Thread: A fish is not a fish: Aquatic food may have had implications for hominin evolution

Journal of Human Evolution (impact factor: 4.09). 01/2014; doi: 10.1016/j.jhevol.2014.04.004
Abstract: From c. 2 ma (millions of years ago) onwards, hominin brain size and cognition increased in an unprecedented fashion. The exploitation of high-quality food resources, notably from aquatic ecosystems, may have been a facilitator or driver of this phenomenon. The aim of this study is to contribute to the ongoing debate on the possible role of aquatic resources in hominin evolution by providing a more detailed nutritional context. So far, the debate has focused on the relative importance of terrestrial versus aquatic resources while no distinction has been made between different types of aquatic resources. Here we show that Indian Ocean reef fish and Eastern African lake fish yield on average similarly high amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA). Hence a shift from exploiting tropical marine to freshwater ecosystems (or vice versa) would entail no material difference in dietary long-chain polyunsaturated fatty acid (LC-PUFA) availability. However, a shift to marine ecosystems would likely mean a major increase in access to brain-selective micronutrients such as iodine. Fatty fish from marine temperate/cold waters yield twice as much DHA and four times as much EPA as tropical fish, demonstrating that a latitudinal shift in exploitation of african coastal ecosystems could constitute a significant difference in LC-PUFA availability with possible implications for brain development and functioning. We conclude that exploitation of aquatic food resources could have facilitated the initial moderate hominin brain increase as observed in fossils dated to c. 2 ma, but not the exceptional brain increase in later stages of hominin evolution. We propose that the significant expansion in hominin brain size and cognition later on may have been aided by strong directional selecting forces such as runaway sexual selection of intelligence, and nutritionally supported by exploitation of high-quality food resources in stable and productive aquatic ecosystems.

Finally!!!

I cant say much until I am able to read the full paper, but the abstract makes it clear that its not in anyway a paper asserting that a fish diet was certain, only that it ma have contributed, if cold water fish were eaten. Have you read the full article and if so can you send a copy?

Originally Posted by Paleoichneum

I cant say much until I am able to read the full paper, but the abstract makes it clear that its not in anyway a paper asserting that a fish diet was certain, only that it ma have contributed, if cold water fish were eaten. Have you read the full article and if so can you send a copy?

I downloaded the article in PDF format via my faculty account and uploaded it to my Google Drive account. You can read it here:
Joordens, J.C.A., et al. (2014), "A fish is not a fish (...)", Journal of Human Evolution, DOI: 10.1016/j.jhevol.2014.04.004

Thanks CES it read it through when I get home tonight

Paleo, as you read it, try to note, what comma sentence you're constantly looking for, that would allow you to reject the entire possibility of seafood having fueled the growth of our brain.

Originally Posted by cengelbrecht

paleo, as you read it, try to note, what comma sentence you're constantly looking for, that would allow you to reject the entire possibility of seafood having fueled the growth of our brain.

huh?

considerable brain expansion has occurred in cetaceans (particularly in Delphinidae), but it took place millions of years after adaptation to a completely aquatic lifestyle and could not be causally connected to an aquatic lifestyle (Marino, 2007; Xu et al., 2012). In extant herpestids, mustelids and procyonids, the species that eat aquatic prey have the largest absolute brain sizes of their families (Shabel, 2010), but these increases in brain size do not reflect an explosive brain expansion and increase in cognition such as is seen in the human lineage (e.g., Roth and Dicke, 2005). This suggests that while aquatic resource exploitation by hominins may have triggered and/or contributed to initial moderate brain growth, one or more additional factors are required to explain the extreme events in brain growth and cognition in the hominin lineage.

This is from the conclusions/ discussion section of the article. The authors note that the omega fatty acids are important, but likely not the primary cause of the volume increase.

Also of note is that wild caught Kangaroo and Brushtail both have higher levels of OFA then seafoods do, as a result of their diet of deep green leafy vegetation.

Originally Posted by Paleoichneum

considerable brain expansion has occurred in cetaceans (particularly in Delphinidae), but it took place millions of years after adaptation to a completely aquatic lifestyle and could not be causally connected to an aquatic lifestyle (Marino, 2007; Xu et al., 2012). In extant herpestids, mustelids and procyonids, the species that eat aquatic prey have the largest absolute brain sizes of their families (Shabel, 2010), but these increases in brain size do not reflect an explosive brain expansion and increase in cognition such as is seen in the human lineage (e.g., Roth and Dicke, 2005). This suggests that while aquatic resource exploitation by hominins may have triggered and/or contributed to initial moderate brain growth, one or more additional factors are required to explain the extreme events in brain growth and cognition in the hominin lineage.

