Quotes & Sayings

We, and creation itself, actualize the possibilities of the God who sustains the world, towards becoming in the world in a fuller, more deeper way. - R.E. Slater

There is urgency in coming to see the world as a web of interrelated processes of which we are integral parts, so that all of our choices and actions have [consequential effects upon] the world around us. - Process Metaphysician Alfred North Whitehead

Kurt Gödel's Incompleteness Theorem says (i) all closed systems are unprovable within themselves and, that (ii) all open systems are rightly understood as incomplete. - R.E. Slater

The most true thing about you is what God has said to you in Christ, "You are My Beloved." - Tripp Fuller

The God among us is the God who refuses to be God without us, so great is God's Love. - Tripp Fuller

According to some Christian outlooks we were made for another world. Perhaps, rather, we were made for this world to recreate, reclaim, redeem, and renew unto God's future aspiration by the power of His Spirit. - R.E. Slater

Our eschatological ethos is to love. To stand with those who are oppressed. To stand against those who are oppressing. It is that simple. Love is our only calling and Christian Hope. - R.E. Slater

Secularization theory has been massively falsified. We don't live in an age of secularity. We live in an age of explosive, pervasive religiosity... an age of religious pluralism. - Peter L. Berger

Exploring the edge of life and faith in a post-everything world. - Todd Littleton

I don't need another reason to believe, your love is all around for me to see. – Anon

Thou art our need; and in giving us more of thyself thou givest us all. - Khalil Gibran, Prayer XXIII

Be careful what you pretend to be. You become what you pretend to be. - Kurt Vonnegut

Religious beliefs, far from being primary, are often shaped and adjusted by our social goals. - Jim Forest

We become who we are by what we believe and can justify. - R.E. Slater

People, even more than things, need to be restored, renewed, revived, reclaimed, and redeemed; never throw out anyone. – Anon

Certainly, God's love has made fools of us all. - R.E. Slater

An apocalyptic Christian faith doesn't wait for Jesus to come, but for Jesus to become in our midst. - R.E. Slater

Christian belief in God begins with the cross and resurrection of Jesus, not with rational apologetics. - Eberhard Jüngel, Jürgen Moltmann

Our knowledge of God is through the 'I-Thou' encounter, not in finding God at the end of a syllogism or argument. There is a grave danger in any Christian treatment of God as an object. The God of Jesus Christ and Scripture is irreducibly subject and never made as an object, a force, a power, or a principle that can be manipulated. - Emil Brunner

“Ehyeh Asher Ehyeh” means "I will be that who I have yet to become." - God (Ex 3.14) or, conversely, “I AM who I AM Becoming.”

Our job is to love others without stopping to inquire whether or not they are worthy. - Thomas Merton

The church is God's world-changing social experiment of bringing unlikes and differents to the Eucharist/Communion table to share life with one another as a new kind of family. When this happens, we show to the world what love, justice, peace, reconciliation, and life together is designed by God to be. The church is God's show-and-tell for the world to see how God wants us to live as a blended, global, polypluralistic family united with one will, by one Lord, and baptized by one Spirit. – Anon

The cross that is planted at the heart of the history of the world cannot be uprooted. - Jacques Ellul

The Unity in whose loving presence the universe unfolds is inside each person as a call to welcome the stranger, protect animals and the earth, respect the dignity of each person, think new thoughts, and help bring about ecological civilizations. - John Cobb & Farhan A. Shah

If you board the wrong train it is of no use running along the corridors of the train in the other direction. - Dietrich Bonhoeffer

God's justice is restorative rather than punitive; His discipline is merciful rather than punishing; His power is made perfect in weakness; and His grace is sufficient for all. – Anon

Our little [biblical] systems have their day; they have their day and cease to be. They are but broken lights of Thee, and Thou, O God art more than they. - Alfred Lord Tennyson

We can’t control God; God is uncontrollable. God can’t control us; God’s love is uncontrolling! - Thomas Jay Oord

Life in perspective but always in process... as we are relational beings in process to one another, so life events are in process in relation to each event... as God is to Self, is to world, is to us... like Father, like sons and daughters, like events... life in process yet always in perspective. - R.E. Slater

To promote societal transition to sustainable ways of living and a global society founded on a shared ethical framework which includes respect and care for the community of life, ecological integrity, universal human rights, respect for diversity, economic justice, democracy, and a culture of peace. - The Earth Charter Mission Statement

Christian humanism is the belief that human freedom, individual conscience, and unencumbered rational inquiry are compatible with the practice of Christianity or even intrinsic in its doctrine. It represents a philosophical union of Christian faith and classical humanist principles. - Scott Postma

