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Misconceptions About Evolution, Part 1

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November 21, 2011 Tags: History of Life

Today's entry was written by the BioLogos Editorial Team. You can read more about what we believe here.

Misconceptions About Evolution, Part 1

The website Understanding Evolution, hosted by The University of California Museum of Paleontology, Berkeley, offers its readers numerous helpful resources regarding the science and history of evolutionary biology. The site’s stated goal is to “help you understand what evolution is, how it works, how it factors into your life, how research in evolutionary biology is performed, and how ideas in this area have changed over time.” Among its resources is a list of popular misconceptions about evolutionary theory. In this two part series, we’d like to highlight some of the site’s most helpful responses to these misconceptions. The full list, and many other wonderful resources, can be found at Understanding Evolution.

Misconceptions about Evolutionary Theory and Process

"Evolution is a theory about the origin of life."

Evolutionary theory does encompass ideas and evidence regarding life's origins (e.g., whether or not it happened near a deep-sea vent, which organic molecules came first, etc.), but this is not the central focus of evolutionary theory. Most of evolutionary biology deals with how life changed after its origin. Regardless of how life started, afterwards it branched and diversified, and most studies of evolution are focused on those processes.

For more, see our questions on "What is Evolution?" and "Isn't the Origin of Life Highly Improbable?".

"Evolution is like a climb up a ladder of progress; organisms are always getting better."

One important mechanism of evolution, natural selection, does result in the evolution of improved abilities to survive and reproduce; however, this does not mean that evolution is progressive — for several reasons. First, natural selection does not produce organisms perfectly suited to their environments. It often allows the survival of individuals with a range of traits — individuals that are "good enough" to survive. Hence, evolutionary change is not always necessary for species to persist. Many taxa (like some mosses, fungi, sharks, opossums, and crayfish) have changed little physically over great expanses of time. Second, there are other mechanisms of evolution that don't cause adaptive change. Mutation, migration and genetic drift may cause populations to evolve in ways that are actually harmful overall or make them less suitable for their environments. For example, the Afrikaner population of South Africa has an unusually high frequency of the gene responsible for Huntington's disease because the gene version drifted to high frequency as the population grew from a small starting population. Finally, the whole idea of "progress" doesn't make sense when it comes to evolution. Climates change, rivers shift course, new competitors invade — and an organism with traits that are beneficial in one situation may be poorly equipped for survival when the environment changes. And even if we focus on a single environment and habitat, the idea of how to measure "progress" is skewed by the perspective of the observer. From a plant's perspective, the best measure of progress might be photosynthetic ability; from a spider's it might be the efficiency of a venom delivery system; from a human's, cognitive ability. It is tempting to see evolution as a grand progressive ladder with Homo sapiens emerging at the top. But evolution produces a tree, not a ladder — and we are just one of many twigs on the tree.

For more, see our questions "What is Evolution?" and "Did Evolution Have to Result in Human Beings?".

"Evolution means that life changed 'by chance.'"

Chance and randomness do factor into evolution and the history of life in many different ways; however, some important mechanisms of evolution are non-random and these make the overall process non-random. For example, consider the process of natural selection, which results in adaptations — features of organisms that appear to suit the environment in which the organisms live (e.g., the fit between a flower and its pollinator, the coordinated response of the immune system to pathogens, and the ability of bats to echolocate). Such amazing adaptations clearly did not come about "by chance." They evolved via a combination of random and non-random processes. The process of mutation, which generates genetic variation, is random, but selection is non-random. Selection favored variants that were better able to survive and reproduce (e.g., to be pollinated, to fend off pathogens, or to navigate in the dark). Over many generations of random mutation and non-random selection, complex adaptations evolved. To say that evolution happens "by chance" ignores half of the picture.

For more see our questions on "What is Evolution?" and "How do randomness and chance align with belief in God’s sovereignty and purpose?".

