Before that, some Australopith is ancestral to ergaster maybe or maybe not via a known early homo. The problem there is that there is a big jump from australopiths to homo, and it is quite possible that there was a lot of messy stuff going on during that period, so frankly I expect it to be possible some day to pick an asutralopith and say “this is the one” but not an early homo population with the same level of certainty (becasue we may well not even find it).

Which australopith is the one that, perhaps via an intermediate population, is truly ancestral to Homo? Starting with this question and working backwards through time, I think we are going to be stuck with “representative” mode but there will be a strong argument for one known australopith being the one. I predict it will be a robust (paranthropus) form from southern Africa that may or may not be known yet, but that’s just a … gut feeling, as it were.

But that will probably be the best we can do, and prior forms will all be more vague until we discover, if it is true, a single widespread species that can really be the only one because it IS the only one. That is unlikely to happen, but if we settle for a single widepread genus, then we may have a shot of identifying the lineage at that level. Something like Anemensis.

How many fossils do we have that are probably direct ancestors to humans? I just want to estimate how many actual links we do have, compared to those that are missing 😛

Another common misconception is something like “black holes are nasty vacuum cleaner like things.” In fact, if the moon shrunk down while keeping all its mass so that it became a black hole, life on Earth would be almost identical aside from slight changes in tides. A similar remark applies to if you replaced any other local body with a black hole (although if you did this to the sun it would get very cold).

Almost every area of science has these problems.

It’s similar to stories that get paleontologists in an absolute lather, calling paleontologists “archaeologists” and pterosaurs “dinosaurs”. Most people probably think of the former, in each case, as a special case of the latter. This is engendered, in part, because no commonly known term has been offered for that role — what is a generic term for somebody who discerns the past by digging stuff up?

Ultimately it’s probably a lost cause to try to get control of the term “dinosaur”, and the graceful thing would be to get used to it. There’s not that much difference, anyway, between ornithodiran and dinosaur, phylogenetically, by which I mean that the terminology could easily have been decided the other way. I’ve heard of “archosaur” and “hellasaur” offered as a substitute to include ornithodirans, plesiosaurs, and crurotarsans, but have seen no evidence that either has any traction.

There’s a real opportunity to introduce two new terms “last common ancestor” and “ghost lineage”, by contrasting each to “missing link”. Most people are terminally impatient with word games exemplified by attempts to reclaim “dinosaur”, but new concepts are like candy.

This cheap shot usually gets the creationist sputtering in an entertaining manner, and as a bonus sometimes puts another datum into the head of an interesting bystander.