Death and Rebirth: The Role of Extinction in Evolution

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August 14, 2012 Tags: History of Life

Today's entry was written by Dennis Venema. You can read more about what we believe here.

Death and Rebirth: The Role of Extinction in Evolution

When they imagine evolution, many Christians picture novelty: new species arising over time, or speciation events. But as the most recent Southern Baptist Voices exchange makes clear, many Christians also focus on the role of death in evolution—something that can be a stumbling block to seeing it as a means by which a good God creates. This is especially true when we imagine the death of individual creatures in fierce competition for limited resources, whether such struggle takes place on the savanna or elsewhere.

In his essay for that series, Jeff Schloss addressed the question of whether animal death is a natural evil, but also noted that such theological considerations aside, death does not actually “drive evolution” in the way most people imagine—especially when they think of violence in the natural world. This more complicated sense of death’s role is partially the result of modern evolutionary science recognizing the importance of cooperation and inter-relation among species, rather than just direct competition. But just as important is the knowledge that evolution is significantly shaped not by the deaths of individual creatures, but by extinction, the loss of species over time. In this post, we explore some aspects of how extinction acts as both a destructive and creative force in evolutionary history, including the evolutionary history of mammals.

Sporadic extinction

Extinction is actually a common feature of life on earth when viewed over long (e.g. geological) timescales. By some estimates, over 99% of the species that have ever lived have gone extinct. One factor that promotes extinction is the fact that evolution does not produce species that are optimally adapted to their environment, but only better adapted than their local competitors. Invasive species testify to this fact: local (endemic) species are not always the best-adapted species for their own environment. Examples abound where species from other environments are actually better-suited to out-compete endemic species. Here in my own province, the invasive Himilayan blackberry (Rubis discolor) easily outcompetes many endemic species. If endemic species were optimally adapted to their environment, this would not be possible, as they would outcompete all exotic species. Instead, exotic species, by chance, might be better adapted to an ecosystem they did not evolve in. These exotics may be capable of eliminating endemic species altogether.

Such an extinction event (of a single species, or perhaps a handful of species) alters the environment of other remaining species in an ecosystem. This, in turn, may influence the ability of some of these remaining species to reproduce compared to other species. For example, the extinction of a competitor might allow a species to increase in population size. Conversely, the extinction of a species that provides a benefit (such as a pollinator) may reduce a species in number. As the ecosystem landscape shifts due to loss of species, new biological opportunities, or niches, might arise. These new niches are then available to support new species to fill them.

Extinction, en masse

One way to appreciate how extinction opens up new niches is to examine mass extinction events – geologically brief periods where large numbers of species go extinct at the same time. Over the history of life on our planet there have been several mass extinction events. The largest such event, at the end of the Permian (~250 million years ago) appears to have been caused, at least in part, by intense volcanic activity over several hundred thousand years. This activity likely shifted CO2 levels and eventually led to a “runaway” greenhouse effect that dramatically raised global temperatures and led to anoxic (i.e. oxygen-depleted) oceans, though the exact contributions of these varied factors remains an area of scientific debate. What appears certain is that during this period environmental changes were too rapid for most species to keep evolutionary pace with, and as a result over 90% of the world’s species alive at that time went extinct. Obviously this represents destruction of biodiversity on an unimaginable scale, and the destructive effects of this event are with us to this day.

Speciation, en masse

This destruction, however, is not the whole story. Following on from the Permian mass extinction, we observe a steady increase in new species. These are species previously unknown in the fossil record. In fact, this pattern (a “radiation” of new species following an extinction event) is the rule, not an exception – we see the same effect after every mass extinction in the fossil record. Extinction is a driving force for novelty.

