authorbio
A worldrenowned
scientist,
Douglas
Futuyma is
professor of
evolutionary
biology at the
State
University of
New York at
Stony Brook...
article highlights
Natural selection is a very efficient, predictable mechanism of evolution,
illustrating:
 how species adapt to their environment
 the reproductive success of a species
 design in nature
 evidence of evolution in action, e.g., antibiotic resistance
December 2004
Natural Selection: How Evolution Works
evolution: evolution in action
Natural Selection: How Evolution Works
Interview with Douglas Futuyma
An ActionBioscience.org original interview
Interview with Douglas Futuyma
ActionBioscience.org: What is natural selection, and how is it
central to the theory of evolution?
Natural
selection is
how species
evolve by
adapting to
their
environment.
Futuyma: Natural selection is the process by which species adapt to
their environment. Natural selection leads to evolutionary change when
individuals with certain characteristics have a greater survival or
reproductive rate than other individuals in a population and pass on
these inheritable genetic characteristics to their offspring. Simply put,
natural selection is a consistent difference in survival and reproduction
between different genotypes, or even different genes, in what we could
call reproductive success. [A genotype is a group of organisms sharing
a specific genetic makeup.]
Natural
selection
explains design
in nature.
The reason that natural selection is important is that it’s the central
idea, stemming from Charles Darwin and Alfred Russel Wallace, that
explains design in nature. It is the one process that is responsible for
the evolution of adaptations of organisms to their environment.
Darwin’s book On the Origin of Species by Means of Natural Selection
caused quite a stir when it appeared in 1859. Evidence to support
evolution and natural selection, of course, has accumulated over time,
and now science accepts that evolution is a fact and that natural
selection explains very well how adaptive evolution takes place.
ActionBioscience.org: Is natural selection the only mechanism
of evolution?
Evolution has
several
mechanisms.
Futuyma: No, certainly not. There cannot be evolution without genetic
variation in the first place. So there must be mutation and often
recombination to generate the different genotypes or the different
versions of the genes, known as alleles, which then may or may not
make a difference in the ability of an organism to survive and
reproduce. You can’t have any evolutionary change whatever without
mutation, and perhaps recombination, giving rise to genetic variation.
But once you have genetic variation, there are basically two major
possibilities:
Genetic drift
involves
random
changes.


Natural
selection is
more
consistent,
adaptive
change.
First, there is simply no difference between the different
genotypes or different genes in their impact on survival or
reproduction, and in that case, you can have random changes of
one versus the other type in a population or a species until
eventually one replaces the other. That is an evolutionary
change. It happens entirely by chance, by random fluctuations.
That is what we call the process of genetic drift.
Genetic drift is very different from possibility number two,
natural selection, which is a much more consistent, predictable,
dependable change in the proportion of one gene vs. another,
one genotype vs. another. Why? Simply because there is some
consistent superiority, shall we way, of one genotype vs.
another in some feature that affects its survival or some feature
affecting its reproductive capabilities.
ActionBioscience.org: Does natural selection lead to new
species, and if so, how?
Futuyma: It sometimes does but not always. A great deal of evolution
by natural selection can happen without the formation of new species.
Natural selection is only the process of adaptation within species, and
Natural
we see many examples of that. Under some circumstances natural
selection plays
selection does play a role in the origin of new species, by which I mean
a role in the
a splitting of one species lineage into two different lineages that do not
origin of new
interbreed with one another -- for example, the splitting of one
species.
ancestral primate lineage into one that became today’s chimpanzee and
the other that became the hominid line resulting in our own species.
The process of splitting and becoming reproductively isolated, that is,
incapable of breeding with one another, can often involve natural
selection but perhaps not always.
ActionBioscience.org: Some take natural selection to mean
survival of the fittest. How does this slogan sometimes lead to
misconceptions?
Futuyma: “Survival of the fittest” is a slogan that is really very
misleading. First of all, it’s not an adequate description of what really
goes on in nature for two reasons:

“Survival of the
fittest” is a
misleading
term.

Sometimes there isn’t a “fittest” type. There may be several
different types that are equally fit for different reasons. Perhaps
they’re adapted to different facets of the environment. One is
not going to replace the other because each has its proper place
in the environment.
Moreover, it’s not just a matter of survival. Natural selection is a
difference in reproductive success that involves both the ability
to survive until reproductive age and then the capacity to
reproduce.
The notion of the survival of the fittest is also unfortunate because it
has been viewed as a kind of tautology, a kind of empty statement for
those who say that the fittest are those that survive and so there’s no
real predictive content to the notion of natural selection. That is simply
false.
