Transcript Evolution misconceptions

Evolution
Misconceptions that need to be
addressed….
Why talk about the misconceptions?
• Unfortunately, some people have
misconceptions about what evolution is
and isn’t.
• These need to be addressed BEFORE one
learns about the mechanisms of evolution.
Why are there misconceptions?
• Some are simple misunderstandings.
– They may be ideas that developed during the course
of learning evolution.
– They may be something learned incorrectly in class.
– They may be something misquoted in the media.
• Others are deliberate attempts to interfere with
the teaching of evolution.
Misconception #1
• “Evolution is a theory about the origins of
life.”
Fact:
• Evolution deals mainly with how life
changed after its origin.
• Does science try to investigate
how life originated?
– Yes! But this is not the
central focus of evolution.
Misconception #2
• “Evolution is like a climb up a ladder of
progress; organisms are always getting
better.”
Fact:
• It is true that natural selection weeds out
individuals that are unfit for a particular
situation.
• However, for evolution, “good enough” IS good
enough.
– No organism has to be perfect.
– Some animals change a lot, some not much.
– Change ≠ better; what was “better” a million years
ago might not be “better” now.
Misconception #3
• “Evolution means that life changed ‘by
chance.’ ”
Fact:
• Chance does play a part in evolution, but
there are also non-random evolutionary
mechanisms.
– Random mutations are the ultimate source of
genetic change, however natural selection
(the process by which some organisms/traits
survive and some don’t) is not random.
– Example: Aquatic animals
Misconception #4
• “Natural selection involves organisms
‘trying’ to adapt.”
Fact:
• Natural selection leads to adaptation,
but the process doesn’t involve “trying.”
• Either an individual has genes that are
good enough to survive and reproduce, or
it does not—but it can’t get the right
genes by “trying.”
This does NOT happen…..
Misconception #5
• “Natural selection gives organisms what
they ‘need.’ ”
Fact:
• Natural selection has no intentions or senses; it
cannot sense what a species “needs.”
• If a population happens to have the genetic variation
that allows some individuals to survive a particular
challenge better than others, then those individuals will
have more offspring in the next generation, and the
population will evolve.
• But it will not be granted what it “needs” by natural
selection.
This doesn’t happen either…
Misconception #6
• “Evolution is ‘just’ a theory.”
Fact:
• Scientific theories are explanations that are
based on lines of evidence, enable valid
predictions, and have been tested in many ways.
• In contrast, there is also a popular definition of
theory—a “guess” or “hunch.”
• These conflicting definitions often cause
unnecessary confusion about evolution.
Misconception #7
• “Evolution is a theory in crisis and is
collapsing as scientists lose confidence in
it.”
Fact:
• Scientists do not argue whether evolution
occurred, but how it occurred.
– Did it occur slowly and continuously OR quickly and
abruptly?
• Antievolutionists may hear the debates about
how evolution occurs and misinterpret them as
debates about whether evolution occurs.
Misconception #8
• “Gaps in the fossil record disprove
evolution.”
Fact:
• The fact that some transitional fossils are
not preserved does not disprove
evolution.
– Scientists know that some organisms do not
fossilize well; some do not fossilize at all.
– There should be gaps in the fossil record
according to science.
Some transitional fossils do exist:
• Scientists have found many transitional fossils. For
example, there are fossils of transitional organisms
between modern birds and their theropod dinosaur
ancestors, and between whales and their terrestrial
mammal ancestors.
Misconception #9
• “Evolutionary theory is incomplete and is
currently unable to give a total
explanation of life.”
Fact:
• Evolutionary science is a work in progress. New
discoveries are made and explanations adjusted when
necessary. And in this respect, evolution is just like all
other sciences.
• To date, evolution is the only well-supported explanation
for life’s diversity.
Misconception #10
• “The theory of evolution is flawed, but
scientists won’t admit it.”
Fact:
• Scientists have examined the supposed “flaws” that some
people/groups claim exist in evolutionary theory and have found no
support for these claims.
• These “flaws” are based on misunderstandings of evolutionary
theory or misrepresentations of evidence.
• Scientists continue to refine the theory of evolution, but that doesn’t
mean it is “flawed.”
• Science is a very competitive endeavor and if “flaws” were
discovered, scientists would be more than glad to point them out.
A-typical debate….
Misconception #11
• “Evolution is not science because it is not
observable or testable.”
Fact:
• Evolution is observable and testable.
– The misconception here is that science is limited to
controlled experiments that are conducted in
laboratories by people in white lab coats.
– Actually, much of science is accomplished by
gathering evidence from the real world and inferring
how things work.
– Examples: Astronomers and geologists
Fossils such as Archaeopteryx give us
snapshots of organisms as they adapt and
change over time.
Studying modern organisms such as
elephant seals can reveal specific
examples of evolutionary history and
bolster concepts of evolution.
Artificial selection among guppies can
demonstrate microevolution in the
laboratory.
Laboratory experimentation with fruit
flies demonstrates the power of
genetic mutation.
Misconception #12
• “Evolution leads to immoral behavior. If
children are taught that they are animals,
they will behave like animals.”
Fact:
• Humans are members of the animal kingdom.
We share anatomical and biochemical traits with
other animals, and there are many behaviors
that we share—we care for our young, we form
cooperative groups, etc.
• There are other behaviors that are specific to
particular animals.
– In this sense, humans act like humans, slugs act like
slugs, and squirrels act like squirrels.
Linking immoral or inappropriate behavior to evolution
makes no sense. Morality is not based on what is, but on
what ought to be.
• Not going to happen:
Misconception # 13
• “Evolution and religion are incompatible.”
Fact:
• Religion and science (evolution) are very different things.
• In science, only natural causes are used to explain natural phenomena,
while religion deals with beliefs that are beyond the natural world.
• Since science and religion deal with different realms, there doesn't
need to be a conflict between them.
• The misconception that one always has to choose between science and
religion is incorrect.
– Of course, some religious beliefs explicitly contradict science (e.g., the belief that
the world and all life on it was created in six literal days); however, most religious
groups have no conflict with the theory of evolution or other scientific findings.
So…what’s next?
• Now that we have addressed the
misconceptions, we can get into what
evolution really is.