It is never wise to have a self-appointed religious institution determine a nation's moral code. The opportunities for moral compromise and failure are high; the moral codes and creeds assuredly racist, discriminatory, or subjectively and religiously defined; and the pronouncement of inhumanitarian political objectives quite predictable. - R.E. Slater

God's love must both center and define the Christian faith and all religious or human faiths seeking human and ecological balance in worlds of subtraction, harm, tragedy, and evil. - R.E. Slater

In Whitehead’s process ontology, we can think of the experiential ground of reality as an eternal pulse whereby what is objectively public in one moment becomes subjectively prehended in the next, and whereby the subject that emerges from its feelings then perishes into public expression as an object (or “superject”) aiming for novelty. There is a rhythm of Being between object and subject, not an ontological division. This rhythm powers the creative growth of the universe from one occasion of experience to the next. This is the Whiteheadian mantra: “The many become one and are increased by one.” - Matthew Segall

Without Love there is no Truth. And True Truth is always Loving. There is no dichotomy between these terms but only seamless integration. This is the premier centering focus of a Processual Theology of Love. - R.E. Slater


Note: Generally I do not respond to commentary. I may read the comments but wish to reserve my time to write (or write from the comments I read). Instead, I'd like to see our community help one another and in the helping encourage and exhort each of us towards Christian love in Christ Jesus our Lord and Savior. - re slater

Thursday, September 27, 2012

What Do We Mean by Speciation (Commonly referred to as Micro- and Macro- Evolution)? Part 2 of 2

Continued from -
(Commonly referred to as Micro- and Macro- Evolution)?
Part 1 of 2

