Transcript Misconceptions about Evolution

Misconceptions about Evolution and
the Mechanisms of Evolution
Misconception 1: “Evolution is a
theory about the origin of life.”
Evolutionary theory deals
mainly with how life changed
after its origin.
 Regardless of how life started,
afterwards it branched and
diversified.
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Evolution mainly studies how life forms branch and diversify
Misconception 2: “Evolution is like a
climb up a ladder of progress;
organisms are always getting better.”
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It is true that natural selection weeds
out individuals that are unfit in a
particular situation, but for evolution,
“good enough” is good enough. No
organism has to be perfect.
For example, many organisms (like
some mosses, protists, fungi, sharks,
and crayfish) have changed little over
great expanses of time.
Other groups may have changed and
diversified a great deal—but that
doesn’t mean they got “better.” After
all, climates change, rivers shift
course, new competitors invade—
and what was “better” a million years
ago, may not be “better” today. What
works “better” in one location might
not work so well in another. Fitness is
linked to environment, not to
progress.
Sometimes changes are not needed to survive. Many species
have changed little over great expanses of time
Misconception 3: “Evolution is like a
climb up a ladder of progress and man is
at the pinnacle of animal evolution”
Aristotle’s vision
of a Great Chain
of Being, above.
We now know
that this idea is
incorrect.
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This statement suggests that human evolved from apes, and
human being the panicle of evolution. Both are incorrect!
Man considers himself superior to other creatures; from years of cultural and religious belief he considers
himself the centre of the universe, the pinnacle and even the purpose of creation; and that all creation
revolves around him; and that other creatures are here merely to serve his purpose and are therefore not
considered as beings in their own right.
Misconception 3.1: Humans evolve
from chimpanzees
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It is important to remember that evolution
dosn’t say Humans evolve from
chimpanzees. Humans and chimpanzees
are evolutionary cousins and share a recent
common ancestor that was neither
chimpanzee nor human.
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Humans are not “higher” or “more
evolved” than other living lineages. Since
our lineages split, humans and
chimpanzees have each evolved traits
unique to their own lineages.
Misconception 4: “Gaps in the fossil
record disprove evolution.”

The fact that some transitional fossils are not preserved does not disprove
evolution. The environmental conditions for forming good fossils are not that
common. So, science actually predicts that for many evolutionary changes
there will be gaps in the record.
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Also, scientists have found many transitional fossils. For example, there are
fossils of transitional organisms between modern birds and their dinosaur
ancestors, and between whales and their terrestrial mammal ancestors.
Misconception 5: Individual organisms
evolve during their lifetimes
Natural selection acts on
individuals
but populations evolve
Misconception 6: “Natural selection
involves organisms ‘trying’ to adapt.”
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Natural selection leads to
adaptation, but the process
doesn’t involve “trying.” Natural
selection involves genetic
variation and selection among
variants present in a population.
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.”
Misconception 7: “Evolution means
that life changed ‘by chance.’ ”
The streamlined shape yellow fin tuna is no accident. A
more streamlined shape allows these fish to move
through the water faster. During their evolution, natural
selection favored the more streamlined tuna and other
aquatic swimmers. eg. Shark, dolphin, penguin
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Evolution is NOT a random
process. The genetic variation
on which natural selection acts
may occur randomly, but
natural selection itself is not
random at all.
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The survival and reproductive
success of an individual is
directly related to the ways its
inherited traits function in the
context of its local environment.
Whether or not an individual
survives and reproduces
depends on whether it has
genes that produce traits that
are well adapted to its
environment.
Misconception 8: “Living organisms
must be the product of careful and
conscious design, so perfectly
formed that they cannot be explained
by the random workings of evolution
alone.”
E.g. The human eye_an intelligent
design?

The human eye is
an organ of great
complexity, both in
structure and
function.
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The proponents of intelligent
design (creationism) assert that
the combination of nerves,
sensory cells, muscles, and lens
tissue in the eye could only have
been "designed" from scratch.
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After all, how could evolution,
acting on one gene at a time,
start with a sightless organism
and produce an eye with so many
independent parts, such as a
retina, which would itself be
useless without a lens, or a lens,
which would be useless without a
retina?
Building an eye: step-by-step criterion can be applied
to building a complex organ like the eye
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We begin with the simplest possible case: a
small animal with a few light-sensitive cells.
