Hence, to add to my previous post, you are entitled to use the designation "human" as an equivalent for "hominid". But scientifically spoken, I wouldn't prefer that. It is already difficult enough to get concepts defined straight and valid enough.<quoted text>
"- humans inherited technology from their ancestors, like homo Erectus and homo Habilis"
Erectus and Habilis...were humans too, just primitive humans.
As we know speciation is a gradual process: tiny genetic steps taken on by one in each generation.
Now, is it possible to say exactly when you became an adult and stopped to be a child? Was it at 13? At 14? Maybe 15? Or even 18? Even though adolescents exhibit growth spurts and there are remarkable moments, "tipping points" you may say, like girls having their first period (and boys their first wet dream), it is impossible to draw a decisive line. But we unmistakably can tell that a 20 year old man is not a boy any more (at least physically....) and a 12 year old boy not an adult.
The same applies to speciation: when does a new species emerge? There even are no remarkable tipping points here. Even decisive instances like genetic isolation are not traceable in the lineage. There is not a single line to be drawn. The only line drawn we know of in EXTANT species is genetic isolation. But this applies to the phylogenetic identification of extant, related species, not to the ancestral history of a single species. We can draw the line between extant species and relate that to their differences in genotypes. From this we know a few things. We know some factors in the genotype that strongly correlate with genetic isolation. Those factors we may use as well in determining phylogenetic differences in fossil finds.
HENCE, what may we expect form the perspective of evolution theory? We may expect it to be very difficult to differentiate between fossils. THAT is exactly what we expect from GRADUAL speciation.
And that's EXACTLY why palaeontologists have a hard time to classify fossils according to their species. Dozens of times there is debate among scientists whether a particular fossil specimen were to be species A or species B or belonging to genus X or genus Y. Homo Habilis belonging to the Pithecus genus? OR to the Hominid one? were Homo Rudolfensis and Homo Habilis the same species? Etcetera.
The difficulties of palaeontologists to establish a unambiguous taxonomy of species is EXACTLY what one might expect in the light of common descent through gradual speciation.