African origins and the rise of carnivory
Trent W. wrote in with a short question that generated a long answer. Lots of other people have similar questions, so we decided to share both it and the answer:
I was wondering if the Out of Africa theory is false, especially due to the location (maybe it should be out of the Caucus Mountains as the Biblical theory), why is Africa so genetically diverse to not only non-Africans but, each other from what I hear? Secular scientists posit the diversity as the reason they are oldest population and the one from which everyone else came. Does diversity in a single location, or continent, entail that a population is older?
Dr Robert Carter responds:
This is an excellent question, and I know many others are asking similar ones, so I will do my best to answer it thoroughly.
First, given multiple evolutionary assumptions, most scientists have concluded that humans originated in Africa. The high levels of genetic diversity in Africa help to drive them in that direction. Yet, there are so many unknown factors in historical estimations like this. One needs to be very careful when approaching such questions, and I am afraid that the evolutionists have jumped the gun.
First, yes, Africa has more genetic diversity than the rest of the world put together. They also have some very ‘deep’ branches in the Y and mitochondrial family trees. Yet, the ‘deepest’ branches found to date are in the Neanderthal and Denisovan lineages, so clearly the fact that any ‘deep’ lineage hangs on in a population is a matter of chance. I put ‘deep’ in scare quotes because evolutionists assume the longest branches are the oldest branches. I do not assume the ‘molecular clock’ works and have good reason to question it.1 Thus, a ‘deep’ branch to me is simply one that has accumulated more mutations than its relatives. This is not hard to imagine, given the effects of Patriarchal Drive, mutations accumulating in DNA repair systems, and extreme levels of inbreeding that would occur as people broke up into small bands as they migrated away from Babel.
Why is Africa so different? There are multiple possible reasons.
a) The mutation rate could be different. We know that different versions of our DNA repair systems exist, so if one group got one version and another group got another version, we could see different letter changes in the respective groups. This is the weakest supporting argument. I chose to lead with it just to get it out of the way.
b) A sweep could have happened across Eurasia but not within Africa that replaced an older population with newer migrants. We see this in the genetic data as Neanderthals (an early post-Flood people group) were replaced across Eurasia (with limited interbreeding) with the early modern hunter gatherers, who were then replaced (with limited interbreeding) with the farmers who expanded from the Middle East. One known sweep did occur in Africa. It is called the Bantu Expansion.2 Starting as late as maybe 1500 years ago, Bantu-speaking people expanded eastward and southward from their home territory in central Africa. They pushed out or killed off most everybody in their path. Thus, the genetics of the few ancient individuals we have managed to find in SE Africa do not match the modern inhabitants.3 But the genetics does match the Khoi-San hunter gatherers who have managed to maintain a foothold in extreme SW Africa. This ‘sweep’ was late in history, however, so it was easier to detect. It was also incomplete and was restricted to just a portion of the continent.
c) Africa could have started off with more descendants of Noah. After all, the Bible tells us nothing about where the sub-Saharan Africans came from. We know they are descendants of the Ark passengers, but that’s all. People assume they came from “Ham” because a couple of his sons settled Africa. But Africa is a large continent and the Bible only talks about a small portion (Put and Egypt) in the NE. Also, there is a decided lack of sub-Saharan genes in the Egyptian population until after the rise of Islam,4 so equating “Ham” with the peoples of southern Africa could be very wrong.
d) The recombination rate could be higher among Africans.5 High recombination rates constantly scramble the genome and act to prevent the loss of ancestral blocks of DNA over time. But recombination is controlled by an enzyme called PRDM9. Africans have more PRDM9 sites than non-Africans, thus it is expected they would have higher recombination rates. Several evolutionists have questioned me about these claims recently, claiming that PRDM9 is not as clear a case as I assumed. This may or may not be true, but the possibility of differential recombination rates is still an open question.
e) The African population could have been broken up into multiple isolated tribes for much of its existence.6 This would enhance genetic differences among them. When those small populations eventually grew and started sharing genes, the result would be a very diverse population.
f) Multiple groups could have migrated into Africa over the millenia (3). There is evidence for ‘back migration’ into Africa. Even the most important Y chromosome scientists (i.e. Poznic, whose work serves as the 1000 Genomes Project Y chromosome data) are now saying that it is “more parsimonious” (see ref 1) that the group that represents 95% of Africans (e.g. E1b1a, see figure 1 here) originated outside Africa. This is due to the fact that this group splits off non-Africans in the Y chromosome tree.
If you are a real glutton for punishment, see my Journal of Creation article The Neutral Model of evolution and recent African origins.
In the end, it is only assumption that drives many scientists to conclude Africa is the source population, and therefore the oldest population, of all modern people. Yet, when the contradictions to these assumptions are laid out like this, we can see that it is just a story. There is no reason to reject biblical history based on the speculations of even the majority of scientists. They assume too much.
Andrew S (Australia) wrote in:
I don’t know whether you are aware of the public interest in peregrine falcons nesting near the top of a ‘skyscraper’ in Melbourne. In case you are not, here is the website [link deleted as per feedback rules].