We could then ask, at each stage, whether
natural selection would favor the incremental
changes that are shown, knowing that if it
would not, the final structure could not have
evolved, no matter how beneficial.
Starting with the simplest light-sensing
device, a single photoreceptor cell, it is
possible to draw a series of incremental
changes that would lead directly to the
lens-and-retina eye: an increase in cell
number, a change in surface curvature, a
slight increase in transparency.
This incremental process is the real reason
why it is unfair to characterize evolution as
mere chance. Chance plays a role in
presenting random genetic variations. But
natural selection, which is not random,
determines which variations will become
fixed in the species.
Critics might ask what good that first tiny step,
perhaps only five percent of an eye, might be.
As the saying goes, in the land of the blind
the one-eyed man is king. Likewise, in a
population with limited ability to sense light,
every improvement in vision, no matter how
slight, would be favored -- and favored
dramatically -- by natural selection.
Design flaws -
Another way to respond to the theory of intelligent design is
to carefully examine complex biological systems for errors that no intelligent designer
would have committed.
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On the left is the vertebrate eye with
the nerve fibers facing out towards the
light source and on the right is an
octopus eye with the nerve fibers
pointing in towards the brain
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Because intelligent design works from a
clean sheet of paper, it should produce
organisms that have been optimally
designed for the tasks they perform.
Conversely, because evolution is
confined to modifying existing structures,
it should not necessarily produce
perfection. Which is it?
Photoreceptor cells in the retina pass
impulses to a series of interconnecting cells
that eventually pass information to the optic
nerve which leads to the brain. Light passes
through the lens to the retina, and then to the
brain.
An intelligent designer, working with the
components of this wiring, would choose the
orientation that produces the highest degree
of visual quality. No one, for example, would
suggest that the neural connections should
be placed in front of the photoreceptor cells - thus blocking the light from reaching them -rather than behind the retina.
Less-than-perfect vision Incredibly, this is exactly how
the human retina is constructed
some eye features seemed poorly ‘designed’:
1.
2.
3.
4.
The nerve fibers from the retinal rods and
cones extend not inward toward the brain
but outward toward the chamber of the
eye and source of light. They have to
gather into a bundle, the optic nerve,
inside the eye, and exit via a hole in the
retina.
Even though the obstructing layer is
microscopically thin, some light is lost
from having to pass through the layer of
nerve fibers and ganglia and especially
the blood vessels that serve them. The
eye is blind where the optic nerve exits
through its hole.
It would not be if the nerve fibers passed
through the sclera and formed the optic
nerve behind the eye.
This functionally sensible arrangement is
in fact what is found in the eye of a squid
and other mollusks, but our eyes, and
those of all other vertebrates, have the
functionally stupid upside-down
orientation of the retina.
Vulnerable to wear and tear, prone to break down and rendered helpless by
microscopic organisms - the human body is in fact an inefficient evolutionary
bodge-job.
Read more: http://www.dailymail.co.uk/health/article-476607/The-tantalising-design-flaws-bodged-bodies.html#ixzz0p7mS3WuZ
The odd things in nature illustrate best how natural selection works.
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Giant Pandas eat bamboo relatively well despite
the fact that they are bears. They possess a
relatively dexterous hand with an opposable
thumb. This hand would win no prize for design.
In contrast to ours it is very clumsy. It is not
constructed like our hand either.
There are five Panda fingers and a thumb. The
thumb is actually a part of the wrist known as
the radial sesamoid.
Giant Pandas are not good at what they do.
They were designed to do what other bears
normally do. Their hand is not well designed but
it works effectively based on what was available.
Pandas don't process their food well either, why?
Their reproductive success as a whole is not
good. Yet, they survive.
Giant Pandas are examples of how nature juryrigs from available components and does not
necessarily do a "well designed" job either.
"Poor design" is consistent with the predictions
of the scientific theory of evolution by means of
natural selection. This predicts that features that
were evolved for certain uses, are then reused
or co-opted for different uses
Misconception 9: “Evolution is not
science because it is not observable or
testable.”
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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.
Astronomers cannot hold stars in their
hands and geologists cannot go back in
time, but in both cases scientists can
learn a great deal by using multiple
lines of evidence to make valid and
useful inferences about their objects of
study.
