Unfortunately this article presents a sort of kindergarten version of evolution and is riddled with conceptual errors. There's no hierarchy in evolution so talking about "lower animals" is a mistake, as is the concept of "fittest" which Darwin never actually used. Darwin talked about being adapted to the environment (e.g. "a good fit") whereas the word "fittest" implies all manner of irrelevant ideas. Furthermore, as evolution operates by means of advantageous genes spreading across the gene pool, we need to consider population genetics - the fact that the larger and more distributed the population, the more difficult it is for any trait to spread across all members of that population. What happens with a species that is widely distributed is local speciation, which is what Darwin saw in the Galapagos finches he studied.
So the real question, unasked within this article, is simply: is speciation occurring within human populations? And if so, what sort of speciation may it be?
Once we ask the right question we can begin to think carefully about the factors involved. The most notable is that for the last 200 years, for the very first time in human history, mate selection has increasingly been determined not by proximity but by individual choice. Clever people are mating with other clever people while less intelligent people mate with other less intelligent people. We're even seeing phenotype changes: low IQ is associated today with obesity whereas intelligence is now highly correlated (in the West) with better physical health due to more adequate lifestyle choices. This alone, if continued over multiple generations, suggests powerful evolutionary drivers.
We can expect habitually obese lines of descent to evolve compensatory genetic mechanisms such as more resilient pancreatic insulin-producing cells that will be absent in higher-IQ lines of descent due to more intelligent people making better lifestyle choices and therefore not suffering from obesity-induced diseases, for example.
Other possible genetic variations are likely to develop in terms of metabolic pathways involved with neural function. Lines of descent resulting from clever people mating with other clever people and relying on intelligence for environmental success are likely to spur changes in how neurons utilize glucose, as well as a wide range of other phenotypical alterations favoring (perhaps) greater neural plasticity, a higher degree of dendritic connections, and other alterations that have the effect of enhancing cognitive function. These genetic changes will be largely absent in lines of descent deriving from less clever people mating with their less clever peers.
So it’s highly likely that, assuming we don’t accidentally destroy every vestige of modern civilization and return to much more primitive modes of existence, we’ll see increased speciation occurring over the next few hundred years. But it will be localized, with some common traits across different groups (assuming the modern Western-style way of life persists in some form or another around the globe) but with a reasonable probability of convergent evolution rather than simple inheritance-based evolution. By this I mean that there may be multiple different ways in which phenotype alterations can be effected, so while the outcome may be similar across two widely separated groups, the means by which that outcome is achieved may vary. We already know that a great many genes code for many proteins that occupy the same conformal phase-space and therefore nature often has multiple options by means of which creatures can adapt to changing circumstances.