Final answer:
Key characteristics of individuals around 1.2-1.4 meters tall, presumably discussing Homo floresiensis, include minimal sexual dimorphism, robust body build, smaller brain size, and bipedal locomotion with a unique gait. Differences from Australopithecus to Homo species encompass brain size, reduced jaw protrusion, and adaptations for tool use and bipedalism. Current criteria for classifying Homo species acknowledge the complexity and diversity of traits.
Step-by-step explanation:
Individuals who are approximately 1.2-1.4 meters tall could potentially be discussing Homo floresiensis, an extinct species of early humans. Characteristics of such individuals would include minimal sexual dimorphism, with males and females being relatively similar in size. The body build of these individuals would be more robust with thicker leg bones, compared to modern humans. Brain size for H. floresiensis was smaller, around 400 cc, yet this did not necessarily equate to lower levels of intelligence. Their locomotion was bipedal, but with a high stepping and slower walking speed, possibly due to having flat and relatively long feet.
In contrast to the Australopithecus, species in the genus Homo, such as H. habilis, show key anatomical differences including larger brain size (around 661-700 cc), reduced jaw protrusion, better dexterity for tool use, humanlike postcranial features, and feet fully adapted to bipedalism. The classification of a species under the genus Homo also considers criteria like the use of tools and a globular skull shape. It is important to note the limitations of current classification criteria, as there is overlap and diversity in traits that can challenge straightforward categorization.