In what ways were therapsids adaptively superior to the amphibians and reptiles that preceded them?

First, we should have a basic understanding of each group of creatures: Amphibians, Reptiles, and Therapsids. Amphibians are a group of ectothermic (cold-blooded) vertebrates that generally live part of their life in water and part on land. Reptiles are also ectothermic vertebrates but are more adapted to living on land and include animals like turtles, lizards, and snakes. Finally, therapsids were a group of synapsids, which are mammal-like reptiles, and were the evolutionary link between reptiles and mammals.

One significant adaptive advantage therapsids had over the amphibians and reptiles was the regulation of body temperature. Unlike amphibians and reptiles, which are ectothermic, therapsids were likely able to regulate their body temperature internally. This endothermic (warm-blooded) regulation allowed them to maintain a constant body heat and therefore have higher energy levels, leading to increased activity and better adaptability to varying environments.

Therapsids had a more advanced limb structure compared to amphibians and reptiles. Therapsids' limbs were positioned more vertically under their bodies, which allowed for enhanced terrestrial movement. This posture allowed them to move more swiftly and efficiently on land, providing an advantage over the sprawling limb posture found in reptiles and amphibians.

The skull structure and jaw mechanics of therapsids were also better adapted than those of amphibians and reptiles. The jaw of therapsids, featuring differentiated teeth for biting and chewing, allowed them to process their food more effectively. Additionally, the therapsid skull had more advanced structures for better attachment of jaw muscles, increasing their jaw strength and allowing them to capture and eat a wider variety of prey.

Therapsids had superior reproductive adaptations compared to amphibians and reptiles. While most amphibians rely on external fertilization and aquatic environments for reproduction and early development, therapsids likely had internal fertilization and, in some species, may have laid amniotic eggs or even given birth to live young. These reproductive adaptations allowed therapsids to reproduce more efficiently and in a wider range of environments, providing them with a significant advantage. In conclusion, therapsids were adaptively superior to the amphibians and reptiles that preceded them due to improvements in body temperature regulation, limb structure and posture, skull structure and jaw mechanics, and reproductive strategies. These advantages allowed therapsids to survive and adapt to various environments, ultimately leading to the evolution of mammals.