Final answer:
Amphibians are early tetrapods with moist skin and a life cycle that includes a larval stage, while amniotes possess a waterproof skin, a terrestrially adapted egg with amniotic membranes, and a wider range of habitats due to these reproductive advances.
Step-by-step explanation:
The main differences between typical Carboniferous amphibians and amniotes are significant in their adaptability to land and reproduction.
Amphibians emerged as the first true tetrapods over 400 million years ago and have a unique life cycle with an aquatic larval stage that metamorphoses into a terrestrial adult.
Their skin is moist, allowing for cutaneous respiration, and they lay shell-less eggs that require a moist environment to prevent dessication.
In contrast, amniotes which include reptiles, birds, and mammals, developed a terrestrially adapted egg protected by amniotic membranes, allowing them to lay eggs in drier environments.
This adaptation is coupled with other features such as waterproof skin, keratinized structures, and a unique skull structure in diapsids, which includes crocodiles, dinosaurs, birds, and modern reptiles.
Amniotes' ability to reproduce on land was a revolutionary adaptation that led to their wide dispersal and prevalence.