Speciation and Macroevolution
by Biologos
February 23, 2012
Today’s entry is part of our Video Blog series. For similar resources, visit our audio/video section, or our full "Conversations" collection. Please note the views expressed in the video are those of the author, not necessarily of The BioLogos Foundation. You can read more about what we believe here.
Today's video featuresKelsey Luoma. Kelsey Luoma is a graduate of Point Loma Nazarene University in San Diego, California, where she received a bachelor's degree in biology. She plans to continue her education in medical school. As an evangelical Christian and student of biology, Luoma is very interested in resolving the conflict between faith and science. She has spent two summers working as a student intern for BioLogos. In the future, she hopes to serve internationally as a physician.
In our last two BioLogos podcasts, we looked at the question of transitional fossils and the genetic evidence for evolution. In our final installment of this three part series, we move on to the question of speciation and macroevolution. A common challenge to evolutionary theory is that while life does indeed change over time (what is known as microevolution), no one has ever seen one species evolve into another species (macroevolution). For example, no one has seen a dog evolve into something other than a dog. Because speciation has never been observed, and because science is based on observation, evolution cannot be considered scientific.
In fact, examples of speciation have been observed by scientists. We must also remember that we are able to observe just a tiny window of the long history of life on Earth, and the fact that any speciation has been noted at all is impressive indeed.
It’s pretty clear to most of us that life can change over time. For those who aren’t convinced, just take a quick trip to your local animal shelter. Each of the dog breeds there, from the Great Dane to the Chihuahua, descended from a single ancestral population. As you probably already know, that ancestral group was a wolf-like species. "How did these drastic changes take place?" Well, basically, genetic variation within that original population was acted upon by selective forces. Now, just to be clear, the selection at work here wasn’t natural. It was the result of breeding done over hundreds of years. But the basic principle is the same. Genetic variation plus some sort of selection results in genetic change. This is evolution.
For the most part we are ok with accepting this. Yet many people still have a problem with the "Theory of Evolution.' Those suspicious of evolutionary Theory generally split evolution into two categories. Instead of arguing that evolution is completely impossible, they will say something like, “I know microevolution is real, but I just can’t accept macroevolution.”
Kent Hovind, an especially outspoken opponent of evolutionary theory, often makes this argument in his presentations:
“Maybe you’re talking about macroevolution. That’s where an animal changes into a different kind of animal. Nobody’s ever seen that. Nobody’s seen a dog produce a non-dog. I mean you may get a big dog or a little dog, I understand, but you’re going to get a dog, okay?” (source)
But what does this mean? What is the difference between micro and macroevolution anyway, and why is one of them ok while the other is condemned?
Well, like many terms used in the evolution debate, the definitions tend to differ depending on who you talk to. This can make rational discussion difficult. Most opponents of evolution, like Kent Hovind, say that macroevolution refers to one “type” or “kind” of organism evolving into another “kind”. Microevolution, they might say, is evolution within a “kind”. Evolution of one dog breed into another, they would say, is microevolution. Evolution of a “dog into a non-dog”, as Hovind puts it, would be “macroevolution.”’
One big problem with this argument is that “kind” is not clearly defined. It is a subjective term referring to organisms that seem similar to each other. Now, this is a definition that can easily be manipulated. And it doesn’t work very well when asking scientific questions. Because there is disagreement about what they actually mean, the terms micro and macroevolution aren’t often used in scientific literature. But when biologists do refer to “macroevolution”, most define it as “evolution above the species level”.
In other words, at the smallest scale, macroevolution is the development of a new species. This definition is more useful because you can objectively determine whether two organisms are members the same species, but “kind” has no specific definition.
So what does “species” mean anyway? How is it different from “kind?” Well, the term species can be hard to define. Life is complex, and categorizing it into clear groups can be tricky. The currently accepted definition of species comes from what we call the “biological species concept.” Basically, the biological species concept says that a species is made of populations that actually or potentially interbreed in nature.
So, two populations that cannot mate to produce successful offspring are by definition separate species. Now, this definition doesn’t always work. For example, when you have a species that reproduces asexually, finding the boundaries between species can be a little tricky. But in most cases it does a pretty good job. It’s a good way to objectively determine where one species stops and another one begins.
The Biological Species Concept is especially useful when you have two species that look and act very similar. Eastern and Western Meadowlarks are a good example of this. They look almost exactly the same. But they cannot interbreed successfully. Therefore, they are separate species. This definition also helps when we study evolution. Where can we draw the line between microevolution and macroevolution? Well, it’s never easy, but having a working definition of this thing called a species helps out a lot. When enough genetic changes accumulate in a population, eventually it loses the ability to mate with others of its species. Then, by definition, it becomes a new species. In other words, macroevolution has occurred.
As we just discussed, many critics claim that macroevolution can never happen—one species can never cross over to become another one. This statement might sound valid, but a little bit of investigation shows that it is not well supported by evidence. For one thing, the only difference between micro and macroevolution is scope. When enough micro changes accumulate, a population will eventually lose its ability to interbreed with other members of its species. At this point, we say that macroevolution has occurred.
The same processes—random mutation and natural selection—cause both micro and macro evolution. There are no invisible boundaries that prevent organisms from evolving into new species. It just takes time. Usually, the amount of time required for macroevolution to occur is significant—on the order of thousands or millions of years. That’s why you don’t normally see brand new forms of life appear every time you step out your front door. And that’s also why some people think that speciation never happens at all.
But sometimes macroevolution doesn’t take that much time. In fact, the evolution of new species sometimes happens so quickly that we can actually see it take place! Let’s look at a few recent examples.