“Humans are not currently evolving”

Humans are now able to modify our environments with technology. We have invented medical treatments, agricultural practices, and economic structures that significantly alter the challenges to reproduction and survival faced by modern humans. So, for example, because we can now treat diabetes with insulin, the gene versions that contribute to juvenile diabetes are no longer strongly selected against in developed countries. Some have argued that such technological advances mean that we've opted out of the evolutionary game and set ourselves beyond the reach of natural selection — essentially, that we've stopped evolving. However, this is not the case. Humans still face challenges to survival and reproduction, just not the same ones that we did 20,000 years ago. The direction, but not the fact of our evolution has changed. For example, modern humans living in densely populated areas face greater risks of epidemic diseases than did our hunter-gatherer ancestors (who did not come into close contact with so many people on a daily basis) — and this situation favors the spread of gene versions that protect against these diseases.

For more see our question "Did evolution have to result in human beings?".

"Species are distinct natural entities, with a clear definition, that can be easily recognized by anyone."

Many of us are familiar with the biological species concept, which defines a species as a group of individuals that actually or potentially interbreed in nature. That definition of a species might seem cut and dried — and for many organisms (e.g., mammals), it works well — but in many other cases, this definition is difficult to apply. For example, many bacteria reproduce mainly asexually. How can the biological species concept be applied to them? Many plants and some animals form hybrids in nature, even if they largely mate within their own groups. Should groups that occasionally hybridize in selected areas be considered the same species or separate species? The concept of a species is a fuzzy one because humans invented the concept to help get a grasp on the diversity of the natural world. It is difficult to apply because the term species reflects our attempts to give discrete names to different parts of the tree of life — which is not discrete at all, but a continuous web of life, connected from its roots to its leaves.

Misconceptions about Natural Selection and Adaptation

“Natural selection involves organisms trying to adapt”.

Natural selection leads to the adaptation of species over time, but the process does not involve effort, trying, or wanting. Natural selection naturally results from genetic variation in a population and the fact that some of those variants may be able to leave more offspring in the next generation than other variants. That genetic variation is generated by random mutation — a process that is unaffected by what organisms in the population want or what they are "trying" to do. Either an individual has genes that are good enough to survive and reproduce, or it does not; it can't get the right genes by "trying." For example bacteria do not evolve resistance to our antibiotics because they "try" so hard. Instead, resistance evolves because random mutation happens to generate some individuals that are better able to survive the antibiotic, and these individuals can reproduce more than other, leaving behind more resistant bacteria.

“The fittest organisms in a population are those that are strongest, healthiest, fastest, and/or largest.”

In evolutionary terms, fitness has a very different meaning than the everyday meaning of the word. An organism's evolutionary fitness does not indicate its health, but rather its ability to get its genes into the next generation. The more fertile offspring an organism leaves in the next generation, the fitter it is. This doesn't always correlate with strength, speed, or size. For example, a puny male bird with bright tail feathers might leave behind more offspring than a stronger, duller male, and a spindly plant with big seed pods may leave behind more offspring than a larger specimen — meaning that the puny bird and the spindly plant have higher evolutionary fitness than their stronger, larger counterparts.

“Natural selection produces organisms perfectly suited to their environments.”

Natural selection is not all-powerful. There are many reasons that natural selection cannot produce "perfectly-engineered" traits. For example, living things are made up of traits resulting from a complicated set of trade-offs — changing one feature for the better may mean changing another for the worse (e.g., a bird with the "perfect" tail plumage to attract mates maybe be particularly vulnerable to predators because of its long tail). And of course, because organisms have arisen through complex evolutionary histories (not a design process), their future evolution is often constrained by traits they have already evolved. For example, even if it were advantageous for an insect to grow in some way other than molting, this switch simply could not happen because molting is embedded in the genetic makeup of insects at many levels.


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KevinR - #66165

November 22nd 2011

This article is an extremely good example of all the “fudge factors” that makes up evolution.

If you do not know how life started how do you get the ability to say ” however, this does not mean that evolution is progressive” because how are you going to know that it started out as a single cell and then somehow “got” to a human being?

If life started out as a single cell then what do you call the development from that single cell to the incredibly complex organism called a human being? Is that not “progress”?

The author repeatedly uses natural selection [coupled to mutations] as a means of sifting out the unsuitable - but how does natural selection result in the creation of new biological materials, new biological structures, new biological functions as a result of those structures and then most importantly the new information required to USE those materials, structures and functions in a meaningful life-sustaining and enhancing way?

