Skip to main content
SpringerLink
Log in

The Cambrian Explosion and the Origins of Embodied Cognition

  • Long Article
  • Published:
Biological Theory Aims and scope Submit manuscript

Abstract

Around 540 million years ago there was a sudden, dramatic adaptive radiation known as the Cambrian Explosion. This event marked the origin of almost all of the phyla (major lineages characterized by fundamental body plans) of animals that would ever live on Earth, as well as the appearance of many notable features such as rigid skeletons and other hard parts, complex jointed appendages, eyes, and brains. This radical evolutionary event has been a major puzzle for evolutionary biologists since Darwin, and while our understanding of it has recently improved with new fossil finds, richer molecular phylogenies, and better grasp of ecological, evolutionary, and developmental processes generally, unanswered questions remain. In this article I argue that a basic cognitive toolkit for embodied, object-oriented, spatial cognition—what I call Basic Cognitive Embodiment—is a practical necessity for control of a large, mobile, complexly articulated body in space. This hypothesis allows us to relate the complexification of animal bodies to the complexification of perception, cognition, and behavior in a way that can help to fill in gaps in our emerging picture of the Cambrian Explosion, as well as shed light on the deep evolutionary origins of the mind.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Notes

  1. A crown group is the set of all descendants (living and dead) of the last common ancestor of the living representatives of a group. A stem group is a lineage that split off from the lineage leading to the crown group before the last common ancestor. So, for example, the extinct Carolina parakeet is a crown bird species, since it is more closely related to other parakeets then the latter are to, say, penguins. Archaeopteryx is probably a stem bird; if that is true, then all living birds are more closely related to each other than to Archaeopteryx. A cogent and influential discussion of these important concepts is found in Budd and Jensen (2000).

  2. Ediacarian fauna was not recognized until the mid 1900s (Narbonne 2005).

  3. As an extreme example, Blair and Hedges (2005) argue, based on molecular evidence, that the deuterostome lineage originated 900 mya, and that jawed vertebrates had already split from agnathans (the group that includes lampreys and hagfish) some 652 mya, deep in the pre-Cambrian. Such early divergence estimates as well as the methods used to infer them are, however, highly controversial.

  4. Phyla are major monophyletic lineages corresponding more or less to the fundamental bauplans. The exceptions are groups characterized by a common bauplan that are probably paraphyletic, such as porifera, which probably encompasses bilateria, and rotifera, which encompasses acanthocephalan (Collins and Valentine 2001).

  5. Incredibly, some phyla are represented today by only one or a few species and are extremely simple. Perhaps these remarkable animals have remained largely unchanged since the Cambrian. Examples include Placozoa, Micrognathozoa, Xenoturbella, Cycliophora, and Phoronida.

  6. One extinct group of animals, the nectocarids, represent a fascinating possible fourth origin of CABs. Though some authors place nectocarids within cephalopoda, this is unlikely for many reasons, and Nectocaris pteryx may well be the sole described species from an ancient and otherwise unknown phylum of complex animals (Kroger et al. 2011; Mazurek and Zaton 2011).

  7. This interpretation has not been without its own controversies. Fortey (2001), for example, argued that the apparent “explosive” radiation of form is an artifact of the fossil record. However, a majority that approaches consensus now exists that the Cambrian Explosion was a real phenomenon.

  8. Cnidarians were probably predators much earlier, as evidenced by the commonality of the cnidocyte (the stinging cell used to kill prey) to all crown cnidaria, which diverged around 680 mya (Erwin et al. 2011).

  9. Parker’s views on arthropod phylogeny are rather heterodox. He claims that all crown arthropods, as well as extinct groups such as anomalocaris and opabinia, are derived from trilobites (Parker 2004, p. 217). This is contrary to most recent reconstructions, which consider trilobites to be crown arthropods (Rota-Stabelli et al. 2011), and consider anomalacaris, opabinia, and other Cambrian “oddballs” with well-developed eyes to be stem arthropods (Budd and Telford 2009; Giribet and Edgecombe 2012; Paterson et al. 2011). This does not undermine the basic thrust of his argument for the importance of arthropod eyes in driving the CE, although it does problematize aspects of the narrative he articulates (Parker 2004).

  10. Parker is dismissive of the importance of brain evolution in the Cambrian Explosion: “For an eye to work, sizeable brain and nerve cables are required, and these were in part borrowed from other senses. This is the most conceivable way in which an eye can suddenly achieve vision, after its leap from simple progenitors, the light perceivers. What does this borrowing tell us? It indicates that at least some senses had evolved to a reasonable degree of sophistication before the Cambrian, so that they had established a nerve network including brain space. In turn this means they could not have triggered the Cambrian explosion” (Parker 2004, p. 285).

