When did our hominid ancestors first start using tools? This is a fascinating question of human paleontology, and it is also difficult to answer definitively. There are two basic reasons for this difficulty. The first is generic to all paleontology – our knowledge of when something emerged is dependent upon the oldest specimen. But the oldest specimen is likely not the very first emergence, so dates are frequently being pushed back when yet older specimens are discovered. Often scientists will say that something is “at least” a certain age old, knowing it could be older.

Tool uses specifically, however, has another challenge – we can only really know about tools that survive and are recognizable in the record. If early hominids were using wooden tools, for example, it would be very difficult to know this. If they were using unmodified stones this would also be difficult. We could potentially infer such use if the results were visible in the fossil record, such as marks on the bones of prey, but that can be difficult.

So when we talk about the earliest evidence for tool use in our ancestors we are talking about crafted stone tools. The oldest known stone tools date to 3.3 million years ago, at the Lomekwi 3 site in Kenya. At this time there were Australopithecines around but not yet any members of the genus Homo. H. habilis and H. rudolfensis date from 2.8-2.75 million years ago.

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One of the things I like about following paleontology news is that new evidence can just be discovered, and sometimes these new pieces to the puzzle can significantly change what we think about past life. One such controversy I have been following for a while is whether or not small specimens of Tyrannosaurus rex-like dinosaurs represent juvenile T-rexes or a separate smaller species of theropod dinosaur. A new analysis of a nearly complete Nanotyrannus specimen has definitively resolved the debate – Nanotyrannus was a separate genus.

There are several layers of context that make this story more interesting. First, why was it so difficult to determine if different specimens were the same genus or not? This is not just due to having incomplete specimens – even with complete specimens, this can sometimes be tricky. Will all unknown species paleontologists need to determine if morphological differences are just within-species variation, different growth stages, or even male-female differences. Are we looking at two different species or genera, or a male and female of the same species?

This can be particularly difficult with dinosaurs, because many dinosaur species grow very large over a long period of time. Further, they can undergo significant morphological change as they grow. Another similar controversy, for example, was between Triceratops and Taurasaurus, the latter being larger and with a slightly different frill. It was considered plausible that Taurasaurus specimens were just older Triceratops, and therefore bigger and with age-related changes to the frill. With further specimens and analysis it is now considered that Taurasaurus is its own genus within the family Ceratopsidae.

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Humans are dramatically changing the environment of the Earth in many ways. Only about 23% of the land surface (excluding Antarctica) is considered to be “wilderness”, and this is rapidly decreasing. What wilderness is left is also mostly managed conservation areas. Meanwhile, about 3% of the surface is considered urban. I could not find a statistic for suburban, and there is currently no specific definition of what qualifies as suburban.

This, of course, is having an impact on animal life. One interesting question is how animals are adapting to these changes, and specifically are there species of animals that are adapting to urban life. Some species clearly do better than others in cities. Rats and pigeons are doing well. Peregrine falcons have also adapted well – the tall buildings give them excellent perching locations, and the pigeons provide an ample food source. Bats do well in Australian cities. In Africa some hyena populations are adapting to human food sources, and are believed to be in the process of self-domesticating.

Coyotes have also set up populations in many cities, feeding on the small animals that also live in cities. A significant part of the diet of urban coyotes is small rodents, including rats. Coyotes are well established in NYC, probably partly due to the abundant rodent population.

Racoons are another mammal that has adapted well to urban life. They tend to follow humans as a convenient food source. This has created a bit of an arms race between humans trying to keep racoons out of their garbage bins and racoons trying to find a way in. Racoons are smart critters to begin with. They have a relatively high neuronal density and good problem-solving skills. In one study city racoons displayed greater problem solving than their rural cousins.

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Last week I wrote about the de-extinction of the dire wolf by a company, Colossal Biosciences. What they did was pretty amazing – sequence ancient dire wolf DNA and use that as a template to make 20 changes to 14 genes in the gray wolf genome via CRISPR. They focused on the genetic changes they thought would have the biggest morphological effect, so that the resulting pups would look as much as possible like the dire wolves of old.

This achievement, however, is somewhat tainted by overhyping what was actually achieved, by the company and many media outlets. Although the pushback began immediately, and there is plenty of reporting about the fact that these are not exactly dire wolves (as I pointed out myself). I do think we should not fall into the pattern of focusing on the controversy and the negative and missing the fact that this is a genuinely amazing scientific accomplishment. It is easy to become blase about such things. Sometimes it’s hard to know in reporting what the optimal balance is between the positive and the negative, and as skeptics we definitely can tend toward the negative.

