If these first colonizers were indeed Homo erectus, then it seems that they rapidly evolved a small stature within 300,000 years of their arrival – a shorter time span than was previously thought.
Our combined analyses of gene repertoire and recombination in Campylobacter indicate that despite the fact these two species share the same habitat, they have both evolved a small number of unique core genes and developed a species recombination barrier.
Burt [ 49] in a "fission-fusion" hypothesis suggested that most microchromosomes were already present in the common dinosaur ancestor that gave rise to birds (which probably had already evolved a small genome size and karyotype of around 2 n = 60 including 20 pairs of microchromosomes) but that chromosome fission created the remainder, presumably including the smallest ones.
They acquired no diseased deformities, nor did they evolve a smaller stature over time.
For example, Aiello and her colleagues proposed that when our brains began to expand dramatically about 1.6 million years ago, our direct ancestor Homo erectus evolved a smaller gut that sucked up less energy (Science, 15 June 2007, p. 1560).
That's the analogy Arne Hendriks, the conceptual artist behind the Incredible Shrinking Man, used when proposing that in the right environmental conditions, humans could shrink, or rather, they could evolve a smaller form.
In fact, this is almost exactly what biologists think has occurred with two species of Galapagos finch, Geospiza fuliginosa, which has evolved a smaller beak and body size, and Geospiza fortis, which has evolved the larger beak and body (Schluter et al. 1985).
On the other hand, the green alga C. reinhartdii and lower land plants P. patens and S. moellendorffii apparently evolved a smaller set of MKKs relative to the flowering plants, which indicates an expansion of MKK gene family after the divergence of flowering plants from the other lineages.
Under a Darwinian model of speciation, one would expect to find that some H. habilis would continue evolving after a small subpopulation had branched off to later become H. erectus.
Two major CO2 peaks centred at 210 and 330 °C markedly decreased as increasing the treatment temperature to evolve a relative small amount of CO2 at temperatures above the maximum calcination temperature (i.e., 350 °C), Fig. 7a.
