0:01 Good evening all my dear favorite students. This is Dr. Anisha from Sri Chaitananya Educational Institutions. Once again welcome you all for our NEATE bridge 2025 courses for the exams of NEAT 2027. So here we are again starting with a fun-filled classes of zoologology where we are learning various topics that will be very helpful for you in your future classes for your actual neat examinations. All right. So we have done various aspects of zoolology, various points, various common common points which are going to be very helpful for you. You might miss them during your actual lectures or your actual classes. Yes. Yes. Yes. Good evening to all. But in certain cases you will find out that
0:47 these lectures, these points, these things which you're learning here right now will be very very helpful for the actual lectures for the actual classes. So let's start here again. Let's start the studies again. We have studied till the Okay. Okay. So many good evening today. So many. Thank you so much. I'm really overwhelmed with your um with your greetings. Thank you so much. Thank you all of you. Okay. So we were continuing the animal kingdom, right? So animal kingdom, the kingdom which contains all the organisms which have the characteristics to be called as an animal. Now the animal kingdom here we were studying about the various aspects of their life processes. How do they
1:34 respire? How do they move around? How do they circulate their blood as well as different type of body fluids? So we were discussing all these. We were discussing the reproductive system and here in the reproductive system again we have reached the point where we will be studying with the process of metamorphosis. Yesterday we have studied the reproductive system and in the reproductive system we studied about the process of fertilization different types of fertilization external internal fertilization and the development of the organism. Development of young organism in different type of animals. It can be of two types. It can be a direct development. It can be a indirect
2:19 development. Now in case of indirect development there is a presence of laral stages. The fertilized egg will grow into a larva maybe another stage called as pupa and then into an adult organism. Whereas in direct development we have seen organisms they directly come out in the miniature form of the adult organism. So where will you find out the direct organism? The example of direct fertilization or we can say the direct development can be seen in case of animals like reptiles, the birds where the fertilized eggs directly changes into the organism. Whereas the frogs they generate an intermediate state
3:04 called as the tadpole larvae. So that is a indirect development. So direct and indirect development we have studied. Now we are coming to the ways of indirect development which is called as metamorphosis. Now what is metamorphosis? Metamorphosis is the process by which gradually an organism becomes a larva and a pupa and then into an adult organism stage. Now what is these structures? This is an example of indirect development. In case of direct development, we have seen the examples. I hope you now understood what are the examples of the direct development. Now we are coming to the examples of
3:52 indirect development. In case of indirect development, there will be a stage of fertilized egg where the fertilized egg will change into a laral stage. The larvae will change into a pupa stage and finally it changes into an adult organism. All right. So how does that happen? The process happens the egg the egg ruptures. Egg comes out of its membrane and changes into a structure which is completely different from the adult organism. That is the basic difference between a direct and indirect development. In case of direct development, for example, in case of birds, if the egg ruptures, if the egg bursts, the organism that comes out, it
4:38 is the miniature form of the bird itself. But here what happens? This miniature form is completely different from the actual structure or actual characteristics of the adult. This is called as the larvae stage. The larva sometimes may have the many outer layers over their surface. They have different types of movement structures. Their feeding habit is different. They stay at a different place than the actual adult organism. So that is how a larvae is completely different in its structure in its physiological features than the adult organism. Similarly the pupa the larvae further
5:23 changes itself into another structure the caterpillar structure we can call it a pupa stage. Sometimes in some of the organisms there are presence of the various types of larvae. Different laral stages are present. Pupa stages may not be there always but in most of the organisms in most of the cases of the metamorphosis there is the presence of pupa stage and finally the pupa changes into the adult organism the adult organism changes as the insect having the wings they have these structures they have well-developed reproductive structures they have a different feeding habit as well as they live in a very different place than the egg or the larvae or the
6:10 pupa. So that is how the metamorphosis occurs. The metamorphosis is the gradual change from the fertilized egg into the larvae. Sometimes even in the pupa stage and finally changing into the adult stage. Why am I calling the pupa stage as the sometimes? Because not all the organisms not all the organisms that are showing metamorphosis will have the pupa stage. Maybe they have a single larvae stage. Maybe they are having multiple laral stage and no pupa stage. Or maybe they have larva as well pupa stage before becoming an adult. So these are the different type of metamorphosis
6:55 stages. Now metamorphosis based on these stages can be of two types here. what are the different stages of metamorphosis and what are the different types of metamorphosis. So metamorphosis here we can say see here it is the complete metamorphosis and another is called as incomplete metamorphosis. Now what is a complete and an incomplete metamorphosis? See here in case of complete metamorphosis just now we have read about the metamorphosis which is actually complete metamorphosis. Why is it complete? Because it is undergoing all the changes and all these stages of its life cycle. For example, the fertilized egg is becoming a larvae. The
