Newest Oldest Living Thing?
Is this seagrass patch really as old as they say?
Published: 23 February 2012 (GMT+10)
Recently, newspapers were abuzz with a new headline claiming that the oldest living thing on earth had been discovered,1 but this was not the first time statements like this have been made. Previous claimants to the title include bristlecone pines,2,3 huon pines,4,5 and Norway spruces.6 This time, the contender is a seagrass. It is yet another plant, but probably unfamiliar to most people. It’s claimed to be up to 200,000 years old.
Seagrasses live throughout the world’s oceans. Their slender green blades tend to bend and wave in the current, creating pleasantly idyllic scenes for snorkelers and swimmers who happen upon a seagrass meadow in clear, shallow water. They are also a rich habitat harboring many marine species, such as the stinging hydroids that have surprised many a snorkeler foolish enough to brush against the swaying fronds without looking. They are also a primary food source for many marine creatures. Thus, they are important for many of the world’s coastal salt water ecosystems.
What is it about them that made recent headlines? A team of Australian scientists studying patches of the seagrass, Posidonia oceanica, in the Mediterranean Sea were astonished to find genetically identical plants separated by up to 15 km.7 Because they are flowering plants (yes, underwater!), seagrasses can reproduce sexually. However, to get plants with identical genotypes, asexual reproduction must occur and this is usually due to breakup of an original clump of plants by waves or herbivores. Plant fragments can drift to another location, put down roots, and begin to grow again. Alternatively, plants can send out runners and sprout new leaves some distance from the original plant. Vegetative growth like this can create monospecific patches (i.e., all plants are genetically identical), but this species also grows slowly. Computer models indicated the clones could be as old as 10,000 to several tens of thousands of years.
In this particular case, we would do well to consider several caveats before drawing any conclusions. It would have been good for the newspaper reporters to have done this also, but provocative reporting apparently sells more papers than careful analyses. First, even though the authors of the study provided age estimates for several clones separated by up to 15 km, they specifically stated that vegetative growth was unlikely to answer how they got that large. Why? Because to be up to 200,000 years old, the seagrasses would have had to live through dramatic swings in sea level and salinity caused by ice ages.8 Since they live in shallow water, they are now living on what was dry land a mere 10,000 EYO (evolutionary years ago). The Mediterranean was quite a different place back then, with the ocean being drawn down several hundred feet, the Mediterranean was one time a freshwater lake (on the surface) with a waterfall leading to the Atlantic. Under the surface was stagnation. This is similar to the current situation in the Black Sea, which has freshwater on top and anoxic, stagnant salt water below. Thus, this grass is not older than the end of the last ice age, according to their own rules. Why, then, did most newspaper reports simply accept these large age estimates without question?
Second, if vegetative growth is unlikely to account for the distribution of clone mates, asexual propagation must be the answer. P. oceanica has few natural predators, so storms, waves, and currents are the most likely culprit. Waves and currents can sometimes create a hollow depression in the sand patches that seagrasses love so much. This can then be excavated laterally, and sometimes quite swiftly, causing the patch to fragment quickly. Currents can then carry away sections of seagrass, roots and all, to other locations. When a larger clump breaks into multiple smaller clumps, lateral growth is accelerated because a clump can only grow from the edges outward. If a stand of seagrass can grow faster than sand erosion caused by currents, it can continually spawn new clones. If not, it will be washed away. Of course, this does not apply to patches in sheltered environments.
Third, genetics cannot tell how old something is. The fact that they found genetically identical plants spread across a wide range tells us little about their age. Also, they sampled a limited number of markers (short repetitive sections called ‘microsatellites’) in the genome. It is possible that they missed some genetic structure in the seagrass population by choosing incorrect markers or by not sequencing enough markers. This has occurred before in studies using microsatellites in other species. Finally, the authors noted no somatic mutation in the genomes of the seagrasses studied (in other words, they had no samples with more than one reading at any particular microsatellite). This could either mean that the mutation rate at the locations studied is low (the Australian scientists’ contention), or that the clones are not that old (my contention).
