Final answer:
Cetaceans, which include dolphins and baleen whales, are an example of mammals that have lost their teeth through evolution, with baleen whales evolving baleen plates for filter feeding instead of traditional teeth. Tooth loss in mammals is linked to dietary adaptations and can illustrate a broader evolutionary trend of morphological change.
Step-by-step explanation:
Many mammals have indeed lost their teeth throughout the course of evolution. A prime example of this is seen in cetaceans, such as dolphins and baleen whales. Cetaceans exemplify a significant evolutionary transition from land-dwelling creatures to those adapted for life in the aquatic environment. This group has undergone profound changes, including the modification or complete loss of teeth. While toothed whales still retain teeth for capturing prey, baleen whales have evolved baleen plates that allow them to filter feed, illustrating a loss of the classic mammalian dentition.
Dental evolution is a critical aspect of mammalian adaptation, responding to the need for processing different kinds of foods. Over time, certain species may lose their teeth entirely if they become unnecessary for their mode of nutrition. This has been the case with some mammals that have transitioned to filter feeding or those with highly specialized diets that do not require the mechanical breakdown of food using teeth.
Another aspect illustrating tooth evolution is that most mammals, including humans, are diphyodonts, having two sets of teeth over their lifetime - 'baby' and permanent teeth. This differs from polyphydonts, animals whose teeth are continuously replaced. Evolution can lead to modifications in tooth number, size, and structure, which is often closely tied to the animal's diet and mode of feeding.