7:43 larvae is becoming a pupa and the pupa is further changing itself into an insect, a complete fullgrown insect that is the butterfly gear. Okay. So these are the various stages it is going through for becoming an adult. All right. But what is happening here? See here in this case the egg is present. The fertilized egg further changes into a welldeveloped laral stages. These laral stages have different names even. But here in this case we are taking this laral stage as nymph. Okay. Different insects different organisms have different type of laral stages. So now here as an example we have taken an
8:30 example of larvae called as nymph. So egg becomes the laral stages. The laral stages do not undergo the stage of the pupa stage. Multiple laral stages are present. This is first laral stage, second laral stage, third laral stage. So they have multiple laral stages which finally changes into an wellgrown adult organism. So what is happening in this case the metamorphosis is not undergoing the stages of the pupa instead two three different laral stages will be there and then it becomes an adult organism. So such type of metamorphosis in which different stages might be absent are called as incomplete
9:17 metamorphosis. So there is complete metamorphosis and there is incomplete metamorphosis. In case of complete metamorphosis, each and every stages of development will be present like the fertilized egg becomes the larvae, pupa and then into an adult and each of these structures are different from each other structure- wise, physiology wise as well as different process wise. Whereas in this case in the incomplete metamorphosis there will be fertilized egg changes into two to three types of different laral stages with no pupa stage and then finally it becomes an adult organism. So such type of metamorphosis where one or more stages can be absent are incomplete
10:04 metamorphosis. Now which all organisms show the complete metamorphosis and which all other organisms show incomplete metamorphosis. Complete metamorphosis can be seen in the examples like butterfly. What else? The dragonfly. The dragonfly. These will show the complete metamorphosis. Incomplete metamorphosis. It is seen in cockroach, mantis, praying mantis etc. Even the
10:49 ant, bee, wasp, they all show the complete metamorphosis. Silkworm they show the complete metamorphosis. Whereas the cockroach, praying mantis and many other flying insects they show the incomplete metamorphosis. So these are the different type of metamorphosis. And I'm sure now you have understood what are the different type of metamorphosis are. Now we are moving on to the next part. What is it? It is the reproductive cycle. So now reproductive cycle is a very important part of the females of different groups commonly the mamalian group. Reproductive cycle is most important in the mammal females mammal
11:37 and females. Okay. So it is the characteristic feature characteristic features of mamalian female. characteristic feature of mamalian female. All right. So it is the characteristic feature of mamalian female. Now this mamalian female how it is performing these functions. They have two type of reproductive cycle. Two type of reproductive cycles are present. Now what are the two types of reproductive cycle? One it is the eus cycle. Another it is
12:25 the menstrual cycle. Two types of reproductive cycles are present in the mamal and females. One is the estro cycle. Another is the menstrual cycle. Easter cycle it is present in a group of organisms or a group of mammals called as nonprimates present in the nonprimate females. Whereas menstrual cycle is the reproductive cycle present in the primate females. They are present in primate females. Non-primate females. What are these organisms? Non-primate females are the organisms. First of all, we have to
13:10 understand the terminology primate. What is a primate? Which organisms are called as primates? Primates are nothing but the organisms organisms. For example, cow, dog, donkey. You can name any organism. Horse all of these are considered to be the non-primate organism. Then what are primate organisms? Because non-primates are these ones which we know commonly. So who all will be included as the primate organisms? Primate organisms are the ones which belong to the order
13:55 prima. One order is there called pimea in which different organisms are included. So order primator organisms they are the chimpanzeee, gorilla, oranutan, humans, gibbons. So we can see the organisms which we think to be our ancestors. So these are the monkey, chimpanzeee, gorilla, orangutan, chimpanzeee, gibbon, humans. All of these these whole group of organisms are considered to be
14:41 primator. So they are called as primates. These organisms are called as primates. The reproductive cycle in the primate females are called as the menstrual cycle. Whereas the reproductive cycle of the non-primate females like cow, dog, donkey, horse, any other organism other than this any mammal you can think of other than these primates are the non- primates. So these non-primates have a reproductive cycle called asus cycle. Now what is estress cycle? What is difference of the estus and the estress and menstrual cycle? So estus cycle is the characteristic feature of
15:29 all the nonprimeate female. It is the characteristic feature of nonprimeate females. And in case of non-primate females the endometrial shedding in case of the estress cycle does not take place. So what happens? Uerine layers uterine layers do not shed you are going to study them in detail when we'll be studying the actual topic here. So but before that estrocycle you need to know because that is a major difference between a primate and a non- primate in a mamalian female. So estrocycle in this case non-primate females they are present and they do not