To make this a concrete example, how does natural selection or mutation result in a heavy-limbed dinosaur developing the light-weight high-performance skeletal structures and hyper-efficient breathing apparatus for bird-flight?
Where does the information that is required to create the new bones and tissues come from? How does the brain get to know of the existence of those new things and how does it get to know how to use it’s new-found tail to flare for a landing?
Information is non-material so how does purely material processes generate non-material entities? This is the main problem for evolutionary thought. 
Because of this impossible situation, evolution [from a single ancestor to all of living organisms] itself is impossible.
Citing all kinds of examples of changes in organisms doesn’t breach the chasm. One cannot point to simple changes within a single bacteria or Salamander and make the big jump that those kind of changes will result in amoebas or slugs or snakes or monkeys or anything else other than the same kind of organism. The same applies to dogs and cats where we know there are a huge number of different breeds - but they’re all still the same kind of thing. They haven’t changed into elephants or hippos.

Only when evolutionists can transparently and rigorously explain with thoroughly repeatable
and testable examples how one kind can turn into the other will evolution be anything other than a myth. Right now everything reeks of the emperors clothes.


Dunemeister - #66172

November 22nd 2011

KevinR, although I’m sympathetic to your question, I have to ask, why CAN’T mutation, genetic drift, et al, account for changing reptiles into birds? Does evolution posit that heavy-boned dinosaurs evolved into birds? Or did smaller species of dinosaurs do so? Why COULDN’T the changes required to turn a fully-fledged reptile into what we would recognize as a bird occur over lots of time with incremental changes? Why DOESN’T Archaeopteryx represent a transitional form from lizard to bird?

That said, it would be helpful for me to know how it is that apparently interdependent systems could be produced incrementally. Flight is one example, but I think that’s doable. What’s more striking to me is the woodpecker, which has a modified skeleton, tough bill, strong neck, modifications to the eyelid, a long “wraparound” tongue, and strong claws, all in order to perch on a tree and peck at it to get the juicy grubs under the bark without its eyes popping out or suffering a concussion (I forgot to mention how the skull is adapted to make that possible, but several modifications are required). What’s the evolutionary story of how each of those features were singly developed and retained because they furthered the creature’s chances to do the four Fs? What order were they developed in? Or was there one change to one gene that turned the trick on all these changes? I would be satisfied, if there is not answer available to this puzzle, to hear how another suitably complex set of interdependent features (i.e., the individual features are pretty much useless unless present in combination with all the others) were selected for incrementally.


cfauster - #66174

November 22nd 2011

KevinR asked: Information is non-material so how do purely material processes generate non-material entities?

The latest issue of Perspectives on Science and Christian Faith (the journal of the American Scientific Affiliation) has several articles on that very question.  ASA members and other subscribers can discuss the articles at the following blog: http://www.asa3online.org/PSCF/

One of the articles is by Randy Isaac.  Some (though not all) of the points he makes in his current PSCF article can also be found in his essay here at BioLogos at
http://biologos.org/uploads/projects/isaac_scholarly_essay.pdf

I also recommend Dennis Venema’s essay “Evolution and the Origin of Biological Information” at
http://biologos.org/uploads/projects/venema_origin_information.pdf



cfauster - #66175

November 22nd 2011

Sorry I didn’t link to the two BioLogos essays.  These should work:

http://biologos.org/uploads/projects/isaac_scholarly_essay.pdf

http://biologos.org/uploads/projects/venema_origin_information.pdf


cfauster - #66176

November 22nd 2011

Well, maybe not.  Don’t know why.  Anyway, both are at
http://biologos.org/resources/scholarly-essays


RBH - #66186

November 22nd 2011

Dunemeister wrote

<i>What’s more striking to me is the woodpecker, which has a modified skeleton, tough bill, strong neck, modifications to the eyelid, a long “wraparound” tongue, and strong claws, all in order to perch on a tree and peck at it to get the juicy grubs under the bark without its eyes popping out or suffering a concussion (I forgot to mention how the skull is adapted to make that possible, but several modifications are required).  What’s the evolutionary story of how each of those features were singly developed and retained because they furthered the creature’s chances to do the four Fs? What order were they developed in?</i>