  11. See Merker (2005) for a discussion of similar considerations of control of complex, active bodies, albeit one with a different focus and very different explanatory aims.

  12. See Waloszek et al. (2007) for a fascinating review of the early diversification of arthropod head structures, most of which apparently functioned in food handling of one sort or another. The authors claim that this was an important driver of arthropod evolution, in line with my hypothesis.

  13. Although of course a genetic toolkit for brain development is a prerequisite for having a brain. But remember that many lineages share the basic toolkit of developmental gene-regulatory networks without evolving CABs.

References

  • Avital E, Jablonka E (2000) Animal traditions: behavioural inheritance in evolution. Cambridge University Press, Cambridge

  • Baldwin JM (1896) A new factor in evolution. Am Nat 30(441–451):536–553

    Article  Google Scholar 

  • Bateson P (2005) The return of the whole organism. J Biosci 30:31–39

    Article  Google Scholar 

  • Blair JE, Blair Hedges S (2005) Molecular phylogeny and divergence times of deuterostome animals. Mol Biol Evol 22:2275–2284

    Article  Google Scholar 

  • Braitenberg V (1986) Vehicles: experiments in synthetic psychology. MIT Press, Cambridge

    Google Scholar 

  • Budd GE, Jensen S (2000) A critical reappraisal of the fossil record of the bilaterian phyla. Biol Rev 75(2):253–295

    Article  Google Scholar 

  • Budd GE, Telford MJ (2009) The origin and evolution of arthropods. Nature 457:812–817

    Article  Google Scholar 

  • Butterfield NJ (1997) Plankton ecology and the Proterozoic-Phanerozoic transition. Paleobiology 23:247–262

    Google Scholar 

  • Collins A, Valentine J (2001) Defining phyla: evolutionary pathways to metazoan body plans. Evol Dev 3:432–442

    Article  Google Scholar 

  • Conway Morris S (2000) The Cambrian explosion: slow-fuse or megatonnage? Proc Natl Acad Sci 97:4426–4429

    Article  Google Scholar 

  • Darwin CR (1859) On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life, 1st edn. John Murray, London

    Google Scholar 

  • Erwin DH, Laflamme M, Tweedt SM, Sperling EA, Pisani D, Peterson KJ (2011) The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334:1091–1097

    Article  Google Scholar 

  • Fike DA, Grotzinger JP, Pratt LM, Summons RE (2006) Oxidation of the Ediacaran ocean. Nature 444:744–747

    Article  Google Scholar 

  • Fortey R (2001) The Cambrian explosion exploded? Science 293:438–439

    Article  Google Scholar 

  • Friedman M (2010) Explosive morphological diversification of spiny-finned teleost fishes in the aftermath of the end-Cretaceous extinction. Proc R Soc Lond B 277:1675–1683

    Article  Google Scholar 

  • Ginsburg S, Jablonka E (2010) The evolution of associative learning: a factor in the Cambrian explosion. J Theor Biol 266(1):11–20

    Google Scholar 

  • Giribet G, Edgecombe GD (2012) Reevaluating the arthropod tree of life. Annu Rev Entomol 57:167–186

    Article  Google Scholar 

  • Hardy A (1965) The living stream: a restatement of evolution theory and its relation to the spirit of man. Collins, London

    Google Scholar 

  • Kirschvink JL (1992) Late Proterozoic low-latitude global glaciation: the snowball Earth. In: Schopf JW, Klein C (eds) The Proterozoic biosphere: a multidisciplinary study. Cambridge University Press, Cambridge, pp 51–58

    Google Scholar 

  • Kroger B, Vinther J, Fuchs D (2011) Cephalopod origin and evolution: a congruent picture emerging from fossils, development and molecules. BioEssays 33:602–613

    Article  Google Scholar 

  • Marshall CR (2006) Explaining the Cambrian “explosion” of animals. Annu Rev Earth Planet Sci 34:355–384

    Google Scholar 

  • Mazurek D, Zaton M (2011) Is Nectocaris pteryx a cephalopod? Lethaia 44:2–4

    Article  Google Scholar 

  • Merker B (2005) The liabilities of mobility: a selection pressure for the transition to consciousness in animal evolution. Conscious Cogn 14:89–114

    Article  Google Scholar 

  • Narbonne GM (2005) THE EDIACARA BIOTA: Neoproterozoic origin. Annu Rev Earth Planet Sci 33:421–442

