in this video we'll be covering part of B 4.2 on ecological niches and we'll be focusing on nutritional niches so when I say a niche what I'm referring to is an ecological niche and that is the role that a species plays in its ecosystem and that can depend on a few different things it could depend on what it eats and how it gets its food it could depend on its zone of tolerance and that's because the zone of tolerance can determine what kind kind of habitat it can utilize and finally it depends on how it interacts with other species in the ecosystem so we'll be talking about a few different niches here I want to go over some keywords that will help you remember these other terms right so obligate means like obligation you have no choice facultative refers to kind of like having a choice at least that's how I like to think about it aerobic means with oxygen and then anerobic without oxygen so obligate aerobes are organisms that must have oxygen okay so this is going to be all animals and all plants okay all plants need oxygen as well obligate anoes are things that cannot be exposed to oxygen they can only live in anoxic environments okay so this is like the bacteria that causes tetanus or methanogenic Arc bacteria okay those must be in Anor robic environments unlike the bacteria that live on our skin they're constantly exposed to oxygen then you have the real weird ones these facultative Anor robes they can thrive in both um oxic or aerobic or anerobic or anoxic environment so I've included these terms here and you're going to find that they're used interchangeably which is why I put them in here so oxic refers to aerobic and anoxic is the same as anerobic they mean the same thing but these are going to be things like yeast or eoli that they will do different things in those environments but they can utilize both of them so you'll often hear people from different branches of biology referring to the same organisms by a different name so some like cell biologists might call these organisms autot troes they produce their own food and some e olist might call them primary producers this is the role that they play in an ecosystem but these are just names for photosynthetic organisms okay so photosynthetic organisms can include things like plants algaes and even different types of photosynthetic procaryotes like bacteria and what they all have in common is this process of photosynthesis and that is turning light energy or solar energy into chemical energy in the form of things like carbohydrates okay so again it's not just plants it also includes algae and some bacteria unlike autot trops that can kind of produce their own food heterotrofos are organisms that must eat their food they are consumers not producers now all animals are heterotrophs and most of them have what we call holozoic nutrition not all of them but most of them and that means that whole pieces of food are eaten and are digested internally so let's say I'm going to eat an apple okay I'm going to put that food into my mouth and then it's going to pass through my gut and a few different things are going to happen one of which is digestion okay so we have ingestion which is eating something digestion is the chemical breakdown uh into smaller molecules okay now I'm also going to be able to absorb some of the those smaller molecules so into my bloodstream we're going to get absorption of some of these smaller molecules not all of them are going to be able to be digested and absorbed however so the leftover bits of food or molecules that cannot be absorbed are going to pass out through the anus if it has an anus as waste okay and so we call that egestion the one word that I haven't touched on yet is assimilation that that means becoming part of the cells and tissues so again we have ingestion digestion absorption assimilation would mean using that in our cells and then egestion of any waste that cannot be digested or absorbed so heterotrophs things like me autot trops things like algae what about a miot tro I love this word because it's exactly what it sounds like it's a mixture these are organisms that can gather nutrients and energy in uh both autotrophic and heterotrophic ways so this means that they're going to be consuming things in addition to producing their own food using photosynthesis now we have a couple of different types we have obligate miot tropes that means that they must use both methods and then we have facultative one method or another depending on what's in available in the environment so this ugina may choose to use photosynthesis if it's nice and light okay and it can get plenty of sunlight and the temperature and everything is just right but it may choose to be heterotroph between Form and Function what adaptations do things have that make them successful in their environment so we're going to take a look at something called a sapot trro now sapot tropes are a type of decomposer so decomposers can either be saprotrophic or they can be um considered to be detritivores detritivores are things that digest matter internally so what we were just talking about like holozoic nutrition all right now Sapar tropes cannot do that they digest matter externally and in fact that's the big key word you should remember here with um separat tropes is external digestion so they're doing the same thing they're they're using things like enzymes to break large molecules down into smaller ones and they then absorb them it's just that's happening on the outside of their bodies so things like this fungus and some bacteria what they can do is they can spray digestive enzymes on things those enzymes break down those large molecules and then this fungi can absorb the the results of that digestion those small molecules okay so um still a decomposer just a different mode of nutrition now one of the groups that shows a lot of variety in its nutritional mood mode are those AR so this may be a little bit of a review for you AR is one of the three domains of life it's a procaryote um but it's actually more closely related to ukar than it is to other bacteria but anyways this is what we're talking about here and these AR have three different ways to get their energy so the Gathering of energy is one of the functions that all living things have in common these just have some interesting ways of doing it so they can be heterotrophic which means that they're consuming things they're getting their energy from other organisms some of them are phototrophic so absorbing light energy they're doing photosynthesis and others are chemotrophic so they're oxidizing inorganic chemicals for their energy and so there's just a lot of nutritional uh modes represented here in this group um to keep an eye on