Perhaps the most famous mass extinction event is the Cretaceous – Paleogene (KPg) extinction, and it too follows this standard pattern. This mass extinction took place 65 million years ago when an asteroid ~10 kilometers in diameter struck the Yucatan peninsula. (Note: this event was formerly known as the Cretaceous – Tertiary (K-T) extinction, but that terminology is in decline within the scientific community). This extinction event is famous since it is the one that eliminated the dinosaurs (with the exception of the ancestors of modern birds). As with the Permian extinction, the elimination of so many species shifted the evolutionary landscape for the remaining species, and the result was a burst of speciation that appears rapid when viewed in geological time. Significantly for our own species, following the KPg extinction event is a burst in mammalian speciation, as small mammals that survived the event diverge and fill niches left empty by the dinosaurs. Without this event, the trajectory of mammalian evolution would certainly look very different.

Clearing the deck, and re-filling the niches

One interesting fact to note is that biological features that make a species resistant to usual, sporadic extinction are not necessarily the same features that will be useful during a mass extinction event. While species are continually under selection at the local level, there is no mechanism for (pre) selection to survive a mass extinction. As such, only species that happen to have the right combination of traits will survive, and often spread widely after a mass extinction. These so-called “disaster species” are usually generalists, and will later be displaced by more specialized species as they arise. As such, where sporadic extinction allows for more gradual turnover in species, mass extinction events are major “resets” of evolution that can radically shift what constitutes “well adapted” in a geological eyeblink. For mammals at the KPg boundary, small body size and an omnivorous diet (including the ability to scavenge detritus) were the “winning” combination of traits that allowed them to survive where larger, more specialized animals (think Tyrannosaurus rex) could not. From this rather humble station, mammals would come to dominate the world’s ecosystems over the coming eons – including a lineage that would someday lead to our own species. Far from only a destructive force, extinction is a powerful mechanism to allow evolutionary innovation, and one that was of significant importance to us.

For further reading:

Meredith, R.W. et al (2011). Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification. Science 334; 521-524.

Fastovsky, D.E. (2005). The Extinction of the Dinosaurs in North America. GSA Today (15); 1052-5173.

Benton, M.J. and Twitchett, R.J. (2003). How to kill (almost) all life: the end-Permian extinction event. TRENDS in Ecology and Evolution (18); 358-365.


Dennis Venema is professor of biology at Trinity Western University in Langley, British Columbia. He holds a B.Sc. (with Honors) from the University of British Columbia (1996), and received his Ph.D. from the University of British Columbia in 2003. His research is focused on the genetics of pattern formation and signaling using the common fruit fly Drosophila melanogaster as a model organism. Dennis is a gifted thinker and writer on matters of science and faith, but also an award-winning biology teacher—he won the 2008 College Biology Teaching Award from the National Association of Biology Teachers. He and his family enjoy numerous outdoor activities that the Canadian Pacific coast region has to offer. Dennis writes regularly for the BioLogos Forum about the biological evidence for evolution.


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Roger A. Sawtelle - #71886

August 14th 2012

One thing that science has made clear and that is that God did not create our world in a short period of time.  That means that our planet has gone through many changes.  This includes changes in geography, changes in climate, and changes in life forms.

Darwinism seems to think that genes through mutation create new life forms.  However this goes against clear observation that new life forms are created when new ecological niches are created by ecological change.  This is the reason why Dawkins is wrong in his understanding of how evolution works.

There is of course a flip side of this.  Species are lost as climate and the earth changes and ecological niches are lost and replaced.  Even so the chain of life is not broken because every species plays a role in their particular niche in their particular time, just as every particular person does the same. 

This is all part of God’s plan that we can see dimly now, but will be crystal clear at the End.  This is far different from the way Darwin and Dawkins see life playing out which is the reason why ecological evolution is much better than Darwinism.  

 


George Bernard Murphy - #71894

August 14th 2012

You know Roger I think ANY specimen of DNA can eventually evolve into ANY ORGANISM.

It is a slow process. But you just change that little nucleotide at a time.

 Think of it like a set of tinker toys.

 Anything made out ot tinker toys, a little wagon,. a tower,  a dog,.whatever,..... can be changed into any other thing that can be made out of tinker toys ,... by just replacing it with one piece at a time.

