Final answer:
The statement that an animal must be muscular and lean to be considered meaty is false; the term can include the presence of fat. Evolutionary changes in the skeletal system for land animals included placing limbs under the body and rotating the femur and humerus for efficient forward motion.
Step-by-step explanation:
To answer whether an animal must be muscular and lean to be considered meaty, the response is False. The term 'meaty' can refer to an animal that has a significant amount of muscle tissue, but it can also include the presence of adipose (fat) tissue which is not necessarily lean. In fact, some of the most valued meats for consumption have a mix of muscle and fat, such as marbled steaks, where the fat adds flavor and tenderness.
When discussing the evolution of the skeletal system as animals transitioned from water to land, several changes took place. One significant change was the placement of limbs under the body, which allowed for more efficient movement over land. This resulted in decreased adductor muscle size and a more pendulum-like motion for walking. Furthermore, the rotation of the femur and humerus in a way that pointed the ends of the limbs and digits forward, rather than to the side, was another adaptation that promoted efficient forward motion.