16:16 shed the uterine layers. Utterine layers do not shed during the cycle. During the cycle, the uterine layers are not shed and there is a gap phase. A gap is present. A gap phase called an estrus phase present. An estus phase present after every estus cycle. So estro cycle basically it is commonly called as the heat period where the female produces larger amount of the body heat because of the higher amount of the hormone
17:02 called as estrogen. Estrogen is a thermogenic or a body temperature increasing hormone. The hormone level increases in this period which is called as heat period and this is commonly called as the breeding period in these animals. This is also called as the breeding period in this animals and in this case there are no shedding of the uterine endometrium layer and there is a gap present after each of the eus cycle. The gap is called as an estus phase. I know this might sound little confusing to you but these are again going to be very useful for you when you will be studying them in the actual classes. Now we are coming to the
17:47 menstrual cycle. Now how is it different? Menstrual cycle is present in all the primate females. So it is the characteristic of the all the primate females present in primate females. They are the characteristic of all the primate females. And in case of the primate females we can see uterine shedding takes place. Utterine shedding occurs. utterine shedding occurs and it is a continuous cycle without any gap. It is a continuous cycle without
18:35 any gap. All right. So this is the basic difference between an estro cycle and a menstrual cycle. In case of estress cycle, the female non-primate organism will be in the heat period because of the high body heat due to the hormone. And in case of the menstrual cycle as such throughout the cycle the level of the hormone changes as a result of which the body temperature also changes. The menstrual cycle shows the shedding of the uterine endometrium layer. Whereas in in estress cycle there is no shedding of the uterine layer. And eus cycle shows the phase of anistrus rare or anistrus days in which there is no
19:23 activity of the reproductive cycle. So after each estus cycle there is anistrus phase and then another heat period begins. In case of menstrual cycle, it is a continuous process and there is no gap present in between them. So these are the basic differences between estress and menstrual cycle. So here we have studied different patterns and different types of the reproductive system, different types of the circulatory system as well as the digestive system, nervous system based on which the whole of the animal kingdom is divided. Now we are moving on to the next part that is each and every film. We will be starting our discussion about the each and every filylm just in brief
20:09 in today's class. So we are starting with the phylm the phylm porifera. Okay. So here we are the phylm porifera starting with the phylm porifera. So phylm porifera it is. All right. I'm very sure you all have studied about the phylm porifera. We have discussed about the phylm porifera. Why are they called as pipherans? They are called as pipherins because they are porebearing organisms. They contain pore throughout their body. That is why they are called as peripherins. Now what are these pores? See if we see the organism structure like this. The
20:54 organism almost like this. This organism an example of the polyifera has multiple pores on its body. Multiple pores are present throughout its body. These pores help in their everyday function. These pores are useful for their everyday functions. These small pores are called as the osteia. These are the small pores which are present throughout their body are called as osteia. I am very sure you remember the meaning of pores because pores we have studied earlier also the word meaning of pores is holes or the
21:41 aperture. So the simple pores which is present throughout the structure of the body these are called as osteia. All right. So now moving on to the structure of the poreifera. How do we start studying each and every film that is going to be very important. See there are 11 filmm present and reading them or learning them by each and every point is a little tough job but there is a strategy to read them. How do we read them? How do we study them? While studying any of the film in animal kingdom, what we need to focus on is these basic points. We will divide each and every film in the basic
22:27 points which each and every film will have and we will compare them from one another and we will be easily able to remember them for long time. So we will start each and every point each and every concept or each and every characteristics of these fililem separately. Philemifera we will read there these points in case of the phylm cylindrates again we are going to study them in that way. So each and every film will be studied like these strategies so that if you remember the point sequentially you can just fill the blanks and you can easily remember you can easily identify the characteristic of the film. So let's start studying
23:13 here the peripheral the porebearing organisms. Now porebearing organisms what are their characteristics? The first characteristic is the habit. Most of the peripherants they are sedentary in nature. Habit means what are they look like or what are their characteristic like? What do they eat? What do they like? So these organisms habit is they are sedentary. The word sedentary means non-motile. It is also regarded as cescile. These are all same terminologies sedentary or sensile or we can say non-motile. So these are the
24:01 organisms which are sedentary in nature. We can say they do not move. We know all the animals move but these are the organisms which live at one place do not move around much because they are cesile or nonmotile in nature. Okay. So these organisms are sedentary in nature. They are present in which type of water? Present in warm water. They are not found in cold water. Why? Because it is a very simple concept. They are animals in cold water. These animals cannot survive. How will their enzymes work? How will their all the functions will work? So they all live in warm water. warm temperature or