 DNA evolves the same way,... one piece at a time,.. so that any piece of DNA can be converted into ANY OTHER PIECE OF DNA in slow steps.

 

 it is an amazing little molecule. God made it [although whether He made it here or on some other planet,..we do not know],.. and….

He dumped a starter dose here [possibly in the ice of meteors like the ones that showered the earth last night.]

All living things developed from it. Cool huh?

and if you create additional ecologic niches,..... new and even different living things will develope to live there.


Roger A. Sawtelle - #71897

August 14th 2012

George,

Yes, DNA is cool.

I think that it is more like a language than a tinker toy made out of letters, words, syntax, and punctuation. 

And yes it is very adaptable.  It is one of God’s most amazing inventions, even though we are biased being made of it ourselves.   


Joriss - #71901

August 14th 2012

Very interesting articles by Schloss and Venema. But I don’t see the relevance with the goodness of God. Even if evolution works less through conflict than through cooperation and inter-relation between species and less through the death of individuals than through extinction of species over time, than there will still be many individuals of an endemic species that will die because a species, better adapted though coming from outside, will make life impossible for that endemic species, that will go extinct. So even if there is less suffering than when death should be the very engine of evolution, death will still play a role in all this.
And when you consider the two great mass extinctions Venema is writing about, you can see this role is very great. A mass extension of dinosaurs by a disaster was needed to pave the way for the evolution (creation) of mammals and eventually humans. So what’s the theological difference? It is creating by destruction.
If death is not a means of evolution, it is at least a condition for evolution. In both cases it is in God’s hands, for He is also the creator of these conditions. All conditions, of the biological world and of the non-biological world are involved in creation. So death may not be a direct means of evolution, but in any case it is a means of creation - if scientists are right.
What kind of creatures were those ones that were evolved just before us, before God gave His image to them? Scientists say there were never two people of which we all are descendants. So there must have been a kind of human species that just like animals could hunt and kill and fight and, being sort of humans, make war.
So before God created humans in the image of God, there had never been a bit of peace on this earth. And since the fall there has never been.
Besides, predation is part of keeping species strong and healthy, by eliminating the weaker ones, and leaving the ones with good conditions, giving them more chance to survive and evolve, so predation is also an indirect condition in the chain of conditions that is needed for evolution/creation.

So I don’t see how this new vision of evolution can make the pill of death involved in it, somewhat sweeter, nor does it, in my opinion, make difference with regard to the issue of God’ s goodness.
So I think we still have to choose a clear choice:
1. We accept that God created, directly or indirectly, by means of death and suffering and still is a good and loving God, how difficult this ever will be for us, so we can accept evolution.

2. We can not accept or believe that a good God can create in such a way, so we cannot accept evolution.


Dunemeister - #71906

August 15th 2012

Death plays a role in our salvation, too. Although God the Father didn’t plan or intend or wish Jesus’ death, Jesus’ death was going to be inevitable if he chose to be faithful to his mission to inaugurate the kingdom of God (which he did) AND if his opposition continued to resist his mission (which it did). Thus Jesus’ death was a byproduct of God’s desire to renew humanity and destroy death and everything else that mars creation, and Jesus’ desire to see that happen, come what may. What if something similar is going on in the creation and distribution of life? Death is out there, but God is not culpable for it. It’s a byproduct of finite creatureliness. I haven’t thought this out very thoroughly, but perhaps there is a third option this way (or perhaps this is a version of your first option, I don’t know).


HornSpiel - #71907

August 15th 2012

It is hard to keep from imagining that these mass extinction events, as opposed to the “normal” extinction events, are providential. When and where a 10km asteroid crashes into the earth is seemingly random. Yet I think it must have been also been a divinely orchestrated “reset.”

I also find it interesting that in the deluge and Armageddon Scripture contain two prominent divine “resets.” Theologically speaking do these pictures of mass destruction in the sacred narrative have any impact on the way we see mass extinction events in natural history?


