Misconceptions about Evolution

Author: Jim Bindon

Home Page: http://www.as.ua.edu/ant/bindon.htm

Links on Misconceptions about Evolution

The Basics of Evolution
(see my web site on evolution)

New variants of genes are continually being added to populations through the random process of mutation

	The recombination of genes increases the variation initially produced by mutation
	The shuffling of genes during formation of sperm and ova results in an almost infinite variety of possible gene combinations in a population

Because of the particulate nature of inheritance, no loss of variation occurs from one generation to the next

Each generation of each population has an enormous store of genetic variation on which natural selection can act

Selection reduces the genetic variation produced by mutation

The fittest individuals are defined as those who leave the most surviving offspring to mature and reproduce

These individuals thereby contribute the most genes to the next generation, and thus over time their genes become most common in the gene pool of the population

New mutations, new combinations of genes, and constantly changing environments continually produce some individuals that are better adapted than others

	Natural selection favors these individuals and selects out individuals with less fit genotypes
	Gradually, the population evolves through the differential perpetuation of genes of the fittest individuals

If a group of populations should become divided into two or more segments by a geographic barrier, evolution of each new group of populations will continue independently

	Differences between the two groups, including differences in reproductive processes, gradually accumulate
	Reproductive isolating mechanisms become more and more effective over prolonged periods of time
	On secondary contact, the two groups are reproductively isolated and two new species have evolved by the process of geographic speciation

Speciation leads to multiplication and diversification of species into higher groups (genus, order, phylum) that retain clear evolutionary links

Ultimately, all species trace back to the origin of life itself

Misconceptions

"The road to Creationism is paved with bad philosophy. However, the engines that transport us down that road are fueled by bits of science, variously chopped, twisted, crushed, mangled, and blended." Philip Kitcher (1982, p. 82)

Types of Misconceptions

Misinterpretations of evidence

There are no ape-human transitional forms

Misunderstandings about the process and terminology of science

Evolution is ONLY a theory

Misconstructions of the nature and implications of evolution

Evolution is a RANDOM process

Five Major Misconceptions about Evolution

	Evolution has never been observed
	Evolution violates the 2nd law of thermodynamics
	There are no transitional fossils
	Evolution says that life originated and evolution proceeds by random chance
	Evolution is only a theory; it hasn't been proved

Alabama Evolution Disclaimer

A MESSAGE FROM THE ALABAMA STATE BOARD OF EDUCATION
[to be pasted in all biology textbooks]

This textbook discusses evolution, a controversial theory some scientists present as a scientific explanation for the origin of living things, such as plants, animals and humans

Implies there are numbers of reputable, knowledgeable scientists who reject evolution

No one was present when life first appeared an earth. Therefore, any statement about life's origins should be considered as theory, not fact

Misuse of term theory

Lay usage which is closer to hypothesis

Misconception about the nature of scientific inquiry into unobservable phenomena

	No one has ever directly observed the earth rotating about the sun
	Most critics of evolutionary theory accept the heliocentric model of our solar system

Theories, like Newtonian mechanics or evolution by natural selection have observational consequences

Even if we cannot directly observe the phenomena theorized about, we can observe their sequelae

The word "evolution" may refer to many types of change. Evolution describes changes that occur within a species. White moths, for example, may "evolve" into gray moths. This process is microevolution, which can be observed and described as fact.

The moth to which the disclaimer refers is the famous peppered moth, Biston betularia, studied in England

	During the Industrial Revolution when trees went black from pollution, the pale colored version of this moth was eaten by birds because it was conspicuous against the black tree trunks
	The black moths became the majority in industrial areas of England

Better examples would include several case studies of natural selection in man

Sickle cell anemia and other hemoglobin abnormalities as a response to malaria

See my web page about this

Glucose 6 Phosphate Dehydrogenase deficiency as a response to malaria

See my web page about this

Evolution may also refer to the change of one living thing to another, such as reptiles into birds. This process, called macroevolution, has never been observed and should be considered a theory.

There are three problems with this statement:

	Misunderstanding the nature of taxonomy and speciation
	Misusing scientific terms: "just a theory"
	Macroevolution has been observed in many ways

The reptiles that gave rise to birds bear little resemblance to living reptiles

	The first birds bore little resemblance to living birds
	The initial speciation event was probably undetectable at the time

The distinction between micro and macroevolution is exploited by critics

The processes of microevolution are the processes of macroevolution

The only difference is the time scale

Basic mutation and selection are the only processes needed to account for reproductive isolation

Both micro and macroevolution have been observed

Ledyard Stebbins calculated that it would take approximately 20,000 generations for mouse-size animal to become an elephant-size animal under undetectable selection

The house mouse (Mus musculus) measures about 6 in. (15 cm) and weighs under 1 oz (28 grams)