This is from the conclusions/ discussion section of the article. The authors note that the omega fatty acids are important, but likely not the primary cause of the volume increase.

Also of note is that wild caught Kangaroo and Brushtail both have higher levels of OFA then seafoods do, as a result of their diet of deep green leafy vegetation.

Since my knowledge about this topic is next to nothing, would you be willing to explain what this paper is about in layman's terms?
As such, more people could partake in this thread.

Originally Posted by Cogito Ergo Sum

Since my knowledge about this topic is second to none, would you be willing to explain what this paper is about in layman's terms?
As such, more people could partake in this thread.

A little diversion for a lesson in English, which I know is not your first language. "Second to none" would mean your knowledge is as good or better than anyone else's - it is in first place. I think you may have meant perhaps "next to nothing" (since you are asking for an explanation).

Originally Posted by Paleoichneum

Also of note is that wild caught Kangaroo and Brushtail both have higher levels of OFA then seafoods do, as a result of their diet of deep green leafy vegetation.

Which are in Australia, not the cradle of humanity in East Africa.

Originally Posted by Cogito Ergo Sum

Since my knowledge about this topic is next to nothing, would you be willing to explain what this paper is about in layman's terms?
As such, more people could partake in this thread.

It means that this topic finally stands to be vindicated. For a couple of decades now, it has been argued, that our big brain likely couldn't have evolved to its current size without our hominin ancestors consistently feeding off a seafood proteine diet, at least partially. These food groups contain the exact set of brain-selective nutrients, specific fatty acids and especially iodine, that still today optimizes our brain's development and upkeep.

To quote the paper:

A key question in paleoanthropology is therefore: what drove the striking brain growth in the hominin lineage over time, and how was it ‘paid for’ in nutritional terms? In this paper we aim to address the second part of the question, and will discuss the implications of our findings for the first part of the question.

Josephine Joorden et al's paper focuses much on fish, or though shellfish in my opinion is a much more likely source to the nutrients in question. This is what archeological finds of shell middens show, that specimens of the Homo genus had access to all through the stone age, from at least 300,000 years ago till today. But baby steps.

CES. I will reread he paper and post a summation tonigt.

Engle. While it is correct that they are gondwanan, they are also a data point that shows the assertion of fish being the only option for high OFA content to be incorrect, and that landammals on a diet of deep leafy greens also can produce high levels, which would have been quite.possible in the late Miocene with the floral tropical/temperate forest composition.

Originally Posted by Paleoichneum

Originally Posted by Paleoichneum

Also of note is that wild caught Kangaroo and Brushtail both have higher levels of OFA then seafoods do, as a result of their diet of deep green leafy vegetation.

Which are in Australia, not the cradle of humanity in East Africa.

Engel. While it is correct that they are gondwanan, they are also a data point that shows the assertion of fish being the only option for high OFA content to be incorrect, and that land mammals on a diet of deep leafy greens also can produce high levels, which would have been quite possible in the late Miocene with the floral tropical/temperate forest composition.

Then why don't kangaroos and brushtails have big brains, then?

Originally Posted by CEngelbrecht

Then why don't kangaroos and brushtails have big brains, then?

Given that this type of assertion has been discussed in previous AAH threads, I am going to wait for you to acknowledge that evolution and biology do not function this way, and the above statement is a red herring and not an actual discussion of the information.

Originally Posted by CEngelbrecht

Originally Posted by Cogito Ergo Sum

Since my knowledge about this topic is next to nothing, would you be willing to explain what this paper is about in layman's terms?
As such, more people could partake in this thread.

It means that this topic finally stands to be vindicated. For a couple of decades now, it has been argued, that our big brain likely couldn't have evolved to its current size without our hominin ancestors consistently feeding off a seafood proteine diet, at least partially. These food groups contain the exact set of brain-selective nutrients, specific fatty acids and especially iodine, that still today optimizes our brain's development and upkeep.

To quote the paper:

A key question in paleoanthropology is therefore: what drove the striking brain growth in the hominin lineage over time, and how was it ‘paid for’ in nutritional terms? In this paper we aim to address the second part of the question, and will discuss the implications of our findings for the first part of the question.

Josephine Joorden et al's paper focuses much on fish, or though shellfish in my opinion is a much more likely source to the nutrients in question. This is what archeological finds of shell middens show, that specimens of the Homo genus had access to all through the stone age, from at least 300,000 years ago till today. But baby steps.

