The Prelapsarian Acacia and the Good Creation: On the Origin of Thorns

Hundreds of species of acacia have abundant thorns or spines which are modified branches. These spines may be thin and long or highly inflated at the base. The latter often are hollow at maturity and ants may live in them.

I’ve been thinking about acacia plants ever since I showed some pictures of them while leading a Sunday School class a few weeks back.   The point at the time was just to present some of the salient features of the plants that are mentioned in the Bible so that texts that use them can be better understood.  But, the thorns on acacias got me to thinking about how traditionally all thorns and thistles have been viewed as results of the curse on Adam for his sin.   In my prior article I looked at the dilemma that mimicry in organisms can be for young earth creationists.  I want to share a brief natural history of acacias with you and then pose the question, what did acacia trees look like in the prelapsarian world (ie. before the fall of Adam?

Acacias are a common name given to species of trees and shrubs of the genus Acacia although that genus has recently been divided into several groups.  There are over 1300 recognized species and innumerable varieties of acacias.   Acacias are in the bean (or legume) family of plants and so produce a type of bean pod called a legume as a fruit.    Acacias can found on all continents except Antarctica but are the most species rich in Australia.     Many acacias live in deserts and other arid regions of the world.  Let us consider some of these amazing adaptation of acacias to living in the present world.   First, like other members of the bean family, many acacias are capable of doing  nitrogen fixation is a result of bacteria that are housed symbiotically in their roots.  These bacteria have the biochemical machinery to take atmospheric nitrogen (N2) and convert it to a form that can be used by plants.   This ability allows bean plants to grow in what would otherwise be soils that could not support them due to nitrogen deficiency.  This is very helpful for life in desert soils which are frequently deprived of nutrients.

A giraffe reaching up to eat acacias. (image credit: wikipedia)

Secondly, many acacias produce thorns and many of them are covered in thorns.    Although highly specious in Australia, most species in Australia do not have thorns while those in the deserts of African and the Middle east are extremely thorny and have been called devil thickets or devil trees.   Those acacias that don’t produce thorns often have high levels of toxic chemicals in their leaves.   How are these an adaptation?  Thorns in desert acacia are obviously an adaptation to prevent the lender leaves from being eaten by herbivores.  Australia does not have native herbivores other than marsupials most of which can not reach into trees.  Australian acacias though do need protection from caterpillars and other insects and so are more likely to produce toxins in their leaves.  So the lack of thorns makes sense without evoking any relationship of the thorns to man.

You can see from the picture above that the thorns produced are often longer than the leaves themselves which is a very effective way of warding off large mouths from taking a bite on the plants.  This is especially important for desert plants that can’t afford to lose the few leaves they produce.   However, there are animals which themselves demonstrate amazing adaptations to their environment which include abilities to eat these thorny plants.  Giraffes have 20 inch long tongues which are really tough. The bottom lip is also incredibly touch and can take the poking of these thorns without much problem.   Even the inside of the giraffes mouth is adapted to eating what would be inedible food for you and I.   Giraffes can not only reach high into an acacia tree but have all the physical traits needed to take advantage of these food source.

ants and beltian boides on acacia

The yellow structures are called beltian bodies and are a protein/lipid rich structure produced either at the tips of the leaflets or in some species of acacias in place of some leaflets. The ants can clip these bodies off and carry them to their homes inside the thorns on these acacias from Central America. The ants use them as a food source. In return for the food that the plant provides the ants put up a vigorous defense of the tree including attacking any other insects or herbivores and in some cases even cutting away any other plant that comes in contact with the trees.

Some acacias in central America produce swollen thorns that are hollowed out by ants for homes.  There are multiple species of acacias that do this and each one has its own species of ant that lives in its thorns.   These acacias not only provide a home, they also provide the food for the ants which live exclusively on these trees.   That food can be in one or both of two food forms.  Beltian bodies are small protein/lipid rich structures which the leaflets will produce at their tips which the ants can clip off and carry back to their homes in the thorns.  Some acacias also produce what are called extrafloral nectarines (see picture).  These are little bumps on the petioles of the leaf that ooze sap that the ants can drink.  The only reason for this plant organ seems to be to provide the ants with food.  So the ants seem to be getting a really good deal with these trees. What does the tree get for all these favors it is doing for the ants?   Well, the ants are ferocious defenders of these trees.  If any insect or animal lands on the tree one ant will give off a pheromonal signal to the other ants and they will attack the invader and kill them or drive them away.  In the most famous case, the ants even go as far as chopping down all vegetation around the acacia tree to reduce competition with other plants.