ActionBioscience.org: How do scientists interpret “chance,” and
does it play a role in natural selection?
Evolution
involves
unpredictable
chance.
Natural
selection
provides
predictability.
Futuyma: Philosophers and scientists use “chance” only in the sense of
unpredictability. Chance means essentially that you cannot predict the
outcome of a particular event. For example, you cannot predict whether
your next child will be a son or a daughter, even though you can
specify the probability or likelihood. “Chance” does not mean lack of
purpose or goal in science. If it did, we could say that absolutely
everything in the natural world is by chance because we don’t see any
purpose or goal in storms, in ocean currents, or anything else.
Evolution certainly does involve randomness; it does involve
unpredictable chance. For example, the origin of new genetic variation
by mutation is a process that involves a great deal of chance. Genetic
drift, the process I referred to earlier, is a matter of chance.
However, natural selection itself is the single process in evolution that
is the antithesis of chance. It is predictable. It says that, within a
specific environmental context, one genotype will be better than
another genotype in survival or reproduction for certain reasons having
to do with the way its particular features relate to the environment or
relate to other organisms within the population. That provides
predictability and consistency. So, if you have different populations with
the same opportunity for evolution, you would get the same outcome.
ActionBioscience.org: Can natural selection select for future
needs of a species?
Natural
selection
cannot prepare
species for
future needs.
Futuyma: No, because natural selection is not like Mother Nature
watching over us. Since natural selection is totally an impersonal
process that is nothing more than a difference, generation by
generation, in the reproductive success of one genome over another,
there’s no way that it can look forward to the future or guard against
the possibility of extinction. What individuals have right now that gives
them superior adaptation may lead to disaster tomorrow.
ActionBioscience.org: Could you give us an example of natural
selection at work in the recent past?
The apple
maggot fly
Futuyma: There are so many examples of that! One example is the
apple maggot fly. About 100 years ago it started to become a serious
evolved in
response to
change in
available food.
pest of apple orchards in New England and New York State. It’s now a
threat throughout most of northern United States. It originally fed just
on hawthorn fruits, but then it adapted to apple and it’s become a
serious threat to the industry. That is a genetic change propagated by
natural selection.
Resistance to
pesticides is
due to adaptive
change.
Perhaps much more crucial is an issue that agriculture has to deal with
all the time: the evolution in hundreds of species of insects of
resistance to various chemical insecticides. The insects then become
more and more difficult to control.
Closer to home, and more serious, is the single greatest crisis in
Antibiotic
resistance also medicine: antibiotic resistance. The fact is that enormous numbers of
the most dangerous bacteria and viruses have evolved to be resistant
illustrates
to the antibiotics or other drugs that used to be effective against them.
natural
An obvious example is the HIV virus, which, as we know, is capable of
selection.
rapidly evolving resistance to drugs that once were effective against it.
ActionBioscience.org: The late Stephen Jay Gould has written
that if we were to rewind the “tape” of evolutionary history and
play it again, the results would not be the same [S.J.Gould,
Wonderful Life, 1989]. Why?
Futuyma: Well, it almost certainly would not be the same. I don’t think
anyone can say how different it would be, whether it would be along
the same general lines or utterly, unimaginably different.
Evolutionary
history could
not happen the
same way
again.
Environmental
circumstances
cannot be
repeated.
Natural
selection
makes the
“argument
from design”
superfluous.
Of course, it wouldn’t be the same, because first of all, random
processes are involved in the evolutionary process. For example, the
origin of new mutations: a lot of evolution is dependent on particular
mutational changes in genes that were very, very rare or unlikely, but
that just happened at the right time, in the right species, in the right
environment, but it need not happen that way. So, there’s this
unpredictability.
In addition, the particular sequence of environmental changes that the
Earth underwent and that organisms were exposed to over billions of
years has left a long-term imprint on species as they are today. If the
sequence of environmental changes were different, you would have a
different evolutionary history, leading to entirely different organisms
over time.
ActionBioscience.org: Why does natural selection pose a threat
philosophically to some people?
Futuyma: The philosopher Daniel Dennett called natural selection
“Darwin’s dangerous idea” for a good reason: it is a very simple natural
mechanism that explains the appearance of design in living things.
Before Darwin, the adaptations and exquisite complexity of organisms
were ascribed to creation by an omnipotent, beneficent designer,
namely God, and indeed were among the major arguments for the
existence of such a designer. Darwin’s (and Wallace’s) concept of
natural selection made this “argument from design” completely
superfluous. It accomplished for biology what Newton and his
successors had accomplished in physics: it provided a purely natural
explanation for order and the appearance of design. It made the
features of organisms explicable by processes that can be studied by
science instead of ascribing them to miracles. The contemporary
“intelligent design” movement is simply a repetition of the predarwinian
argument, and of course it cannot be taken seriously as a scientific
explanation of the properties of living things.
