Considering their age, we know a lot about Hominins. This is due to our ability to recreate the world in which they lived. Scientists analyze anything found amongst the remains, and often this shows what Hominins ate, the tools they used, and sometimes what killed them. Examining the depth the remains were found at and where they were located geographically can, along with dating techniques, give insight as to when and where particular Hominins lived. Finally, by using current technologies, computer reconstruction of the world as it was when they lived can detail further how they might have lived. Using these methods, anthropologists have shown that Homo erectus crafted hand axes and were omnivores, and endocasts show that this species had the ability to communicate vocally due to the size of its Broca’s area. Thus, as far a general knowledge goes, we know a great deal about Hominins. However, when the subject of their relationship to modern Homo sapiens comes about, there is a grey area.
Sadly, we will probably never be able to say with one hundred percent certainty the exact path evolution took to get to humans, nor know which ancestor was the evolutionary link between human and ape. Yet, as we find more fossils, and enhance technologies, this picture will become clearer. Nonetheless, which species slowly evolved into the next and how those slowly led to the modern Homo sapiens though, that is a riddle that may never be solved. What we have already pieced together can be seen below.
While we are relatively sure about these lineages, we know little about how all of them connect together, and even less about how the outliers factor in; this will take many more years of research to tease out. Nevertheless, in my opinion, the clues left to us by the past do indicate that we are indeed descended from Hominins.
Another reason we may never be able to figure out exactly how Hominins evolved into modern Homo sapiens is that fossils and theories must be validated; frauds do happen. A prime example is Piltdown. This hoax was widely accepted in the scientific community until it was disproven by Carbon Dating. This lead concurrently discovered real Hominin fossils being discredited. More negatively, the hoax caused the public to once again called evolution into question. On a good note, scientists did learn to be more scrupulous, especially with big finds.