24:49 warm water. They do not survive in cold or chilled water. They need warm water. They do not need even boiling water also. Neither it should be very cold nor it should be it should be boiling hot water. They live in warm water which has a temperature range of 15 20°C up to 30 35 38°C. So this mid-range of water temperature they can tolerate. Why? Because they are organisms which are animals. They live in a normal temperature. 25 to 35°C is the most ideal temperature. So they live in warm water. Their habitat. Habitat means the place of living, the place where they
25:37 stay. So where are they staying? They are living in water. So they are called as the aquatic organisms. Now in our first class also we have studied how do we divide or how do we differentiate the aquatic organisms. Some of the aquatic organisms can be freshwater organisms, some can be ter some can be in case of marine water organisms. So here we have seen the aquatic organisms can be freshwater forms. The freshwater forms as well as the marine water forms. Okay. Some of the organisms are freshwater as well as marine water forms. All of them are aquatic. They do not live in the land. They do not live anywhere else. They all
26:24 are immersed inside the water. They all are aquatic. Some are freshwater. Some are marine water. Now here we are again level of organization. Level of organization means we have seen how do their body function or what these bodies are made up of. Now the function of each and every structure each and every organ system for example the process of digestion the process of respiration the process of circulation how do we see these things happening inside them they are performing these functions with the help of different cells. So that is called as cellular level of organization. This is called as
27:10 cellular level of organization. Another is the body symmetry. Now what is body symmetry that we have studied. We can call an organism to be symmetric if we can cut them into two equal halves which passes through their midline or the central axis. In these cases if you see the diagram see the photo here you cannot cut that organism into two exact equal halves. There are no two equal halves present here also. You cannot cut them into two equal halves. So these organisms are not organisms which we can cut them into two equal halves. So these organisms are called as asymmetric
27:57 organisms mostly mostly they are asymmetric organisms. Okay. Next it is the body plan. Now what is body plan? How the body is arranged? That is called as the body plan. How the body is arranged? How the body has many of its function. So we have studied the body plan as the tube within tube as well as the blind sack. In this case since the body is made up of cells only or the primary functions like nutrition, digestion, respiration, circulation, everything is done by the cells itself. So it is called as cell aggregate body plan. It shows cell aggregate body plan. Okay. So cell
28:45 aggregate body plan is present because all the functions of the body are performed by cells only. So that is called as cell aggregate body plan. Germ layers. How do these germ layers react? What is this germ layers? We have studied the zygote divides. It divides into two cell, four cell, eight cell, 16 multiple cells. And finally three germ layers are produced. The outermost ectodorm, innermost endodm and the middle one is misodum. So three gem layers are present. But in this organisms three gem layers are not produced. They are very primitive organisms in which we will see only two germ layers. Now what are these two germ layers? One is ectodorm and another is
29:33 endodm. Since they have only two germ layers, they are called as diploastic. So these organisms are called as diploastic organisms because they have only two germ layers ectodom and endodm. Now cylum or the body cavity this is another one. Sylum I have told you if you remember will be present in the organisms with only three gem layers. Below three germ layers no true or body cavity will be present. So in this case what we see the colum will be present here. Now the cylom is body cavity a body cavity a cavity is present inside the body but it is not a true
30:21 because they do not have misodum. No misodum, no covering of misodum throughout the body cavity. No true sealom because to call a space cylum, it should be present between ecto and endodm and it should be completely covered with misodm. If you don't remember it, go to the previous of the videos where I have mentioned this. You will learn about the definition of cylum there. So cylum only it will be called if the cavity between ecto and endodm will be completely lined by misodum. So if no misodum is there there is no question of cylom present. So they are asylumate organism. They do not have
31:09 true they are asylum organism. So these are the important characteristics which are present in the phylm forifera. So see here how easily we have covered all the important characteristics of the film fora right now the habit the habitat level of organization cellular level body symmetry asymmetric body plan cell aggregate plan because all the functions are performed by the cells the gem layers diploastic two gem layers are present aomate no true cavity no true body cavity or true selom is present present so they are asyomate. So these are the important characteristics in a nutshell about the phylm porifera. Now
31:55 if they ask question any question related to the general characters of the phylm porifera is asked to you I'm very sure you are going to answer them very very well because these are the ones they are going to ask them. Okay. Now here we are starting with another important terminology or another important characteristic about the film pipera which is present in all the periphereral and the most important characteristic feature of all the periphereral that is this water canal system. The water canal system of the phylm piperum. So now we are starting with the water canal system. Now what is this
