cows and certain organisms actually have a lot of microbes like bacteria and archaea in their body, okay?

So what's the advantage of this? The advantage of this is that these bacteria and things can make a lot of enzymes and these enzymes can help digest certain certain plant material because normally cows don't have enzymes to digest cellulose. You know cellulose is a component of plants Normally they can't digest it but these enzymes made by these bacteria and archaea can so that's useful It's basically these microbes are working for the cow. Okay, and also these microbes they can also make certain toxins I mean certain molecules that help detoxify certain toxins because you know I told you a lot of plants have a lot of toxins So when cows and stuff have to eat them, they may die. But certain organisms have a lot of anti-toxins, like things that help neutralize these toxins so that they don't die immediately, so that they can eat a little bit and still survive.

Okay, so that's very, very important. So a lot of organisms do something called cautious sampling, where they will eat some plants as they go along, and just to make sure that they're not dangerous. So if they eat a little bit, then they'll maybe feel bad and know, oh, I shouldn't eat that again.

So they do something called cautious sampling, which... helps them test out different plants as they go along to figure out which ones are healthy to eat. So that's it for the adaptations of herbivores. Again, I hope that was useful.

Let's do some questions and then we're done with this video. I know it was a lot. So which of the following features are likely to be found in carnivores?

Sharp-pointed canines, yes, right? They are very sharp-pointed canines to break apart that meat. Thin serrated premolars, yes, they do. Wide and flat molars?

No, they don't. They don't have these. These are herbivores or maybe omnivores. So one and two are correct. So the answer will be B.

And again, check out teachme.org for a lot of awesome notes and lots of IB style questions, okay? So which of the following primates does not belong to the great apes? I told you questions come up on this.

We know orangutan is part of the great apes, gorilla is, human is, lemur is not. That's a monkey. It's got a tail, okay? So C is not the answer. I mean C is the answer.

Which of the following terms describes the place where an organism lives and the role it plays in the nature? Remember that's the niche because the habitat is only the environment where it lives It's not the role it plays the niche has two components the job and the habitat Okay, so it's not these the answer is going to be a so I really hope that was useful I know it's a lot. I apologize that it's a long video, but there is a lot of content Unfortunately, I hope it was useful and I will see you guys in the next one