© 2004, American Institute of Biological Sciences. Educators have permission to
reprint articles for classroom use; other users, please contact editor for reprint
permission. See reprint policy.
About the author: A world-renowned scientist, Douglas Futuyma
is professor of evolutionary biology at the State University of
New York at Stony Brook. He has been president of the Society
for the Study of Evolution and the American Society of
Naturalists. He was the editor of Evolution and Annual Review
of Ecology and Systematics. Futuyma received the Sewall
Wright Award from the American Society of Naturalists, has
been a Guggenheim Fellow, and was a Fulbright Fellow in
Australia. Along with his many scientific publications, he is the
author of Evolutionary Biology (3rd ed., 1998, Sinauer Assoc.), a
textbook widely used in undergraduate- and graduate-level
biology courses. Dr. Futuyma is also the author of Science on
Trial: The Case for Evolution (1995, Sinauer Assoc.), an
introduction to the creation–evolution controversy from the
perspective of a scientist. His new textbook, Evolution (Sinauer
Assoc.), will be published early in 2005. Futuyma received his
B.S. at Cornell University and his M.S. and Ph.D. (1969) in the
Department of Zoology of the University of Michigan, where he
studied with Lawrence Slobodkin. Futuyma was interviewed at
the AIBS Symposium "Evolutionary Science and Society:
Educating a New Generation" at the 2004 NABT convention.
http://life.bio.sunysb.edu/ee/futuyma.html
Natural Selection: How Evolution Works
learnmore links
“Hypotheses, Facts, and the Nature of Science”
Read an excerpt from Douglas Futuyma’s textbook, Evolutionary Biology, 3rd ed., Sinauer
Associates, 1998, pp. 9–12.
http://www.stephenjaygould.org/library/futuyma_theory.html
Darwin and natural selection
See a synopsis of how Darwin arrived at the natural selection hypothesis.
http://anthro.palomar.edu/evolve/evolve_2.htm
Natural selection tutorial
Natural selection explained succinctly. Click on “Natural Selection in Practice” at the bottom
of the page to read about examples of natural selection in action.
http://www.biology-online.org/2/10_natural_selection.htm
Natural selection at the gene level
An illustrated description of how natural selection works, using sickle-cell traits and AIDS as
examples.
http://anthro.palomar.edu/synthetic/synth_7.htm
Evolution 101
The “Understanding Evolution” website provides a tutorial about the basics of evolution,
including mechanisms for how evolution works.
http://evolution.berkeley.edu/evosite/evo101/index.shtml
Darwin online
The Origin of Species: By Means of Natural Selection or the Preservation of Favored Races in
the Struggle for Life, Charles Darwin’s classic, published in 1859, is the monumental work
that influenced the theory of evolution (1993 reissue, Modern Library). Read it in its entirety
online:
http://www.literature.org/authors/darwin-charles/the-origin-of-species
Read a book
Science on Trial: The Case for Evolution, by Douglas Futuyma, examines the failings of the
scientific creationists and explains the theory and facts of evolution in a clear and readable
fashion. Sinauer Associates, 1995 (out of print, but may be available at your local library).
getinvolved links
EvoTutor
Interactive simulations make learning about evolution enjoyable, created by a doctoral
student of evolution, ecology, and behavior at the University of Austin, TX. Requires special
applications.
http://www.evotutor.org
For undergraduate educators: evolution models
Natural selection and genetic drift modeling exercise.
http://www.wcer.wisc.edu/ncisla/muse/naturalselection/index.html
http://darwin.eeb.uconn.edu/simulations/selection.html
http://darwin.eeb.uconn.edu/simulations/jdk1.0/drift.html
http://www.biology.arizona.edu/evolution/act/drift/about.html
http://www.nyu.edu/projects/fitch/resources/PopGen2/
For middle- and high-school educators: natural selection lessons
» Natural Selection Model
http://www.shodor.org/cserd/Resources/Activities/NaturalSelection/
» Evolution Lab
http://www.biologyinmotion.com/evol/index.html
» PBS: Sex and the single guppy
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson4/act2.html
» PBS: The mating game...