African bull elephants (i) measure up to 13 ft (4 m) high at the shoulder and weigh 6 to 8 tons (5400 to 7200 kg)

Assuming selection pressure so small as to be undetectable from one generation to the next (within the error limits of measurements)

Selection pressure means that in any generation slightly larger than average individuals are slightly more likely to survive for whatever reason, slightly more likely to reproduce

20,000 generations would take between 20,000 and 100,000 years

This time period would be virtually undetectable in the geologic record, but many speciation events would have taken place

Speciation has been observed in plant and animal species in lab and nature

	Laboratory speciation events are routinely rejected by critics who have no trouble with laboratory observation of observable consequences of theories from physics and chemistry
	See the excellent FAQ at TalkOrigins: Observed Instances of speciation

Evolution also refers to the unproven belief that random, undirected forces produced a world of living things.

This is a standard creationist canard

The two most important processes driving evolution are mutation and selection

Mutation is a random process

Alteration of genes is without regard to the fitness of the individual

Selection is a highly directional process, the direction being supplied by the environmental circumstances

There are many unanswered questions about the origin of life which are not mentioned in your textbooks, including:

Why did the major groups of animals suddenly appear in the fossil record (known as the Cambrian Explosion)?

The process of fossilization is an extremely rare event upon death of an organism

Fossilization of organisms without hard body parts has a vanishingly small probability of occurrence

An exceptional case of fossilization of soft tissue is the famous Burgess Shale from the Cambrian Era (between 500 million and 600 million years ago)

The ancestors of these creatures were evolving by the ordinary slow processes of evolution (primarily mutation and selection), but they were evolving before the Cambrian when fossilizing conditions were not very good and many of them did not have skeletons anyway

During the Cambrian there was a very rapid flowering of multicellular life

	At this time a large number of the great animal phyla evolved
	Their divergence during a period of about 10 million years is very fast, but not all that fast
	Modern phyla may well have their most recent common ancestors way back in the late Precambrian (1 billion - 600 million years ago)

Why have no new major groups of living things appeared in the fossil record in a long time?

Major groups would be divisions of each living kingdom called phyla (sing. Phylum)

Examples of animal phyla

	Mollusks, which includes snails and shellfish
	Echinoderms, which are starfish, sea urchins
	Chordates, which are animals with spinal cords, including ourselves
	Arthropods which include insects and crustaceans

Major groups evolve gradually through the accumulation of many speciation events

As Dawkins suggests

Think of an oak tree with huge limbs at the base and smaller and smaller branches toward the outer layers where finally there are just lots and lots of little twigs. The little tiny twigs appeared most recently. The larger boughs appeared a long time ago and when they did appear, they were little twigs. If a person said, "Isn't it funny that no major branches have appeared on this tree in recent years, only small twigs?" you'd say the person was stupid

Why do major groups of plants and animals have no transitional forms in the fossil record?

This is simply a false assertion that has no basis in fact

	See the excellent FAQ at TalkOrigins: Transitional Forms
	Most groups do have clear transitional forms although they may not look the way creationists want them to look

How did you and all living things come to possess such a complete and complex set of "instructions" for building a living body?

The set of instructions is our DNA

We got it from our parents and they got it from their parents going back through the generations for some 4 billion years to a tiny bacterium who lived in the sea and was the ancestor of us all

Study hard and keep an open mind. Someday you may contribute to the theories of how living things appeared on earth.

Too bad the the disclaimer’s authors didn’t study hard and keep an open mind

They might have made to contribution to knowledge instead of impeding it

Update since 2/99:

August, 1999: Kansas Board of Education votes to delete any mention of evolution from the state’s science curriculum

October, 1999: It becomes known that the Illinois Board of Education quietly eliminated the term evolution from the state school standards adopted in 1997

November, 1999: The Oklahoma State Textbook Committee voted Nov. 5 to require that new science textbooks used in public schools carry a statement that evolution is a controversial, unproven theory

February 3, 2000: Attorney General ruled that the Oklahoma State Textbook Committee had overstepped its bounds in trying to dictate the content of textbooks and threw out the disclaimer

Selected References

	Darwin, C. 1872 On the Origin of Species by Means of Natural Selection, or The Preservation of "Favoured Races in the Struggle for Life. 6th Edition. London: Murray
	Kitcher, P. 1982 Abusing Science: The Case Against Creationism. Cambridge, MA: MIT Press
	Mayr, E. 1963 Animal Species and Evolution. Cambridge, MA: Belknap Press
	Price, P.W. 1996 Biological Evolution. Philadelphia: Saunders
	Relethford, J.H. 1997 The Human Species: An Introduction to Biological Anthropology. Third Edition. Mountain View, CA: Mayfield Press