I feel the same way, for example, about artificial intelligence. Some of my skeptical colleagues have taken the approach that AI is mostly hype, and focusing on what the recent crop of AI apps are not (they are not sentient, they are not AGI), rather than what they are. In both cases I think it’s important to remember that science and pseudoscience are a continuum, and just because something is being overhyped does not mean it gets tossed in the pseudoscience bucket. That is just another form of bias. Sometimes that amounts to substituting cynicism for more nuanced skepticism.

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The evolution of the human brain is a fascinating subject. The brain is arguably the most complex structure in the known (to us) universe, and is the feature that makes humanity unique and has allowed us to dominate (for good or ill) the fate of this planet. But of course we are but a twig on a vast evolutionary tree, replete with complex brains. From a human-centric perspective, the closer groups are to humans evolutionarily, the more complex their brains (generally speaking). Apes are the most “encephalized” among primates, as are the primates among mammals, and the mammals among vertebrates. This makes evolutionary sense – that the biggest and most complex brains would evolve from the group with the biggest and most complex brains.

But this evolutionary perspective can be tricky. We can’t confuse looking back through evolutionary time with looking across the landscape of extant species. Any species alive today has just as much evolutionary history behind them as humans. Their brains did not stop evolving once their branch split off from the one that lead to humans. There are therefore some groups which have complex brains because they are evolutionarily close to humans, and their brains have a lot of homology with humans. But there are also other groups that have complex brains because they evolved them completely independently, after their group split from ours. Cetaceans such as whales and dolphins come to mind. They have big brains, but their brains are organized somewhat differently from primates.

Another group that is often considered to be highly intelligent, independent from primates, is birds. Birds are still vertebrates, and in fact they are amniotes, the group that contains reptiles, birds, and mammals. It is still an open question as to exactly how much of the human brain architecture was present at the last common ancestor of all amniotes (and is therefore homologous) and how much evolved later independently. To explore this question we need to look at not only the anatomy of brains and the networks within them, but brain cell types and their genetic origins. For example, even structures that currently look very different can retain evidence of common ancestry if they are built with the same genes. Or – structures that look similar may be built with different genes, and are therefore evolutionarily independent, or analogous.

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Humans identify and call each other by specific names. So far this advanced cognitive behavior has only been identified in a few other species, dolphins, elephants, and some parrots. Interestingly, it has never been documented in our closest relatives, non-human primates – that is, until now. A recent study finds that marmoset monkeys have unique calls, “phee-calls”, that they use to identify specific individual members of their group. The study also found that within a group of marmosets, all members use the same name to refer to the same individual, so they are learning the names from each other. Also interesting, different families of marmosets use different kinds of sounds in their names, as if each family has their own dialect.

In these behaviors we can see the roots of language and culture. It is not surprising that we see these roots in our close relatives. It is perhaps more surprising that we don’t see it more in the very closest relatives, like chimps and gorillas. What this implies is that these sorts of high-level behaviors, learning names for specific individuals in your group, is not merely a consequence of neurological develop. You need something else. There needs to be an evolutionary pressure.

That pressure is likely living in an environment and situation where families members are likely to be out of visual contact of each other. Part of this is the ability to communicate at long enough distance that will put individuals out of visual contact. For example, elephants can communicate over miles. Dolphins often swim in murky water with low visibility. Parrots and marmosets live in dense jungle. Of course, you need to have that evolutionary pressure and the neurological sophistication for the behavior – the potential and the need have to align.

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Surveys are always tricky because how you ask a question can have a dramatic impact on how people answer. But it is useful to ask the exact same question over a long period of time, because that can indicate how public attitudes are changing. This is one of the benefits of Gallup, which was founded in 1935 and is dedicated to high quality and representative polls. They have been asking the following question since 1982:

“Which of the following statements comes closest to your views on the origin and development of human beings — 1) Human beings have developed over millions of years from less advanced forms of life, but God guided this process, 2) Human beings have developed over millions of years from less advanced forms of life, but God had no part in this process, 3) God created human beings pretty much in their present form at one time within the last 10,000 years or so?”

It’s an imperfect way to ask these questions – the “less advanced life forms” is not really accurate, and the questions all assume or imply the existence of God. But by asking “which one comes closest” it does capture the essence of this issue. Option 3 is basically young-Earth creationism, option 2 is pure scientific evolution, and option 1 is everything else. From my view as a skeptic and science communicator, the results of this survey are dismal but also encouraging. At the start of the survey in 1982 the numbers were stark: 1 – 38%, 2 – 9%, and 3 – 44% (the rest undecided). Therefore 82% of Americans endorsed some form of creationism, and only 9% were willing to say that life resulted from evolution acting all by itself.