    Article  Google Scholar 

  • Niklas KJ (1994) Morphological evolution through complex domains of fitness. Proc Natl Acad Sci USA 91:6772–6779

    Article  Google Scholar 

  • Niklas KJ (1997) Effects of hypothetical developmental barriers and abrupt environmental changes on adaptive walks in a computer generated domain for early vascular land plants. Paleobiology 23:63–76

    Google Scholar 

  • Niklas KJ (2004) Computer models of early land plant evolution. Annu Rev Earth Planet Sci 32:47–66

    Article  Google Scholar 

  • Northcutt RG (2012) Evolution of centralized nervous systems: two schools of evolutionary thought. Proc Natl Acad Sci USA 109(Suppl. 1):10626–10633

    Article  Google Scholar 

  • Oliver KR, Greene WK (2009) Transposable elements: powerful facilitators of evolution. BioEssays 31:703–714

    Article  Google Scholar 

  • Parker A (2004) In the blink of an eye: how vision sparked the big bang of evolution. Basic Books

  • Paterson JR et al (2011) Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature 480:237–240

    Article  Google Scholar 

  • Peterson KJ et al (2008) The Ediacaran emergence of bilaterians: congruence between the genetic and the geological fossil records. Philos Trans R Soc Lond B 363:1435–1443

    Article  Google Scholar 

  • Ritchie MG (2007) Sexual selection and speciation. Annu Rev Ecol Evol Syst 38:79–102

    Article  Google Scholar 

  • Rota-Stabelli O, Campbell L, Brinkmann H, Edgecombe GD, Longhorn SJ, Peterson KJ, Pisani D, Philippe H, Telford MJ (2011) A congruent solution to arthropod phylogeny: phylogenomics, microRNAs and morphology support monophyletic Mandibulata. Proc R Soc B 278(1703):298–306

    Article  Google Scholar 

  • Schenkman BN, Nilsson ME (2010) Human echolocation: blind and sighted persons’ ability to detect sounds recorded in the presence of a reflecting object. Perception 39:483

    Article  Google Scholar 

  • Seilacher A (1992) Vendobionta and Psammocorallia: lost constructions of Precambrian evolution. J Geol Soc Lond 149:603–613

    Article  Google Scholar 

  • Shu D (2008) Cambrian explosion: birth of tree of animals. Gondwana Res 1:219–240

    Article  Google Scholar 

  • Shu D-G, Luo H-L, Conway Morris S, Zhang X-L, Hu S-X, Chen L, Han J, Zhu M, Li Y, Chen L-Z (2001) Lower Cambrian vertebrates from South China. In: Rise of the dragon: readings from nature on the Chinese fossil record. Chicago University Press, Chicago, p 175

  • Waddington CH (1957) The strategy of the genes. George Allen & Unwin, London

  • Waloszek D et al (2007) Evolution of cephalic feeding structures and the phylogeny of Arthropoda. Palaeogeogr Palaeoclimatol Palaeoecol 254:273–287

    Article  Google Scholar 

  • West-Eberhard MJ (2003) Developmental plasticity and evolution. Oxford University Press, Oxford

    Google Scholar 

  • Wimsatt WC (1986) Developmental constraints, generative entrenchment, and the innate-acquired distinction. In: Bechtel W (ed) Science and philosophy: integrating scientific disciplines. Martinus Nijhoff, Dordrecht, pp 185–208

    Chapter  Google Scholar 

  • Wright S (1931) Evolution in mendelian populations. Genetics 16:97–159

    Google Scholar 

  • Wyles JS, Kunkel JG, Wilson AC (1983) Birds, behavior, and anatomical evolution. Proc Natl Acad Sci USA 80:4394–4397

    Article  Google Scholar 

  • Zeh DW, Zeh JA, Ishida Y (2009) Transposable elements and an epigenetic basis for punctuated equilibria. BioEssays 31:715–726

    Article  Google Scholar 

Download references

Acknowledgments

Many thanks to Colin Allen, Lisa Lloyd, and the members of the Indiana University Biology Studies Reading Group for their helpful comments on a draft of this paper.

Author information

Authors and Affiliations

  1. Cognitive Science Program, Indiana University, Bloomington, IN, USA

    Michael Trestman

Authors
  1. Michael Trestman
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Michael Trestman.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Trestman, M. The Cambrian Explosion and the Origins of Embodied Cognition. Biol Theory 8, 80–92 (2013). https://doi.org/10.1007/s13752-013-0102-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s13752-013-0102-6

Keywords

Search

Navigation