 Assalamu alaikum. In today's lecture, we are going to talk about the animals. Animals are the most important part of the ecosystems, of the biospheres. Animals are placed in a specific kingdom, in the five kingdom systems called the animal kingdom. In this group of organisms, we categorize some specific group of living organisms, which are eukaryotic, which are multicellular, from very simplest sponges to very complex mammals, as complex as the human beings ourselves. Animals, they are highly adapted to their environments. Because they are the heterotrophs, that is, they have to obtain food from the environment. They have to depend upon the producers and sometimes other organisms, the other animals that is the consumers, for their food source, they have to adapt to specific types of environments for acquiring that energy and for reproducing themselves, to continue their race. Animals are widely distributed in almost all types of habitats. Animals are present in aquatic habitats, in ponds, in lakes, in oceans, in seas. They are present in all types of terrestrial habitats, like the forests, almost all kinds of forests, in the freezing cold, in the very very hot deserts. Animals are widely distributed. Even they are present in the air. We know the birds. Birds are the animals, which live for some time on the trees, which live for some time in the air, that is, most of the time they are flying inside the air and finding their food or maybe finding their prey, if they are carnivore animals. Animals are the very important parts of the food chains and food webs. We know that animals, they are heterotrophs and they are consumers. They have to consume different types of producers, maybe sometimes plants, maybe sometimes algae, sometimes maybe some other animals. So, animals are of various kinds. There is a huge diversity of animals present on the planet earth. They are eukaryotic, that is, their cells have a true nucleus. Animals consist of eukaryotic cells. They are heterotrophic. They rely on the organic carbon source. The carbon, which is provided by the producers in the ecosystem or maybe by other consumers, which are the herbivores or the primary consumers. So, animals are present at every level of, every trophic level of the consumers. Animals, they may be independently living or they may live as parasites in or on the bodies of other organisms. We know that the deers, the lions, the rats, the moles, they live as an independent organism. They may make the groups and families. There are many other animals, like roundworms, they are also animals, and they live inside the intestine of human being and some other animals. There are some other types of animals, which live on the bodies of other animals and we call them ectoparasites. For example, the ticks and mites, which live on the bodies of other animals and we call them ectoparasites. For example, the ticks and mites, which lives inside the hair that is on the skin of the cattle. So, ticks and mites, they are ectoparasites that if they are living on the bodies of some organisms, other organisms, animals or maybe sometimes, plants. So, animals are very, very important for human beings and for the ecosystems, for different types of ecosystems present on earth because they makes very important part of food webs and the food chains. For example, if the herbivore animals are not present in an environment, then the plants may grow to very, very high extent and this imbalance may harm the ecosystem. If the carnivores are not present, then herbivores may increase to that extent that they eat upon all the grass and the plants of the ecosystem and ultimately, they will also die. So, they make a natural check and balance mechanism inside the environment. Now, we talk about the diversity of animals. Animals are present in diversified habitats. They are present almost everywhere. They are widely distributed. There are two major groups of animals called invertebrates and the vertebrates. All the animals are categorized in either invertebrates or vertebrates. Invertebrates are the organisms who do not have a vertebral column. Actually, we say invertebrates do not have a vertebral column and the vertebrates, the organisms, the animals who do have a vertebral column and their nerve cord, the nervous system is running in that vertebral column. Animals, they are wild. If they are living in their natural habitat, they are wild. We call them wild animals. Animals are domesticated. That is, if we keep them in our homes or we keep them in our farmhouses, they are domesticated. For example, we keep pets and we keep some animals. We keep some dogs. So, they are pets. Some other people actually culture them for their personal or commercial purposes for getting eggs, milk or some other products. For example, people keep the hens in the cocks. They are also kept for beauty. Beauty of the nature. For example, some people do have peacocks in their houses. Some people keep the animals like the beautiful animals like the pheasants in their house, which are very beautiful birds. Animals could be kept into a captivity or a controlled habitat. For example, we know that we actually grow animals in the zoological gardens and in the safari parks. Zoological gardens, which are commonly known as the zoos. For example, we have a zoo in a very good big zoo in Lahore called Lahore Zoo. There is a zoo in Islamabad. There is one in Karachi if we talk about Pakistan. And there are very big zoos in the world. Zoo is an environment where the animals are kept in a specific environment which is not very actually near to their natural environment. And animals could also be kept in the environments which are more near, which are more close to their natural environments. We call them safari parks. There are big environments. There are big areas, huge areas, in which we try to create an environment which is closer to the natural habitat of that animal. We call them mostly safari parks or sometimes the national parks. Pakistan do have many national parks. One of these is very important one, the Ayubia National Park in the Khabar Pakhtunkha area, which have lot many animals.