The most recent poll from this perspective is encouraging: 1 – 34%, 2 – 24%, and 3 – 37%. There is still a plurality endorsing young-Earth creationism, but those endorsing scientific evolution is up to 24%. These numbers also track with surveys on religion in the US. The young-Earth creationism figure is about the same as the number of Americans who identify as some kind of evangelical (something between 30 and 39%). Admittedly, this number can be squirrely depending on how you define “evangelical” and ask the question, but broadly defined, the numbers track. The scientific evolution numbers also track with those who answer on surveys that they are religiously unaffiliated, also now in the 20’s.

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Evolution deniers (I know there is a spectrum, but generally speaking) are terrible scientists and logicians. The obvious reason is because they are committing the primary mortal sin of pseudoscience – working backwards from a desired conclusion rather than following evidence and logic wherever it leads. They therefore clasp onto arguments that are fatally flawed because they feel they can use them to support their position. One could literally write a book using bad creationist arguments to demonstrate every type of poor reasoning and pseudoscience (I should know).

A classic example is an argument mainly promoted as part of so-called “intelligent design”, which is just evolution denial desperately seeking academic respectability (and failing). The argument goes that natural selection cannot increase information, only reduce it. It does not explain the origin of complex information. For example:

A big obstacle for evolutionary belief is this: What mechanism could possibly have added all the extra information required to transform a one-celled creature progressively into pelicans, palm trees, and people? Natural selection alone can’t do it—selection involves getting rid of information. A group of creatures might become more adapted to the cold, for example, by the elimination of those which don’t carry the genetic information to make thick fur. But that doesn’t explain the origin of the information to make thick fur.

I am an educator, so I can forgive asking a naive question. Asking it in a public forum in order to defend a specific position is more dodgy, but if it were done in good faith, that could still propel public understanding forward. But evolution deniers continue to ask the same questions over and over, even after they have been definitively answered by countless experts. That demonstrates bad faith. They know the answer. They cannot respond to the answer. So they pretend it doesn’t exist, or when confronted directly, respond with the equivalent of, “Hey, look over there.”

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In 1931 a fossil lizard was recovered from the Italian Alps, believed to be a 280 million year old specimen. The fossil was also rare in that it appeared to have some preserved soft tissue. It was given the species designation Tridentinosaurus antiquus and was thought to be part of the Protorosauria group.

A recent detailed analysis of the specimen, hoping to learn more about the soft tissue elements of the fossil, revealed something unexpected. The fossil is a fake (at least mostly). What appears to have happened is that a real fossil which was poorly preserved was “enhanced” to make it more valuable. There are real fossilized femur bones and some bony scales on what was the back of the lizard. But the overall specimen was poorly preserved and of not much value. What the forger did was carve out the outline of the lizard around the preserved bones and then paint it black to make it stand out, giving the appearance of carbonized soft tissue.

How did such a fake go undetected for 93 years? Many factors contributed to this delay. First, there were real bones in the specimen and it was taken from an actual fossil deposit. Initial evaluation did reveal some kind of lacquer on the specimen, but this was common practice at the time as a way of preserving the fossils, so did not raise any red flags. Also, characterization of the nature of the black material required UV photography and microscopic examination using technology not available at the time. This doesn’t mean they couldn’t have revealed it as a fake back then, but it is certainly much easier now.

It also helps to understand how fossils are typically handled. Fossils are treated as rare and precious items. They are typically examined with non-destructive techniques. It is also common for casts to be made and photographs taken, with the original fossils then catalogued and stored away for safety. Not every fossil has a detailed examination before being put away in a museum drawer. There simply aren’t the resources for that.

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Have you heard of Cope’s Rule or Foster’s Rule? American paleontologist Edward Drinker Cope first noticed a trend in the fossil record that certain animal lineages tend to get bigger over evolutionary time. Most famously this was noticed in the horse lineage, beginning with small dog-sized species and ending with the modern horse. Bristol Foster noticed a similar phenomenon specific to islands – populations that find their way to islands tend to either increase or decrease in size over time, depending on the availability of resources. This may also be called island dwarfism or gigantism (or insular dwarfism or gigantism).

When both of these things happen in the same place there can be some interesting results. On the island of Flores a human lineage, Homo floresiensis (the Hobbit species) experienced island dwarfism, while the local rats experienced island gigantism. The result were people living with rats the relative size of large dogs.

Based on these observations, two questions emerge. The first (and always important and not to be skipped) is – are these trends actually true or are the initial observations just quirks or hyperactive pattern recognition. For example, with horses, there are many horse lineages and not all of them got bigger over time. Is this just cherry-picking to notice the one lineage that survived today as modern horses? If some lineages are getting bigger and some are getting smaller, is this just random evolutionary change without necessarily any specific trend? I believe this question has been answered and the consensus is that these trends are real, although more complicated than first observed.

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