The same is true of the study of the
evolutionary history of life on Earth,
and as a matter of fact, many
mechanisms of evolution are studied
through direct experimentation as in
more familiar sciences.
Misconception: 10 “Evolution is ‘just’
a theory.”
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In science, a theory is a rigorously
tested statement of general principles
that explains observable and recorded
aspects of the world. A scientific theory
therefore describes a higher level of
understanding that ties "facts" together.
A scientific theory stands until proven
wrong -- it is never proven correct.
The Darwinian theory of evolution has
withstood the test of time and
thousands of scientific experiments;
nothing has disproved it since Darwin
first proposed it more than 150 years
ago.
Indeed, many scientific advances, in a
range of scientific disciplines including
physics, geology, chemistry, and
molecular biology, have supported,
refined, and expanded evolutionary
theory far beyond anything Darwin
could have imagined.
Misconception: 11 “Most biologists
have rejected ‘Darwinism’ (i.e., no
longer really agree with the ideas put
forth by Darwin and Wallace).”
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Evolution by natural selection
has been demonstrated at
many levels of biological
system and is recognized as
the unifying concept in
Biology.
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Darwin’s idea that evolution generally
proceeds at a slow, deliberate pace has
been modified to include the idea that
evolution can proceed at a relatively
rapid pace under some circumstances.
In this sense, “Darwinism” is
continually being modified.
Thus far, however, there have been no
credible challenges to the basic
Darwinian principles that evolution
proceeds primarily by the mechanism
of natural selection acting upon
variation in populations and that
different species share common
ancestors.
Scientists have not rejected Darwin’s
natural selection, but have improved
and expanded it as more information
has become available. For example, we
now know (although Darwin did not)
that genetic mutations are the source
of variation acted on by natural
selection, but we haven’t rejected
Darwin’s idea of natural selection—
we’ve just added to it.
Misconception: 12 “Evolution
supports the idea that ‘might makes
right’ and rationalizes the oppression
of some people by others.”
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Social Darwinism is the belief that all personal and social problems were
inherited. The proponents of social Darwinism believed poverty and many
other social ills were the result of bad genes. In the 1920s, eugenics
movements were popular in many countries, including the United States and
Germany. Eugenics is the study of human improvement by genetic means.
Many eugenicists saw themselves as visionaries who would one day create a
world free of poverty, and physical and mental illness.
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In the nineteenth and early twentieth
centuries, a philosophy called “Social
Darwinism” arose from a misguided
effort to apply lessons from biological
evolution to society. According to this
view, society should allow the weak
and less fit to fail and die, and that this
is not only good policy, but morally
right. Supposedly, evolution by natural
selection provided support for these
ideas.
Pre-existing prejudices were
rationalized by the notion that
colonized nations, poor people, or
disadvantaged minorities must have
deserved their situations because they
were “less fit” than those who were
better off. This misapplication of
science was used to promote social and
political agendas.
The “science” of Social Darwinism was
refuted. Biological evolution has stood
the test of time, but Social Darwinism
has not.
Misconception: 13 “Evolution and
religion are incompatible.”
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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.
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. In fact,
many religious people, including
theologians, feel that a deeper
understanding of nature actually
enriches their faith. Moreover, in the
scientific community there are
thousands of scientists who are
devoutly religious and also accept
evolution.
Pope John Paul II embraces evolution
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"In a major statement of the Roman Catholic Church's position on the
theory of evolution, Pope John Paul II has proclaimed that the theory
is 'more than just a hypothesis' and that evolution is compatible with
Christian faith: "It is indeed remarkable that this theory has
progressively taken root in the minds of researchers following a
series of discoveries made in different spheres of knowledge', the
pope said in his message Wednesday. 'The convergence, neither
sought nor provoked, of results of studies undertaken independently
from each other constitutes, in itself, a significant argument in favor
of this theory..."
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"If taken literally, the Biblical view of the beginning of life and
Darwin's scientific view would seem irreconcilable. In Genesis, the
creation of the world, and Adam, the first human, took six days.
Evolution's process of genetic mutation and natural selection-the
survival and proliferation of the fittest new species-has taken billions
of years, according to scientists ..."
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"The Pope's message went much further in accepting the theory of
evolution as a valid explanation of the development of life on Earth,
with one major exception: the human soul. 'If the human body has its
origin in living material which preexists it, the spiritual soul is
immediately created by God', the Pope said."