Co-evolution, the answer to world hunger?

9.5 BILLION- That is likely what the global population of humans will be by the year 2050. Is that not far away? Do I need to be concerned about this?

Well yes, you should be. As much as it would be convenient, there are unfortunately a finite supply of resources on planet earth and these are running out. Scientists warn that ecological systems are approaching critical thresholds or “tipping points” beyond which alterations to these systems due to human induced impacts will result in runaway, irreversible changes (1).

In 1964, Peter Raven and Paul Erhlich published a study which introduced the concept of coevolution (More information on coevolution) and now five decades later, with the science community taking a renewed interest in coevolution we see a return to butterflies and some fascinating work being done on understanding the mechanisms responsible for this phenomenon (2).

Some important findings from this research, investigating the coevolution between cabbage plants (Brassicales) and butterflies (Pieridae) have implications in the production of healthier, more pest-resistant food crops. This is because by understanding the mechanisms by which these species co-evolved, scientists can artificially give plants the edge-a greater advantage than would be possible by natural selection alone- a new, faster and in all ways superior pair of “running shoes” to those of the pesky critters which eat them. This is known as the evolutionary arms race or the way my Professor always put it, the Red Queen Hypothesis. Basically that the faster alice runs the faster the queen runs, in a continuous cycle. What this refers to in biological terms is the fact that when a plant species or any sort of target species that is adversely affected by another, gains some sort of adaptation that makes it more resistant to this “threat” , the attacking species undergoes a reciprocatory change that allows it to continue feeding on its preferred target. That is the evolutionary arms race, a cornerstone of evolutionary biology. This continuous cycle is what scientists now seem to want to break heading into the future.

What Edger and colleagues found is that during the 90 million year history between the ancestor of cabbage and the white cabbage butterfly is that whenever the plant evolved a mechanism to deter herbivory such as in the production of glucosinolates (sharp flavour we experience in mustard and horse-radish) , the butterflies evolved the ability to detoxify the poisonous substances soon after. The butterflies evolved counter-tactics to out-manoeuvre the devious mechanisms deployed by the cabbage, and so have over millions of years undergone this exchange. Interestingly this back-and-forth dynamic also gave rise to a greater diversity of cabbage relatives (thank you clever, little butterflies) and butterfly species. (coevolutionary diversification).

For blog-coevolution genetics

The power to control the development of new genes? It is a crazy thought! and would give us a degree of control that we have not historically possessed. While fascinating I wonder what knock-on ecological consequences this could have…Could we essentially be deciding which species survive and which do not? As by conferring a large enough advantage to the species we deem as “worthy” the co-evolving species will simply not be able to catch up. Those new running shoes are too damn fast!

Cited:

1: Barnosky, A.D. et al. (2012) Approaching a state shift in Earth’s biosphere. Nature 486, 52–58
2: Edger, P.P. et al. (2015) The butterfly plant arms-race escalated by gene and genome duplications. PNAS 112, 8362–8366
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