32:40 water canal system? Water canal system as you can see here it is a system which is made up of different type of pores in the body's structure. We know the name porifera. Porifera are porebearing animals. Now these porebearing animals they have pores miniature pores large number in their body all over their body. Now these miniature or these small pores or these holes present in their body gives them the name porifera. But what are the uses of these pores? You must have thought of it or no I don't know but you should be thinking about it what these pores are actually doing on their body. Multiple multiple holes or
33:29 multiple pores are present throughout their body. Now what is happening to these pores or what are the functions of these pores? With the help of these small pores, there are two types of pores present. These small pores which are called as the it is called as the osteia and one large pore it is called as the oculum. Many small pores are present. See here in the diagram many small pores are present which are called as the osteia and one single large pore is present which is called as the oculum and inside this space or this body cavity this is not a true cavity this is
34:14 just a space inside its body. Now the space inside its body is called as spongio seal. Okay. Now if we come to the pathway of water, what is the use of this pores? We will see now. Now the pathway of water if we see so the water enters through enters through osteia. Okay. The water enters through osteia. Now what happens the water then circulates throughout the parts of the
35:00 body cavity called as spongio seal. Okay. Water circulates water circulates in the body. Water circulates in the body which is called as spongil. Throughout the body the water will be circulating throughout the body. The water will be circulating. And next what happens? The water will be released through osculum through the structure called as oculum. Through the osculum water will be released out through osculum. The water will be releasing out
35:46 through osculum water exits. Okay. Through osculum the water exits. So that is how different ways the water is entering through the oa circulating in the spongio and is exiting through the osculum. This system is called as water canal system. water canal system is the most important characteristic feature of all these sponges or all the periphererals. All right. So this is the most important characteristic feature of all these sponges or all the periphererals. Now we are coming to another important part. The important part is which all organisms are considered or
36:32 which all organisms having this water canal system and why do we have this water canal system? What is the use of the water canal system? The function of the water canal system. Now we have understood the function. Now we have understood how the water canal system works. It enters through the osteia, circulates in the spongil, leaves through the osculum. Now what is the function of water canal system? The function of water canal system. What is the function of water canal system? Okay. So now you can think of the first function. What will be the first function? The first function will
37:17 be they will bring food inside the body. That is how they feed because they cannot move. So the water has to enter inside it. So they bring food. They bring food. It helps in the process of nutrition. They bring food into the body. Into the body. All right. That is their primary function. They bring food into the body. Next, what is the function? They bring respiratory gases. They bring respiratory gases. They bring the respiratory gases. Third, they help in
38:03 excretion. They help in excretion and they help in sexual reproduction. So these are the primary functions of these are the primary functions of the water canal system. So these are the primary function of water canal system because the water canal system helps in they bring the food into the body. They bring in the food. They help in bringing the oxygen dissolved oxygen inside the body cavity. They take out the carbon dioxide or they help in the process of excretion and also helps in the process of sexual reproduction. How do they help in sexual reproduction?
38:50 They bring sperm or the male gamut from another organism into a different organism's body through this water canal system. So these are the different functions of water canal system in these sponges which are the most important characteristic feature of all these sponges. If you have not written it, write it down. These are the most important characteristic of water canal system which is the most important part of these sponges. Now we are here the examples of the sponges. Now what are the examples of the sponges? The examples of these sponges if you see what are example we have seen. See these are the examples very simple examples two or three examples. There
39:35 are many examples of the peripherence or the sponges. But we are going to discuss here about few of the examples which is important from the point of view of your exams. So first it is the cycle commonly called as kyifa also called as earn sponge. also called as ern sponge. These organisms we have seen earlier also. So these are ern sponge or cyclon or scifa. These are freshwater sponges commonly called as the freshwater sponges which are spongila scientifically known as spongila. Freshwater sponges
40:23 scientifically known as spongula. And these are commonly known as bath sponge scientifically known as you spongia. So these are the organisms which you are going to study for your exams. These are the examples given in your textbook. So these are earn sponge, the freshwater sponge and the bark sponge. So these are the different type of examples of the film porifera. In the next class we will be studying about other film also comparatively in small details and about their examples. So here we are again. Thank you everyone and keep studying keep doing well in your exams and stay healthy. Thank you.