Jon Garvey - #71928

August 15th 2012

Hornspiel

I’d be hesitant to compare the K-T event etc with the Flood or the final conflagration directly. The latter two have direct reference to the purging of evil. The flood, theologically, is a reversion to chaos (and as you say, a “reset” in some sense). The latter is a transformation both purging creation and auguring in a new creation entirely.

The parallel with geological catastrophes that does, to me, seem valid is the affirmation that all these events are under God’s control and serve his purposes. Granted God’s ordination of animal death in the economy of the creation, then the redirection of biology via such events is not especially problematic. Have you come across Mike Gene’s ideas of the first organisms “terraforming” the earth before giving way to other suites of organisms moving in our direction?

What seems to me sub-christian is the idea that God watched in horror as an unpredicted asteroid crashed into the Caribbean, and breathed a sigh of relief when some shrews survived, making a mental note to send Jesus as a mammal rather than a reptile as in the original plan.

So whatever his purposes in doing it that way, mass extinction events need to come under his governing providence, or he is a sub-deity whose grandiose plans for our glorification are just an asteroid away from coming to nothing. That has some implications for our view of God’s action and scientific law.


Joriss - #71938

August 15th 2012

Dunemeister,

Yes, death plays a big role in our salvation. I think it was a byproduct of God’s desire indeed to renew humanity and destroy death and restore creation. But as you know: it was needed because of the sin and the opposition of mankind against God’s government. Why should death have been part of creation itself, if God is good and there was no sin? Then God intended it to do so, so can He be a good God? That is the difficult question. So I think we still have to choose one of the two options.

HornSpiel,

Also here Armageddon and the Flood have to do with sin and are in my opinion not simply comparable with biological death by mass extinction.


Francis - #71939

August 15th 2012

I’m back, for the time being.

I was unable to join with the flood of fascinating commentary of the last week, as I was unavoidably detained. During my detention, I may have evolved to the point where I’m no longer capable of much more than questions.

I have nine.

“One factor that promotes extinction is the fact that evolution does not produce species that are optimally adapted to their environment, but only better adapted than their local competitors. Invasive species testify to this fact: local (endemic) species are not always the best-adapted species for their own environment…  Instead, exotic species, by chance, might be better adapted to an ecosystem they did not evolve in. These exotics may be capable of eliminating endemic species altogether…This, in turn, may influence the ability of some of these remaining species to reproduce compared to other species… Conversely, the extinction of a species that provides a benefit (such as a pollinator) may reduce a species in number.”

1) What does this say for the predictive power of the theories of natural selection and evolution (predictive power being the strongest validation for a scientific theory)?

“…mass extinction events. The largest such event, at the end of the Permian (~250 million years ago) appears to have been caused, at least in part, by intense volcanic activity over several hundred thousand years…What appears certain is that during this period environmental changes were too rapid for most species to keep evolutionary pace with, and as a result over 90% of the world’s species alive at that time went extinct.”

2) What percentage of fossils world-wide is near volcanoes, both active and inactive?

3) Does it appear certain, then, that 100% of extant species descended from the 10% that remained 250 million years ago?

“In fact, this pattern (a “radiation” of new species following an extinction event) is the rule, not an exception.”

4) What was the extinction event that led to what is probably the greatest species radiation – the Cambrian Explosion?

5) Given that beneficial/advantageous mutations are required for new and “lasting” speciation, why would the mutation rate for such accelerate significantly to allow the species “radiation”?

“This mass extinction took place 65 million years ago when an asteroid ~10 kilometers in diameter struck the Yucatan peninsula…This extinction event is famous since it is the one that eliminated the dinosaurs (with the exception of the ancestors of modern birds).”

6) Does the Yucatan have a 10 kilometer-wide crater?

7) How would an event in one small part of the world (the Yucatan) cause the elimination of dinosaurs (from the small Saltopus to the titanic T. Rex) all around the world?

