Hey guys, welcome back to a new video by Biology with Zhang Xuan. So today, we are going to start off the series with the IGCSE Biology 2023 to 2025 and 2026 to 2028. So this is a reduced study technique and a new series just to change the way how my old videos work so that it is more relevant, more concise and straight to the point. We are going to start off with chapter 1 today, Characteristics and Classification of Living Organism. The content of today we are going to go through is the introduction and what is new.
The second part will be the characteristics of living organism, concept and uses of classification system. features of organisms and lastly a summary okay so the introduction today so this is a renewed series of the previous uh full topicals igcc biology series that done so there are key things that i would like to share in with a newer study technique is that i would like to give a more comprehensive explanation with clear concise towards the syllabus and you just need to know what is required from here and then you are good to go so this there will also be a mind map and then this is how i'm going to start to train you to use different study techniques to gauge not just in your secondary education but progressing towards your tertiary education okay let's move on to the mind map so today we are going to do the chapter one okay which we have three things which is the characteristics of living organisms the concepts and uses of classification systems and the features of organisms okay so what do we know about characteristics of living organisms characteristics means like what do they do as an animal or as a living organism. So it's able to move, it's able to respire, it's able to excrete. These are examples of characteristics that we need to know. Then the concept and uses of classification system.
There's a lot of things in classifying animals, not just by just differentiating them one by the features and everything. In a more comprehensive way, biologists have learned ways to use DNA. to classify them to different kinds of species because genus and species now is the scientific name is how are we going to differentiate and their similarities, accurate similarities to them and their previous ancestors, okay? And we're going to learn more about this. And then lastly, features of organisms.
So living organisms, we have the mammals, we have the five kingdoms, we have the prokaryotes, we have the bacteria, the viruses, the... the insects so this will be further explored in features of organism okay so let's move on to chapter 1.1 characteristics of living organisms so let's see you have learned this before mrs grant have you heard of this term yes you do so you have heard this probably in year seven or even earlier than that so what does mrs grant mean means is the movement respiration sensitivity, growth, reproduction, excretion, and nutrition. So what is a movement?
Movement is an action by an organism or part of an organism causing a change of position and place. Means it has moved to somewhere. It's not just static, but it's moving. Then we have a respiration. Respiration is the chemical reactions in cells that break down nutrients, molecules, and release energy for metabolism.
it is for the purpose of metabolism and giving energy but we always think that respiration is breathing no this is not such thing so you have to find out more soon why respiration is not breathing okay sensitivity sensitivity is the ability to detect and then response to changes in the external or external environment basically by stimuli whenever something hot touches you you immediately create a sensitivity, right? Moving away. Then we have growth. Growth is a permanent increase in size and dry mass.
We all grow. We all grow at some certain parts and different moments of it. So growth is a part of a living organism. Reproduction is the processes that make more of the same kind of organism.
So when you breed new children or new animals, They are a form of reproduction because they can replicate. Excretion is the removal of waste product of metabolism and substance in excess of requirement. Anything that is a waste product, toxic, they will leave from our body.
body okay and lastly is nutrition they are able to take in materials as like for their diet and then to make sure that it can function for the remaining characteristics okay Alright, next one, concepts and uses of classification system, chapter 1.2. Alright, so we need to know that organisms are classified into groups by the features they share. Because whenever we talk about features, right, features is like what is observed, what is observable from like a distance. You can see like, how does this animal behave differently? How does this animal move differently from another organism?
So they can be classified by their features. And species. You need to know this definition.
This will be asked in exam. Species are a group of organisms which can reproduce to produce fertile offspring. It means that species, they are able to continuously reproduce. And then the generation continues like that.
So you have to know the exact definition for species. Then we have a sequence of classification. The kingdom is the largest, like the animalia kingdom.
All right. Then we have the phylum, the classes, the order, the families, the genus, and lastly, the species. So the binomial system of naming species is an internationally agreed naming system in which the scientific name of an organism comprises two parts, which is genus and species. So what do we know about genus and species? Have you heard before of Homo sapiens?
Homo sapiens are humans. But if you have seen how... scientists write Homo sapiens is where it has a capital H and a small s. So this is the format of writing.
Genus must be capitalized and the species must be non-capitalized. So the genus is a yeah. All right.
So they will have repeated. It's the same thing. Then the classification of organisms helps show the evolutionary relationship between them.
