we are starting with a new topic which has been recently introduced into our syllabus of neat and that is in the chapter of structural organization in animals they have introduced frog in our syllabus so that is what we are going to talk about the most common Indian frog is R tigrina this is the scientific name of our Indian frog these frogs are amphibians so we place them in class amphibia and amphibians are those animals which can live in water as well as on land so in water as well as on land the requirement of water is for their reproduction and that is why they always found closure to the water body many of times in the water body or closer to the water body and they are in philm cetta frogs which we see around us they are visible only during a particular season that is rainy season rainy season is the season when they breed that is the breeding season and during extreme cold and hot conditions they go into a state of reduced metabolism which is known as hibernation and activation and the reason for this is that they are polms polms means they are cold blooded cold blooded animals are those which cannot maintain their body temperature temperature the body temperature changes according to the outer temperature that means if it becomes very low say the temperature comes to four or five degrees the body temperature will come as close as four or five at this low temperature metabolism doesn't take place or does not work same situation happens if the temperature goes high that is during summer So to avoid these extreme conditions they go into summer sleep and winter sleep which are known as hibernation hibernation is winter sleep and activation which is summer sleep during this period they remain in that state where the metabolism is very very low before getting into hibernation and activation this Store Reserve food and they burrow in the mud and during this these periods the metabolism is very slow and they survive only on that stored food material which they have normally the frogs they are olive green in color their skin is olive green the skin is very slimy because it is a mucous membrane we will talk about the skin little later so they are normally olive green but they have the capability of changing their skin color this property is known as camouflage they can change the skin color and this property is also known as mimicry so they can camouflage this is called the mimicry so now when they are on the grass they appear green and when they are sitting on the bark of the tree their skin is going to be like little brownish so that they can easily blend in their surrounding if you look at the morphology that means how they appear from outside as I said the color of the skin is greenish to Brown so skin color don't dorsal and vental side is different the dorsal side that means which is visible to us from the top is olive green to Brown depending upon which surrounding they are sitting on and the ventril side is pale yellow so this is the ventril and this is the dorsal side so the skin color is is variable but most of the times we see them are little greenish the skin is moist and this is because they have mucus glands due to mucus glands the body is divisible into head and trunk so if we try to draw say a simple diagram to understand how the frogs are going to look so let us see the body is olive green from the top and we are very much familiar with the frogs which we see around us and here you see bulging eyes so this is the ey and here is the another bulge so again a pair of eyes the hind limbs let us draw the hind limbs here very big prominent hind limbs okay so this is our frog and body is divisible into the head and the trunk head and trunk they do not have neck and there is no tail in the adult frogs so tadpole or the larval stage will show us the tail or has tail but in adult frogs we don't see the tail now this is the four limb so they have a pair of four limbs four limbs are comparatively smaller and less stronger as compared to these hind limbs hind limbs are longer and stronger because they have to LEAP or jump that is why the hind limbs are very strong now these are the eyes so eyes are bulging eyes they have bulging eyes a pair of ice and here we would see Tiny openings which are the nostrils the eyes are very prominent and very bulgy now just behind the eyes there is another patch which is visible so there's a prominent patch which is visible here one is on this side other will be on the other side and this is tanum tanum is the eard Dr drum they do not have Pina so this is the ear drum Pina is absent that is external ear is absent so when we look at the Frog the body is divisible into the head part and the trunk part neck is not there and this is because they have to have a streamline body so that they can swim very easily in uh the water so to avoid that neck is not there hind limbs we can see are very very uh strong and longer the digits in the four limb there are four digits and the hind limb has five digits or hind limbs have five digits between these digits are the folds of skin so here there are these folds of skin which are known as webs so we say they have webbed feet so these FS they are the webs and help the Frog to swim so we can fill this these are the webs the folds of the skin male and female frogs can be distinguished easily that means they show sexual dimorphism in case of the male frog the first finger or first digit of the four limb on the ventral side not on the dorsal side on the ventral side has a Paddy structure I'm going to draw it here only so here there is a Paddy structure and this Paddy structure is known as the copulatory pad this is found only in case of the male frogs it is called the C [Music] ulatory pad or it is also known as nuptial pad this is found only in male frogs only in male frogs and its function is it is used to hold the female during culation again we will talk about this when we come to the process of fertilization which is seen in case of the frogs so this is one difference the second difference is in male frogs in this lower head region here in this region there is a flap which is vocal cord so the vocal cords are prominent in case of the male frogs not it is not there in case of female so these are the vocal chords so it is in the form of a pouch which is there and they make the croaking sound basically so male frogs will have this culator or nut nutal pad on the inner side of the first digit of the for Lim and there would be vocal sacks or vocal cords it can also be known as a sack vocal sack which is a big uh balloon like structure which create or which helps them make a sound and this sound is used to attract the females so this is the outline structure or what we call the morphology details of all these things we will take up later when we come to respiration we'll talk about the skin also so here we have just completed the morphology part of the Frog