I assure you that I have searched the Creation website for an answer to the two questions to follow. The only article I found that seemed approximately pertinent is The carnivorous nature and suffering of animals by Robert J.M. Gurney. His endorsement of Alec Motyer’s work in Isaiah was helpful, but, to come to the peregrine falcon, what should a Bible-believing Christian, who rejects the approach of ‘theistic evolutionists’, make of the fact that the peregrine falcon is so wondrously designed to capture and kill?
If these birds are among those referred to in Genesis1:29-30 and therefore took their food from green plants at first, are we to assume that they were designed in anticipation of the curse that would come after the Fall? Alternatively, are there any grounds for thinking that they might have been created after the Fall? Any help you can give me, would be much appreciated.
Dr Robert Carter Responds:
You ask a very interesting set of questions about the origin of carnivory and the apparent design for hunting among animals. We have addressed these concerns multiple times in different ways, for example, see Skeptics challenge: a ‘God of love’ created a killer jellyfish? Yet, perhaps it is time for a refresher. There are at least three possible explanations. The classic view is that God ‘foreknew’ the Fall and therefore put into His creations exactly what they would need when the Fall came. And, since there is no reason to suspect that Adam and Eve waited a long time (specifically because they had been commanded to procreate but Eve was not yet pregnant), a falcon-like progenitor would not have gone hungry. This is not my favourite response, but one does find it in many theological works.
Second, given a state where all animals were designed to eat plants, mutation and selection may have caused changes to the original design. I am also not a huge fan of this position because it sounds too Darwinian. But we cannot rule out all such possibilities. Male mosquitoes, for example, feed on flower nectar. Thus, I can easily imagine that mosquitoes were not originally made for sucking blood. It would take only one small change in the female’s antennae to accidentally hone in on, say, carbon dioxide instead of methylene, and that pointy proboscis that was once used to suck nectar would come in quite handy, and that blood meal would allow her to create many more times the number of eggs as her nectar-sucking sisters. This is all rather speculative, especially since there are other features of mosquitoes that aid them in their bloody quest for food, but I cannot completely rule out natural selection in all cases.
The third option is called exaptation. This is similar to adaptation, where a tool is changed to suit a new purpose. But in exaptation the tool is simply repurposed for a new use. I can use a screwdriver as a hammer, and it would work in many cases, even though this was not what it was originally designed to do. It might not be a very good hammer in most cases, but this does not mean it cannot be done. The claws of black bears are great for digging up roots. The teeth are wonderfully designed to strip berries off a stem without removing the leaves. But those same teeth and claws are very good at killing and eating seals. Based on the isotopic composition of the teeth and bones, the largest bear ever discovered, an extinct cave bear found in Europe, was clearly an herbivore. Polar bears seem to derive from ancient cave bears, with links to extinct bears from Ireland.7 Thus, exaptation was clearly at work in the rise of polar bears.
Let us also not forget that there are herbivorous examples among animal groups we think of as ‘carnivores’: a newly-discovered mango-eating monitor lizards in the Philippines,8 seagrass eating sharks (bonnethead sharks get a significant portion of the their dietary needs met this way), palm nut vultures (which get a significant portion of the diet from palm nuts of several species), etc.
Thus, to explain the apparent ‘hunting’ design in falcons and other birds of prey, all we have to do is imagine that God created birds with sharp beaks and strong claws that loved to soar and dive. This included birds from several disparate groups (i.e. falcons are more similar to parrots than to eagles). After the Fall, a mixture of forethought, adaptation, and exaptation led to the rise of the conspicuously-good-at-hunting birds of prey.
For more information, see:
- The Genesis Account (Dr Sarfati discusses the rise of carnivory in detail)
- The Genesis Academy (I discuss exaptation and adaptation in one specific episode)
- and our Death and Suffering Q&A
References and notes
- Carter, R.W., Lee, S.S., and Sanford, J.C., An overview of the independent histories of the human Y-chromosome and the human mitochondrial chromosome. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 133–151. Pittsburgh, Pennsylvania: Creation Science Fellowship, 2018. Return to text.
- Tishkoff, S.A. et al., The genetic structure and history of Africans and African Americans, Science 324(5930):1035–1044, 2009. Return to text.
- Skoglund, P. et al., Reconstructing prehistoric African population structure, Cell 171:59–71, 2017. Return to text.
- Schuenemann, V.J. et al., Ancient Egyptian mummy genomes suggest an increase of Sub-Saharan African ancestry in post-Roman periods, Nat. Comm. 8:15694, 2017. Return to text.
- Hinch, A.G. et al., The landscape of recombination in African Americans, Nature 476:170–177, 2011. Return to text.
- Behar, D.M. et al., and The Genographic Consortium, The dawn of human matrilineal diversity, American Journal of Human Genetics 82:1130–1140, 2008. Return to text.
- Edwards, C.J. et al. Ancient hybridization and an Irish origin for the modern polar bear matriline, Current Biology 21:1251–1258, 2011. Return to text.
- Geddes, L., Meet the giant fruit-eating monitor lizard, newscientist.com/article/dn18741-meet-the-giant-fruit-eating-monitor-lizard, 7 April 2010. Return to text.