Biologists Peter and Rosemary Grant had been studying finches since 1973. They lived on an island called Daphne Major in the Galapagos. It was here that they conducted their studies. When they first began their studies, only two species of Finch lived on Daphne Major: the medium ground finch and the cactus finch. But, in 1981, Peter and Rosemary noticed that an odd new finch had immigrated to the island. It was a hybrid, a mix between a cactus finch and a medium ground finch. It didn’t quite fit in with the other birds. The odd misfit had an extra large beak, an unusual hybrid genome, and a new kind of song. But somehow he was still able to find a mate. The female was also a bit of a misfit and had some hybrid chromosomes of her own. So their offspring were very different from the other birds on the island.
Rosemary and Peter continued to carefully watch the odd hybrid line. They wondered if the birds would become isolated from the other finch species on the island or if they would eventually re-assimilate. After four finch generations, a drought killed off many of the birds on Daphne Major. In fact, almost the entire hybrid line was exterminated. Only a brother and sister pair remained. The two family members mated with each other, producing offspring that were even more unique than their parent line. From that point on, as far as biologists Peter and Rosemary could tell, the odd population of finches mated only with each other. They were never seen to breed with the cactus finches or the medium ground finches on the island. The finches with the strange song had become a brand new species.
Another example of speciation, or macroevolution, also took place on an island—this time, on the beautiful Portuguese island of Madeira. According to history books, the Island of Madeira was colonized by the Portuguese about 600 years ago. The colonizers brought with them a few unassuming European House Mice, which they accidentally left on the island. It’s also possible that a group of Portuguese House Mice was dropped off later on.
Recently, Britton-Davidian, an evolutionary biologist at University Montpellier 2 in France, decided to collect samples of the Madeira mice and see how those original populations had changed over time. What she found was surprising. Rather than just one or two species of mouse, she found several. In only a few hundred years, the original populations of Mice had separated into six genetically unique species. The first mouse populations had 40 chromosomes altogether. But the new ones were quite different. Each new variety had its own unique combination of chromosomes, which ranged in number from 22 to 30.
What seems to have happened is that, over time, the mice spread out across the island and split into separate groups. Madeira is a rugged volcanic island with crags and cliffs. So it makes sense that this would have been easy to do. There were many isolated corners for the mice to occupy. Over time, random mutations occurred—some chromosomes became fused together.
Now, In order to reproduce successfully, both parents must have the same number of chromosomes. So when a population develops a chromosome fusion, suddenly that group cannot mate with the other members of its species. It becomes a brand new species. That’s exactly what happened on Madeira. And because of this phenomenon, 6 new species evolved from just 1 or 2 in an extremely short amount of time.
Another fascinating example of macroevolution was recently observed by researchers at Pennsylvania State University. This time, two species combined to make a single new one. In 1997, researchers at Penn State noticed a fruit maggot infestation on some recently introduced Asian Honeysuckle bushes. They decided to investigate the Honeysuckle fly population and determine how it was related to the other flies nearby. When they examined the honeysuckle fly’s genes, the researchers discovered something interesting. The fly appeared to be a hybrid of two native species—the blueberry fly and the snowberry fly.
But the honeysuckle fly’s genetic material was not an exact balance between that of the two parent species. The ratios of DNA varied from fly to fly. This showed the researchers that the honeysuckle flies had been breeding amongst themselves for many generations—probably at least 100. Also, they found that the Honeysuckle Flies were very unlikely to breed with any other species. They bred only on their host Honeysuckle plants. So they weren’t likely to mix with flies that lived on a different host.
According to Dr. Dietmar Schwarz, post-doctoral researcher in entomology, as far as the researchers can tell, “The new species is already reproductively isolated. They seem to be in a niche on the brushy honeysuckle where the parent species cannot compete."
While this kind of speciation—two species hybridizing to create a new one—seems odd, it is a significant mechanism of macroevolution. And it’s especially common in plants. In fact, a new species of weed recently arose this way in Great Britain. In 1991, Richard Abbot, a plant evolutionary biologist from St. Andrews University, noticed an unusual weed growing next to a car park in York. He discovered that the species, an unassuming scruffy weed, was a natural hybrid between the common groundsel and the Oxford ragwort, a plant that was introduced to Britain only 300 years ago. The York Groundsel lives in a different niche, or microenvironment, than either of its parent species. It is able to breed and reproduce, but only with other York Groundsel plants. It cannot successfully reproduce with any other species, including either of its parent plants. Thus, by definition, the York Groundsel is its own new species.
So, as we have seen, macroevolution is an established process. Usually it takes thousands of years to occur, but sometimes we get lucky and catch it in the act. When Kent Hovind said that, “no one has ever seen a dog produce a non-dog” he was technically quite correct. But this statement infers that macroevolution means a drastic and obvious change from one type of organism into another. Those who think this way believe that macroevolution is something like two dogs breeding to suddenly produce a cat, or two guinea pigs mating to produce a mouse.
But this is not how evolution works at all. Over millions of years, a dog-like animal may indeed evolve into a something that looks completely unlike a dog. However, this is not something that we would expect to be able to observe. It just takes too much time. To put the scale of evolution into perspective, consider this. If the average lifespan of a United Stated citizen, 78 years, were a single minute, then single-celled life has been around for nearly 100 years. On this scale, all we get to see is one minute. And even in that time frame we sometimes see new species forming. God’s time is not our time and we tend to forget this. What we do expect to observe is a very slow step-by-step accumulation of tiny genetic changes that eventually result in speciation. And indeed, as we discussed today, this is exactly the sort of evidence revealed in nature.
So, macroevolution is not a “myth” by any means. It is supported by a vast amount of evidence. That evidence includes the fossil record and genetics, as discussed in previous BioLogos podcasts, and, when we get lucky, direct observation of speciation. God, being who God is, could conceivably have created species out of thin air in a single instant. But what if instead God created and sustained the process by which new species are created? Does that make him less powerful or “God-like”? Is it somehow more God’s process if it happened in an instant, than it is if it happened over a long period of time? Presumably even if it happened in an instant, it would still happen by some sort of process—only faster.
God’s time is not our time, and perhaps it’s a good idea for all of us to simply stand back in amazement while God does God’s work in God’s time through God’s process.