As I said, i will give a summation of the article this evening, but I object to the assertion of any sort of "vindication" being derived from this article, as it is clear, from the abstract and conclusion paragraphs that have been posted, that the authors do not make any statements with that level of certainty.

Originally Posted by Paleoichneum

Originally Posted by cengelbrecht

paleo, as you read it, try to note, what comma sentence you're constantly looking for, that would allow you to reject the entire possibility of seafood having fueled the growth of our brain.

huh?

Yeah, I know, exactly.

Originally Posted by CEngelbrecht

Originally Posted by Paleoichneum

Originally Posted by cengelbrecht

paleo, as you read it, try to note, what comma sentence you're constantly looking for, that would allow you to reject the entire possibility of seafood having fueled the growth of our brain.

huh?

Yeah, I know, exactly.

That was me indicating i dont know what you are trying to say. Though it sounds vaguely like a personal jab. your reply has not at all clarified your first post

Originally Posted by Paleoichneum

Though it sounds vaguely like a personal jab. your reply has not at all clarified your first post

You know what, right now I'm conflicted between wanting to gloat like a bastard, and just go "Right, finally they're waking up, what ever, let's just try to get it straight from now on." On the last part it's really depressing to witness, that it has to take half a century for a reasonable scientific notion to even be treated as reasonable, just because of some silly sociological nonsense. I guess I'm still expecting way too much of human nature, even among trained scholars.

Anyways ...

Originally Posted by CEngelbrecht

You know what, right now I'm conflicted between wanting to gloat like a bastard, and just go "Right, finally they're waking up, what ever, let's just try to get it straight from now on." On the last part it's really depressing to witness, that it has to take half a century for a reasonable scientific notion to even be treated as reasonable, just because of some silly sociological nonsense. I guess I'm still expecting way too much of human nature, even among trained scholars.

Anyways ...

You don't really have anything to gloat about. The study in no way validates your belief that our ancestors were aquatic apes. Did they catch fish in the shallow waterways around them? Probably.

But the study clearly states that it was not the sole cause of the increase in brain size in our early ancestors. And it proposes that came about through sexual selection, more importantly, intelligent sexual selection and what they call aquatic resource exploitation was not the driving force. They also discuss shallow water exploitation. Which again points to a terrestrial existence instead of an aquatic existence.

And you should also read page 7 of the study, where they discuss the role of fat in brain development and sexual selection (page 8).

They propose that human fat deposits are crucial buffers that ensure provision of fuel to feed the hungry brain, and their findings support the notion that a concomitant increase in brain size and fat storage could only be facilitated in an environment, such as shallow-water aquatic ecosystems, providing a stable and abundant supply of resources rich in energy and LC-PUFA (such as EPA and DHA) that constitute limiting factors for neurodevelopment and functioning. In fact, LC-PUFA might also have played an important role in the development of human adipose tissue. For example, while the brain contains the highest concentrations of DHA, it contains only 23% of total DHA stored in the human body. The human adipose tissue in contrast, consisting mainly of saturated and monounsaturated fatty acids for energy generation, contains 50% of the total DHA stored in the human body (Kuipers et al., 2012b, c). This DHA storage is most critical in infants when the brain is developing. Cunnane et al. (2000) have shown that adipose tissue stores at birth have enough DHA to meet the growing brain's DHA requirement for about three months.

As in selection for increasing brain size, sexual selection may also have been relevant when considering the development of fat deposits (buttocks, thighs, breasts) on the human body, influencing the waist-hip ratio and hence the attractiveness to mates (e.g., Lassek and Gaulin, 2008). Sexual selection of intelligence is not contradictory to sexual selection of fat but, instead, mutually enforcing: the typically preferred low waist-hip ratio indicates presence of critical resources for brain development. Hence, the review of Lassek and Gaulin (2008) suggests that there is a functional link between two highly derived human traits, namely a very large brain and sexually dimorphic fat distributions.

We concede that at present, finding the definite explanation for the explosive hominin brain increase remains a matter of more research, and many factors may be involved (e.g., the cooking of food; Wrangham and Carmody, 2010). We conclude that exploita-
tion of aquatic food resources could have facilitated initial moderate hominin brain increase as first observed in fossils dated to c.2 Ma, and could have nutritionally contributed to the extreme brain increase (and fat storage) later on. However, it appears to be un-
likely that aquatic resource exploitation was the sole driver for the extreme brain growth and development in the later members of the human lineage.