Two points. First, evolution is descent with modification.  Every one of the features Dunemeister mentions is a modified version of phenotypic traits every bird species has.  No new structural genes are required, only incremental modifications of existing gene expression is needed.  Even the behavioral features that woodpeckers evince are found in other birds: I can sit at my window and watch blue jays hammering on oil sunflower seeds with their beaks, the seeds held firmly by their feet.   I watch nuthatches probing the bark.  I watch even chickadees doing some beak hammering on seeds.

Second, the phrases “singly developed and retained” and “order were they developed in” misrepresent the case.  Co-evolution of phenotypic features, where variations among individuals in a sexually reproducing population are thrown together in a range of combinations through generations, enables particularly advantageous incremental <i>combinations</i> to be preserved as and when they provide a reproductive advantage.  Multiple features can co-evolve simultaneously because the sexual mixing of varying traits through time produces combinations of traits with differing consequences for reproductive success in appropriate selective circumstances.


Dunemeister - #66187

November 22nd 2011

RBH,

I don’t take issue with the fact that “every one of the features…is a modified version of…traits every bird species has.” The problem (for me) is that it wouldn’t make sense for the bird to develop the eyelids without the strong neck without the strong claws without the modified brain case without the…. That is, it is difficult to ascertain any reasonable story according to which each of these features could be individually selected for without the whole set.

So your response, that “variations among individuals are thrown together in a range of combinations through generations” doesn’t answer the basic question. How did the whole range of variations come together in a creature that we call the woodpecker? Are you suggesting that the whole woodpecker “package” of phenotypic features was selected for/inherited at the same time? I’m sorry, but I just can’t see how that’s even remotely possible except through divine tinkering. I can imagine that God could/would provide the necessary set of mutations and natural pressures more or less directly and thus produce a woodpecker from nonwoodpecker bird species. He could ensure that all those features would come together in a single species and that species take its place in an ecosystem. Otherwise, I just don’t see how it could be done.


Ashe - #66208

November 23rd 2011

RBH - #66395

December 2nd 2011

Dunemeister asked

“How did the whole range of variations come together in a creature that we call the woodpecker? Are you suggesting that the whole woodpecker “package” of phenotypic features was selected for/inherited at the same time?”

Visualize a population of birds in a selective environment that favors a woodpecker-like suite of traits—say, just two traits for the sake of the example, bill toughness and neck strength. Assume for the sake of the illustration that the traits are independent—that the genetic controls for them are not shared across the traits. Across that population there is variation in each phenotypic trait. Since we’ve assumed they’re independent, any given bird in the population will possess each trait in greater or lesser degree. Across the population at any given time, we will find birds with different combinations of bill toughness and neck strength, some with lower values of both, some with higher values of both, and some with mixed values, high on one trait and low on the other. If combinations of those slight modifications of traits together provide better reproductive success—those birds which through the adventitious combinations of sexual reproduction have both slightly tougher bills and slightly stronger necks—then their offspring will preferentially carry both of those slight modifications and have a reproductive advantage over peers with high values on just one or the other or of neither. As that combination of slightly modified birds (not yet woodpeckers) becomes more common in the population through generations due to the selective advantage, variations around the new values of average bill toughness and average neck strength will occur and combinations on the high side of the variation in the two traits will have still further reproductive advantage. Thus over generations the population moves incrementally to tougher and tougher beaks and stronger and stronger necks. Sometime in that series of incremental changes we humans would look at the population and deem it to be woodpeckers now.

Multiply the number of traits and the same scenario holds: under appropriate selective conditions, the members of the population that are on the selectively advantageous side of the several distributions of the various traits will come to dominate the population, and the variation in each generation is the raw material for selection to move the whole population on all the traits more-or-less simultaneously. Each slight modification in the several traits is selectively advantageous, and over generations the greater reproductive success of individuals who bear combinations of advantageous traits will produce the suite of traits we see now.

Or, read Ashe’s link.


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