Absolutely fascinating
The way these animals function might
give us an insight to solutions to
major world problems.
We just have to understand them!
This webpage will give you an insight on the overall trends and reasons for development, evolutions and adaptations in the circulatory, respiratory, digestive, excretory, nervous, and reproductive system, as well as special adaptations across fish, amphibians, reptiles, birds and mammals.
Vertebrate Classes
Vertebrates are animals that at some stage in their life have a notochord, pharyngeal pouches, and a post-anal tail. They are unlike any other chordates because they have vertebrae (a small bones that forms part of the backbone), a cranium (the skull, specifically the part enclosing the brain) and an endoskeleton (an internal skeleton/framework of an animals that provides protection and support internally).
Fish are considered to be at the beginning of the complexity line. The amphibians are said to have originated from lobe-finned fish and they then "gave birth" to the reptiles. Birds and mammals are then at the end of the complexity gradient, mammals being considered the most complex and best developed class of all vertebrates.
Fish are limbless, cold-blooded animals who completely live in the water and have gills and fins. They include Lampreys, Hagfishes, Cartilaginous fishes (such as sharks), and bony fish (such as trout).
Fish are considered to be at the beginning of the complexity line. The amphibians are said to have originated from lobe-finned fish and they then "gave birth" to the reptiles. Birds and mammals are then at the end of the complexity gradient, mammals being considered the most complex and best developed class of all vertebrates.
Fish are limbless, cold-blooded animals who completely live in the water and have gills and fins. They include Lampreys, Hagfishes, Cartilaginous fishes (such as sharks), and bony fish (such as trout).
Amphibians are cold-blooded vertebrates that in their larval stage have gills and are aquatic, but later on evolve to be terrestrial and have lungs. They include frogs, toads, newts, and salamanders. They are considered to be the first animals that bridged the gap between aquatic and terrestrial, and are probably the first animals to have four limbs.
Reptiles are cold-blooded vertebrates that have a dry scaly skin and can be both in the water as well as on land, though they breath through their lungs. They include snakes, lizards, crocodiles, turtles and tortoises. They are considered the closest relatives to the dinosaurs and early avian species. They are part of a group known as amniotes unlike amphibians and also do not spend their early days in an aquatic environment. They are the first animals to adapt to life on land fully.
Birds are warm-blooded vertebrates that are oviparous (lay eggs) and can be recognised by their feathers, beak and wings, and they are typically able to fly.
Mammals are warm-blooded vertebrates that can be differentiated by possessing hair or fur, milk is used to nourish their offspring, and they typically give birth to live young/offspring. They are considered the most evolutionary advanced animals found on earth, and they include the largest animals on land with the elephant and in the sea with the blue whale.