A Darwinian Puzzle Solved, Say Researchers
Scientists have pondered questions concerning
the art of mimicry in animals.
Summary: Mimicry is a characteristic common among plants as well as
animals such as snakes, spiders and butterflies. It is the trait of a
harmless creature in which it looks so much like a dangerous one that
predators are scared off. For instance, a harmless hoverfly can look so
similar to a wasp that birds avoid trying to eat it.
"Mimicry of harmless species pretending to be dangerous ones in order
to avoid being eaten is one of the best celebrated examples of the
outcome of evolution by natural selection," says Professor Tom Sherratt,
of Carleton U. in Ottawa, who led the research into a Darwinian question
concerning mimicry — why are some animals better mimics than others
and yet the poorer mimics still manage to survive?
A simple interpretation of Darwin’s theory of natural selection implies all
mimics should closely resemble the species they are trying to
impersonate. One possible explanation for why not all species are good
mimics is that mimicking species may do a poor job in human eyes, but
they may be good enough to fool their predators whose senses are
different from ours. Another explanation is that the poorer mimics may
be an amalgamation of unappetizing species which would be enough to
repel potential predators.
The Canadian scientists involved in the research have another answer.
Larger animals, they say, need to be better at their mimicry because
they make more substantial meals for predators. Smaller prey do not
need such a great performance at mimicking.
Harmless hoverflies, for instance, may look and sound like wasps.
According to Darwinian selection, those that look and sound the most
like wasps would be selected by natural selection to dominate while the
poorer mimics would all be eaten and die out. In a study, the
researchers showed people photos of various species of hoverflies and
asked them to grade how closely each species was to the bee or wasp
it was trying to mimic. The scientists found that the larger the hoverfly
species, the closer it was to the wasp or bee in appearance. A smaller
hoverfly, they determined, only had to vaguely look like a wasp to avoid
becoming a meal because birds would be less interested in them due to
their smaller size.
(Photo of a hoverfly from Wikipedia.)
To read the entire article, click on BBC NEWS.
Comment: This article makes it seem as if animals have the mental
ability to change their appearance. Just look at some of the phrases…”
(Mimicry) is a clever trick if you can pull it off,” “many insects try
(mimicry),” "Mimicry of harmless species pretending to be dangerous
Of course, the writer was thinking in terms of natural selection, but does
natural selection have the power to do as much as it is given credit for
in this story? Mimicry could conceivably happen by accident once or
twice, but there are so many examples of it in the natural world, people
may find the natural selection theory for mimicry is a bit difficult to
Natural selection has been documented in the famous case of the
peppered moths in England in which the moths that more closely
blended in with the tree trunks on which they rested were more likely to
survive predator birds. Yet, natural selection did not create either the
light-colored or the dark-colored peppered moths. Both kinds existed
before dark-colored moths began to dominate over light-colored moths
due to the effects of the Industrial Revolution.
I believe it is much easier to believe that the animals which make use of
mimicry are given this gift by the One who designed them. Creatures that
weren’t given this gift are given other gifts instead that help them survive
equally as well, such as speed (gazelles), strength (elephants), an odor
(skunks), camouflage (snowshoe rabbits), etc.
The best survival gift that we humans have been given is the gift of a
superior mind. However, no amount of human wisdom can ensure that
we will live forever. For that assurance we must turn to a wisdom that far
exceeds our own — the wisdom of our Creator (Romans 11:33). No
human mind could have dreamed up the path of salvation and eternal
life which the Bible presents to us — God sacrificing His innocent and
divine Son on a cross so that the Son of God could pay for our sins
and so that we could enjoy eternal life in heaven. Let’s not be so foolish
as to turn down this free gift available to everyone through faith in Jesus
Christ as our Savior.
“God made him who had no sin to be sin for us, so that in him we might
become the righteousness of God” (2 Corinthians 5:21).
LSI Blog - Wednesday, March 28, 2012