Question

a. Ardipithecus ramidus has been classified as a hominid. What features support this? For this species, there are three traits from the chart above that make this species likely to be a biped when on the ground. You might need to use some of the features that your book has already filled in for you.

b. What does this mix of ape-like and more hominid-like characteristics, known as mosaic evolution, indicate about the lifestyle and behavioral patterns of Ardipithecus ramidus? Make sure to write about where this species could have lived and maneuvered in its environment.

c. If Ardipithecus ramidus is a direct ancestor to modern humans, what features would you expect the specimen immediately following it to have? Provide at least 2 features.

Answer 1

a . Ardipithecus ramidus is a bipedal organisms with more similar features linked to humans.

1. The skull and teeth of Ar. ramidus is similar to humans and it is the first evidence for its relation to the hominid family.

2. Ar.ramidus skull has cranial vault and cranial base, that occupies most of the skull and the righ side of the face. this feature is similar to the early hominins and even now, Apes are having this facial skeleton.

3. similar to early hominins, Ar. ramidus has complete forelimbs fossils records suggests that they are bipeds which is the distinctive feature of hominins. scientists earlier considered oligate bipedality as the distinctive feature possessed by the homonin lineage, followed by the skull and teeth development, but Ar. ramidus fossil records have proved it wrong and stands as the solid ancestor for humans.

b. Mosaic evolution and features similar to other hominids:

Mosaic evolution is the evolution of characters that takes place in the body parts or systems without more changes in the other body parts. Ar.ramidus is linked phylogenetically to Homo + Austraopithecus through their postcranial features, nonhoning canines and short basicranium. Short and broad central cranial base is similar among the three traits and there are little modifications in the petrous, tympanic and basioccipital elements which suggest that they are closely related.

They have survived in the deserts of Africa, mostly around Ethiopia. They were believed to have lived in the late Miocene and early Pliocene epochs in Afar depression. Fossil record analysis has proved that they have lived on the grassland with few trees. Their long, big forelimbs show that they have lived in the trees and had the capacity to climb up. They have survived mostly in the trees with nuts, fruits, and small mammals as its food.

c. There are more features that are similar to humans to suggest that they are our ancestors.some of them are :

1. They possess smaller diamond - shaped canines as that of humans.

2. Upright walking, a distinctive feature of human.

3. Their brain was small ( 300- 350 square centimeters) similar to humans.