Final answer:
The morphological species concept defines a species based on physical form and structure, utilizing traits like body plan and development features for classification.
Step-by-step explanation:
The species concept that characterizes a species by its body shape and other structural features is known as the morphological species concept. This concept focuses on the morphology, which is the form and structure of organisms, for classifying them into species based on their physical traits, such as body plan, symmetry, and developmental pathways.
Traditionally, animals have been classified based on their morphological and developmental characteristics, like symmetry, number of tissue layers, and embryological development. These physical traits are used to classify organisms that appear similar into the same species. However, this approach has limitations, as it does not account for genetic variation or the ability to interbreed, which are considered in other species concepts, such as the biological species concept.
In taxonomic classification, scientists also look for derived characteristics that are present in related organisms but absent from their last common ancestor, aiding in identifying speciation events. Although morphological features are important for understanding an organism's biology, they can be poor indicators of phylogeny due to evolution driving both convergence and divergence among species.