8) What was the ancestor of birds and why would it not likewise be eliminated?

“From this rather humble station, mammals would come to dominate the world’s ecosystems over the coming eons – including a lineage that would someday lead to our own species.”

9) Why does Genesis have Adam being formed from the ground and not from one of the earlier-created beasts (e.g. from the rib of one of the animals)?


Ed Babinski - #71943

August 15th 2012

EXTINCTION, EN MASSE

GOD SHAKING HIS ETCH-I-SKETCH? 

SNEEZING? 

DROPPING STUFF AFTER EVOLVING WHOLE NEW SPECIES AND ECOSYSTEMS, AND THEN OOPS?

 


wesseldawn - #71976

August 16th 2012

Extinction was random in times past with the animal population not at the mercy of God (for surely a benevolent God would have seen to their care) but mother nature.

More recently however, neither God nor mother nature can be blamed as human meddling is increasingly the cause of extinction: the Dodo Bird comes readily to mind! Of late the Polar Bear population is being threatened by premature melting ice caused by global warming. 

In cases where humans are the obvious cause, I don’t believe it can be called evolutionary extinction.


HornSpiel - #71986

August 17th 2012

Wesseldawn,

God’s command to Adam and Eve in Genesis 1 to “rule over” all the different creatures and his command in Genesis 2 to care for the Garden imply that God requires Man to care for His creation. Would you not agree that what you call human meddling could also be thought of as human failure to be good stewards of the earth?

On the other hand, what do you say to mass extinction events like the asteroid that hit the earth 65 MYA? Was that random? Was that mother nature? Was not God responsible? Many Bible passages imply that God takes responsibility for disasters. We may not understand their purpose, but I don’t think the good nature of God as revealed in Scripture requires Him “benevolent” in the way you say he is. Instead, natural disasters are providential and serve God’s greater purposes in ways we may never know.

God made the world a dangerous place. So it is our responsibility to learn and provide safety for all its inhabitants. That can take the form of developing and enforcing earthquake safety codes to protect people in earthquake danger zones. Or can take the form of working to develop reliable, green energy sources to try and arrest the global warming that is threatening polar bears and who knows how many other species.


wesseldawn - #72016

August 18th 2012

HornSpiel,

Yes I agree that human failure to be good stewards of the earth is the problem. More than that though (on a higher level) are evil principalities and powers that work to undermine all that is good.

God is responsible for disasters. God made the world a dangerous place.

God kills? God maims? Would you equate the merciful and beneficient God with evil?

For God so loved the world  (John 3:16)

Evil came into the world because of the fall and because Satan is the god of this world (2 Cor. 4:4, Eph. 2:2), not because God wanted it that way.


Roger A. Sawtelle - #72031

August 18th 2012

wesseldawn,

Sin is evil.  Death is not.  Creatures die, including plants, animals, microbes, and humans.  They die because they are physical and thus mortal. 

As I told you before Satgan is not god of the world, he is god of this age, which means Satan did not create death.

Gode did noty create humans to be weak, lazy, and stupid.  Life is not easy.  Life is a challenge.  God believes in “tough love,” not spoiling people. 


Francis - #72033

August 18th 2012

Does no one have any answers for any of my nine questions above?


W W W - #76423

February 7th 2013

What kind of creatures were those ones that were evolved just before us, before God gave His image to them? Scientists say there were never two people of which we all are descendants. So there must have been a kind of human species that just like animals could hunt and kill and fight and, being sort of humans, make war.
So before God created humans in the image of God, there had never been a bit of peace on this earth. And since the fall there has never been. 
Besides, predation is part of keeping species strong and healthy, by eliminating the weaker ones, and leaving the ones with good conditions, giving them more chance to survive and evolve, so predation is also an indirect condition in the chain of conditions that is needed for evolution/creation.

So I don’t see how this new vision of evolution can make the pill of death involved in it, somewhat sweeter, nor does it, in my opinion, make difference with regard to the issue of God’ s goodness.


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