Mammals,birds and reptiles are fully adapted to life on land. Fish live in water and amphibians start their life in water, then live on land.
Vertebrates came first... all of those other creatures are vertebrates.. prior to the evolution of the spine (vertebrae) there were no fish, reptiles, mammals birds... nothing like them..
The five classes of vertebrates (fish, amphibians, reptiles, birds, mammals) evolved in the following order: fish appeared first, followed by amphibians, then reptiles, birds, and finally mammals. Each class adapted and diversified to exploit different environments and ecological niches over millions of years.
Amphibians were the first vertebrates that came out of the water. The first vertebrates that could live outside of the water though were reptiles. or class reptilia this was during the Carboniferous period.
A duodenum (Assuming this is what you meant) is the first part/section of the small intestine that is found in vertebrates. (Reptiles, birds, mammas, etc.)
The first class of animals to have jaws were the gnathostomes, which include all jawed vertebrates such as fish, amphibians, reptiles, birds, and mammals. Jaws evolved from skeletal rods that supported the gills in the early jawless vertebrates.
Plato Users: A. Amniotic Egg, and Dry Scaly Skin.
One is that the first reptiles (not dinosaurs!) appeared. The land during this peiod was swamp-forests.
The first land vertebrates appeared in the: Devonian
All land vertebrates (including humans) can trace their origins back to the first fish that began crawling on the land using their strong, jointed fins. Eventually, the fish became more adapted to dry land and became amphibians. However, these amphibians still laid their eggs in water, and their young were tadpoles that spent all their time in water. The first true land vertebrates were reptiles, who were born on land and spent almost all their time on land. A small group of these reptiles became warmblooded and started growing hair, so they became the first mammals. Mammals remained small until the extinction of the dinosaurs, when they were given more room to grow, diversify, and give rise to humans.
Reptiles were the first true land vertebrates because they were able to successfully adapt to terrestrial environments with features such as scales to prevent water loss, amniotic eggs for reproduction on land, and efficient respiratory systems for breathing air. These adaptations allowed reptiles to thrive on land, marking a significant evolutionary shift from their amphibian ancestors.
The first and most basic distinction is to separate them into mammals, birds, reptiles and amphibians. But, every species is different and in a species there can be subspecies with their own differences. So, there are as many differences as there are species.
The first vertebrates to come onto land were fish-like animals that developed lungs and could thus stay on land for extended periods. These evolved into terrestrial amphibians (although many amphibians require water in which to lay eggs, and some are aquatic).