http://www.pbs.org/wgbh/evolution/sex/mating/
» Nowhere to Hide
http://www.sciencenetlinks.com/Esheet.cfm?DocID=80
» The Nature and Nurture Walk
http://www.ology.amnh.org/genetics/naturewalk/pages/naturenurtureGame.html
» Natural Selection: A Cumulative Process
http://www.indiana.edu/~ensiweb/lessons/ns.cum.l.html
» The Natural Selection of Stick-Worms
http://www.indiana.edu/~ensiweb/lessons/ns.st.wm.html
» The Natural Selection of Bean Hunters
http://www.indiana.edu/~ensiweb/lessons/ns.beans.html
» The Chips Are Down: A Natural Selection Simulation
http://www.indiana.edu/~ensiweb/lessons/ns.chips.html
» Bebbledwark World
http://www.fresno.k12.ca.us/schools/S090/_atkinsgatebio/BebbleHTML/bebbletitlepage.htm
» When Milk Makes You Sick
http://www.indiana.edu/~ensiweb/lessons/tp.milk3.html
educatorresources
ActionBioscience.org original lesson
This lesson has been written by a science educator to specifically accompany the above
article. It includes article content and extension questions, as well as activity handouts for
different grade levels.
Lesson Title: Natural Selection
Levels: high school - undergraduate
Summary: Students develop a conversation with Darwin, chart examples of natural
selection in action, speculate on the future of evolutionary history…and more!
Download/view lesson, click icon:
(To open the lesson's PDF file, you need Adobe Acrobat Reader free software.)
Useful links for educators
» Natural Selection and Darwin’s Finches
Prentice-Hall provides a book chapter with an overview and suggestions for class activities.
http://wps.prenhall.com/esm_freeman_evol_3/0,8018,849374-,00.html
» The Beaks of the Finches
This classroom activity is published by Access Excellence.
http://www.accessexcellence.org/AE/AEC/AEF/1996/sprague_beaks.html
» For undergraduate educators: evolution models
http://www.wcer.wisc.edu/ncisla/muse/naturalselection/index.html
http://darwin.eeb.uconn.edu/simulations/selection.html
http://darwin.eeb.uconn.edu/simulations/jdk1.0/drift.html
http://www.biology.arizona.edu/evolution/act/drift/about.html
http://www.nyu.edu/projects/fitch/resources/PopGen2/
» For middle- and high-school educators: natural selection activities
http://www.shodor.org/refdesk/Resources/Activities/NaturalSelection/
http://www.biologyinmotion.com/evol/index.html
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson4/act2.html
http://www.pbs.org/wgbh/evolution/sex/mating/
http://www.sciencenetlinks.com/Esheet.cfm?DocID=80
http://www.ology.amnh.org/genetics/naturewalk/pages/naturenurtureGame.html
http://www.indiana.edu/~ensiweb/lessons/ns.cum.l.html
http://www.indiana.edu/~ensiweb/lessons/ns.st.wm.html
http://www.indiana.edu/~ensiweb/lessons/ns.beans.html
http://www.fresno.k12.ca.us/schools/S090/_atkinsgatebio/BebbleHTML/bebbletitlepage.htm
» Assessment resources
http://www2.acs.ncsu.edu/UPA/assmt/resource.htm
http://www.moesc.k12.oh.us/assess-resources.htm
http://www2.gsu.edu/~mstnrhx/457/rubric.htm
» Rubrics, ideas and worksheets for preparing presentations
http://www.uwstout.edu/soe/profdev/rubrics.shtml
Useful links for student research
Refer also to the “learn more” and “get involved” links above.
» The Problem of Antibiotic Resistance fact sheet
http://www.niaid.nih.gov/factsheets/antimicro.htm
» Types of antibiotics
http://www.surgeryencyclopedia.com/A-Ce/Antibiotics.html
» Biographies of Charles Darwin
http://www.online-literature.com/darwin/
http://en.wikipedia.org/wiki/Charles_Darwin
» The modern synthesis of the theory of evolution
The 19th century ideas of Darwin and Wallace and 20th century discoveries
http://www.talkorigins.org/faqs/modern-synthesis.html
» Evo-devo, the new evolutionary synthesis
http://en.wikipedia.org/wiki/Evolutionary_developmental_biology
» Sexual selection in humans
http://www.thegreatdebate.org.uk/sexualselection.html
» Will evolution continue?
A discussion of human evolution with five future scenarios can be found under the title Fast
Forward: The Future of Human Evolution
http://www.msnbc.msn.com/id/7103668/
» A World Without Elephants?
This includes thoughts on the future of evolution with Harvard paleontologist Andy Knoll,
with video and text answers to questions.
http://nai.arc.nasa.gov/video_archive/andy_knoll.cfm
» Millennium Ecosystem Assessment’s future scenarios
http://www.millenniumassessment.org/en/Products.Global.Scenarios.aspx