So scientists also use the DNA-based sequence to help classify organisms. discern so this is the key thing that we talk about the current classification system unlike last time we've used anatomy morphology now we use dna why because dna is accurate dna we can compare how similar it is and how accurate it is from now to the past then they can relate because the dna is passed down okay so that is how we classify by that evolutionary relationship which is their ancestors then the similarity of a dna chain show how closely two related other organisms are so in the end this is how we differentiate how we compare okay this shows the muskies this shows the muskies are visible features to classify organisms they give you two choices of two features maybe it can be more or follow the one that applies each option leads to another option until the organism is narrowed down to its genus and species so sometimes you can give you this is found in paper two or the multiple choice question or paper four in the structured question. So you can see the difference is that they always give you some features.
Then if you see the features are correct, it's usually very easy to spot. Then you move on to the second one. Then to the third one.
Then you find out which is the most best suitable answer. And then if it's for the paper four or the structured answer question, they will give you all these kinds of pictures. ask you to compare by their features that they have okay so the next one is the features of organisms chapter 1.3 so the features of organism you have the five kingdoms here five kingdoms you have the animals plants fungi prokaryotes prototips and these are like the five luck so what you have to know here just know that and you just need to know what are animals really animals can be like cat ladybird mute plants it could be any cactus, oak tree, any common plants that we see.
Fangai is a type of mushroom but of course again they can spread spores and then like yeast and mushrooms are one few examples. Prokaryotes in a way is bacteria okay so like salmonella, E. coli, prokaryotes and protocysts. Protocysts are single-cell organism with nucleus such as a mooeba.
So all animals in general are multicellular it contains a nucleus but no cell wall or chloroplast this is only applicable in plants and it only feeds on organic substances by made by other living things so the next one is vertebrates vertebrates are animals with a backbone we know that So mammals, they have fur hair on their skin, they have an external ear and a mammary gland. Reptiles, they have thick, dry, scaly skins, usually four legs. Fish, they have wet scales, they have streamlined body shape, external fertilization. fertilization and they use gills to breathe in. Amphibians, they are smooth and they have a moist skin.
They of course give out soft eggs. Gills and lungs can live land or water. They can breathe both conditions and most have four legs.
Birds, feathers, they have feathers. They have a constant internal body temperature, hard eggs and internal fertilization. So these are how they look. You should have known some of them already.
So this is more of a recap if you get this. Arthropods. Arthropods, something new here, so it's organisms that do not have a backbone, or we call it invertebrates.
So they have an exoskeleton in common, and jointed legs and segmented body. So one example would be the crustaceans. They have an exoskeleton, one pair of compound eyes, and they usually have 10 to 14 legs.
Arachnids, they have a cephalothorax, which is just basically the same thing, it's part of our throat. Then in humans, and there are four pairs of legs. Maripods, they are segmented.
body, 10 pairs of legs, one or two on each segment. And insects have three body segments, three pairs of jointed legs, one pair of antennae, and one or two pairs of wings. Okay, something like this. Just, you know, I think the key part here is to know how many legs they have. Okay, so something a bit, uh, not a good start, but like, yeah, you do have to know how many legs they have.
All right, classification of plants. This is a very famous famous questions that they can ask in exam. So let's see. So we classify plant kingdom into ferns and flowering plants. And in flowering plants, we have a non-flowering plant also, okay, which are ferns basically.
So ferns, they do not produce any flowers or seeds. They are plants with roots, stems, and feathery leaves that are reproduced by spores. In flowering plants, they have roots, stems, and leaves, and they reproduce sexually or sometimes asexually also with which they require a parent, and then the seeds are reproduced inside an ovary in the flower.
Okay, then, important. Monocotylodon and dicotylodon. So, you need to know, at least do, what they have and what dicotylodon has. So, monocotylodon have one cotylodon, parallel veins, have a long narrow leaf, three flower parts, and a scattered vascular bundle. So, the powerful dicotylodon.
We have two cotyledons, branching veins, broad leaves, four or five flower parts, and a ring vascular bundle. Alright, then lastly, we got viruses. Viruses, they are not part of any classification system.
As you can see, that virus does not include. Why? Because it is not a living thing.
It doesn't have a nucleus. It doesn't have a mitochondria. It doesn't have a ribosome. It only has a genetic material and then a protein code. Okay.
Okay, so that's the reason virus is not actually a living thing, but it requires to live on a host, means like somebody. Okay, then it can grow and replicate. Okay, so that's it in summary. Just know whatever is in the mind map. The mind map is shown here.
Just basically understand what are the characteristics that Mrs. Grant, the concept and uses the classification system. Like they need to use the. DNA to find the evolutionary relationships and the features of organism. We talk about the five kingdoms, the vertebrates, the arthropods, then the viruses in the end.
OK, so do familiarize with this first chapter. It isn't that heavy, but this is a start to anything. So I hope you enjoy this video and I hope to see you guys in the next chapter.
Bye bye.