Fourth, so far, all we know is that genetically identical plants can be found across a wide range. How do we assign an age to each clone? To do this, the scientists designed a computer model and tried to base it on what they knew about the plants (e.g., previously published measurements of growth rate, etc.). Yet, any such model is constrained by many unknowns and that is where the ‘art’ (some might call it ‘spin’) comes in. A scientist must first decide which parameters are most relevant to a model, and then assign a range of acceptable values to each. Usually, the model is tested against experimental evidence to see how well it explains the known data. Then, and this is the important part, if it explains today’s data well, the model is used to extrapolate into the distant past. Since there are inherent uncertainties and estimates in the model, and since there are possibly many unknown confounding parameters remaining to be discovered, it is easy to see that predictions should diverge further and further from reality as they attempt to model farther back in time.
Fifth, clonal reproduction is a dead-end evolutionary strategy. An organism might be able to fill a particular niche with copies of itself, but environmental change will eventually occur and the organism is eventually going to die as a consequence. Is this not the reason we are told sexual reproduction evolved in the first place?9 Is it not better for an organism to split up its genes into various copies and combinations with another individual in order to maximize genetic diversity and ensure future phenotypic variation so that natural selection has something with which to work? Since these clones are doomed to eventual extinction anyway, and since there are so many unknowns inherent in the age calculations, one wonders why all the fuss is being made about their age.
In an inevitable turn towards environmental activism, the various reporters bemoaned the fact that this old grass clone is threatened with extinction, but so what! They give no justification for their concerns, and, under evolutionary theory, there are none. The only thing possibly guiding them is fear of the unknown. However, we can derive meaning for existence and a reason for caring about our environment from a straightforward reading of the Bible.10 According to the Bible, God made us in His image, put us in a special place in His creation, and gave us a way of escape when we rebelled. Not only that, but He also put us as caretakers over the world in which we live.
Should we care about seagrasses? Yes, for they fall under our purview. Yet, they are of little importance in the grand scheme of things. And, since we live in a sin cursed world, everything is doomed to extinction anyway. Anything remaining alive at the return of Christ will be burned up. Jesus promised to return for his children (his “bride”) and remake the world. In the meantime we are stewards of this earth and we care for the creation. Therefore, let us soberly assess our situation and that of all created species and base our concerns on a proper understanding of history and the future destiny of all life.
Are these seagrass plants as old as claimed? As we have seen above, these age claims are based on unprovable assumptions and flimsy calculations. There is no reason to accept what is being reported as is. Even the scientists involved were much more cautious in their conclusions than what appeared in the public press, so we can dismiss most of the reporting as nothing more than an attempt to get people to read more newspapers and web articles. The scientists still believe these plants are very old, but they base their conclusions on a suite of genetic and ecological models which are notoriously subject to revision. The genetic data indicate the seagrass plants are young. In fact, the data is entirely compatible with and age of less than 4,000 years old—an age based on the true earth history as derived from God’s word.11
- Pearlman, J. ‘Oldest living thing on earth’ discovered. The Telegraph, London, Feb 9, 2012; http://www.telegraph.co.uk/science/9066393/Ancient-seagrass-Oldest-living-thing-on-earth-discovered-in-Mediterranean-Sea.html Return to text.
- Woodmorappe, J. Field studies in the ancient bristlecone pine forest. Journal of Creation 17(3):119-127. Return to text.
- Matthews, M. Evidence for multiple ring growth per year in Bristlecone Pines. Journal of Creation 20(3):95-103, 2006. Return to text.
- Anonymous. Living tree 8,000 years older than Christ . Creation 17(3):26–27, 1995. Return to text.
- Bates, G. Patriarchs of the forest. Creation 25(1):10–13, 2002. Return to text.
- Wieland, C. A closer look at a claim about the world’s oldest trees allegedly older than the biblical date of creation. Creation 31(2):23, 2009. Return to text.
- Arnaud-Haond S, Duarte CM, Diaz-Almela E, Marba N, Sintes T, et al. Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica. PLoS ONE 7(2): e30454, 2012. Return to text.
- See Ice age Questions and Answers. Return to text.
- See Chapter 11 of Sarfati J, Matthews M. Refuting Evolution 2. Creation Book Publishers, 2011. Return to text.
- See Environmentalism Questions and Answers. Return to text.
- See Batten, D. It’s not science, Feb 28, 2002. Return to text.