So, there are are three different classes of chordates are given to us, along with eight different characteristics of the living beings, and we have to find the best option to be in the right place.
Fish:
They are chordates, also called as "L.Piscis". It is more obvious that fish are those chordates which are living inside the water medium, as they are characterized by the following features, as given below:
Spinal cord:The spinal cord provides the basic and most pivotal support to the living organism to move from one point to another.Gills in adults:Fish are characterized by gills inside there body, as they are able to extract the optimum amount of oxygen from the water medium.Scales:as some of them have while others have scale free bodies.Ectothermic: They are cold blooded,which means they are ectothermic in nature.Metamorphosis: While, the growth of the fish happens in a sequence or series of stages. As, it all starts from a small egg going towards a more matured form of living organisms.External fertilization: The reproduction process inside the fish includes both the external fertilization. Which means that the female releases its eggs in the outside environment and then the male inseminates the number of eggs. While, there are some species which posses the internal fertilization features in there bodies.Species of fish: Sharks, lobster, Marlins etcReptiles:
The reptiles are mostly tetra-pods excluding the snakes which crawl over the surface of land.As they are more similar in features to the amphibians, as they are some times studied under the same class of research and studies named as "herpetology". As, the reptiles have a very circulatory system, along with which reptiles includes the crocodiles,snakes, turtles, and many other species having the following features, given as below:
Lungs in adults: As the reptiles are characterized by lungs when there body is all grown up(adult form). Lungs are sacks of air, found in the abdomen region of the body. The lungs are found in pair inside the specie body, which is basically operates for oxygenation of the blood.Spinal chords: Like all other chordates the reptiles have a strong and supportive spinal chord found inside there body. As it provides the reptiles with the basic framework to arrange the different parts or organs of the reptile's body.Scales: The reptiles body is comprised of the scales all over it, as the reptiles mostly live in harsh or severe forms of climates. While, the species like turtles have the hard covering to protects it body from any predator inside or outside the body.Amniotic eggs:The reptiles have the characteristics of having the outer covering its embryo found inside the sack. And that's the reason reptiles are some times called as the amniotes. The amniotes have there embryo being protected from the predators and other animals.Ectothermic: They are dependent upon the outside source or the different factors of the environment to get the optimum level of heat to drive the different functions of the living body. And that's why they are also referred to as cold blooded living beings.Species of reptiles: Crocodiles, snakes, turtles etc.Amphibians:
They are always termed as they living beings with dual nature, or the animals that can live both inside water and on the land. As they are included inside the category of chordates having the following features:
Ectothermic: They are the cold blooded animals having there dependence on the outside environment to obtain the optimum amount of heat to maintain there body temperature.Gill in some of the adults and lungs the most prominent: Â The amphibians have the dual nature to live both inside the water and roam around the surface of the land.Because, the amphibians have the lungs to breath or make the optimum amount of oxygenated blood to support the various body functions. While, the gills are found on the outside of the living creature body, which supports the living body to breath inside the water.Metamorphosis: The growth of the amphibian's body occurs indirectly as there is the metamorphosis to support the development of the animals body. The process of metamorphosis involves the growth of the living beings from a very less developed form into a adult form of living being.External fertilization: The amphibians go through the process of external fertilization inside the water medium, as the organisms lacks features to produce internally or inside there body.Species of amphibians: Frogs, toads, and salamander etc.