This image shows an acacia from Costa Rica. It shows the thorns with openings for ants to enter and extra floral nectaries which are the three small red spots on the petiole leading to the compound leaf blade. (photo Valery Fuzeau)

Prelapsarian adaptations to the Fall?

Given this short background on the adaptations of acacias to their environment and other organisms lets ask the question, which of these adaptations is not a good feature of the plant?  Creation scientists tell us that any evidence of features that would be used for competition or adaptation to a world in which death and decay is present must be features which where not present or at least useful in the original creation (the prelapsarian world).  So how, according to creation scientists, do such intricate features that seem so well designed for this fallen (lapsarian) world come about?   The creation science explanation is probably best summed up in this paragraph from an article talking about a complex interaction wherein certain wasps are able to attack and anesthetize tarantellas and then use them as hosts for her larva.

The mother wasp is genetically and behaviorally programmed to locate and anesthetize a tarantula, and to carefully transfer her larval offspring to the arachnid’s body. Why does all of this work out the way it does in each life cycle of this particular kind of wasp? Because, before Adam’s fall in Eden, God cleverly and carefully planned out (consistent with His infinite foreknowledge) the innumerable details that would be needed, after Eden, to make this air-to-ground system operate successfully enough to propagate tarantula hawk wasp populations from one generation to the next.  (From James Johnson, “Slow death for a tarantula: a lesson in arachnid apologetics”,  http://www.icr.org/article/6390/).

In this case, the wasp in the Garden (and presumably outside Eden as well but that is a topic for another day), would not have attacked and killed the Taratula and would have somehow found a way to make more wasps (more of their own kind) via some non-destructive pathway.    However, for Johnson, this ability of wasps to find and use Tarantulas as hosts for their young is so intricate he believes it could only have been created this way so he proposes that God pre-programmed these wasps so that natural selection put into motion by Adam’s sin would put into motion a series of changes that God knew would happen to give these wasps this new way of propagating themselves.   Was the old way just not good enough?  Why did Adam’s sin require that wasps be reprogrammed but could not have been reprogrammed by recreation?  What is “natural selection” in this lapsarian world if this mechanism of change  had no function in the prelapsarian world.  These are difficult questions that, although they sound confident, even creation scientists get nervous talking about.

But back to the acacias. Creation scientists insist that thorns are “bad” and could have no part of a “good” creation. But how is good defined.  It appears good to them is defined more by an aesthetic informed by science rather than the scriptures themselves.  What was good is referenced  relationship to how God made things for man.  It was not good that he should be alone, it was not good that the world should be in a state of desolation and disorder and so God ordered it for man.   The thorns and thistles that are to be born “from the ground” for man are the result of his sin.   He was to eat of the fruit trees and to worship and obey in the Garden but when sent out of  Garden of Eden he would have to work the ground from once he came (remember that Adam was made outside the Garden and then placed in the Garden).  That work would be inhibited by the thorns and thistles produced by the plants that were outside the Garden.  Where they there already or where they newly created by God after the fall?  I do not want to explore the land “outside of Eden” or even outside the Garden of Eden just yet because I have a whole series of  future posts planned to explore the important question of the extent of Eden on the earth both before the fall.

Before exploring the nature of thorns a bit more I would just ask you to reflect on the purpose of thorns and the purpose of the curse on Adam.  If giraffes did not need long necks to reach food and they did not need resistant mouths for spines did they not have long necks, very long tongues and exceedingly tough skin in their mouths in the prelasparian world?   If some ant species only live on acacias where did they live when acacias had no spines?  If acacias have hundreds of genes that code for highly specialized features that allow to survive in extreme deserts what purpose did these genes and features serve in the idyllic “good creation” as envisioned by creation science.   Regarding the latter, most creation scientists don’t believe deserts existed prior to the flood despite the presence of fossilized features of plants that suggest adaptations to deserts.

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Comments

  1. It gets even more complicated. Seems that the acacia actively makes the ant dependent on it by secreting an enzyme inhibitor in the EFN. http://news.nationalgeographic.com/news/2013/11/131106-ants-tree-acacia-food-mutualism/

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