Challenge Question: Can you explain (in your own
words) how caterpillars and butterflies came to be, using only evolution
principles such as random mutations, small incremental changes, and
natural selection?
Perry,
The reason your question can't have an exact answer is simple. Unless someone invents a time machine nobody can state with 100% certainty how this happened. In the real world, outside of science fiction, this will never happen. So we rely on what we can learn by observing what we see in the fossil record and what we can see in a lab.
From Scientific American:
https://www.scientificamerican.com/article/insect-metamorphosis-evolution/
Complete metamorphosis likely evolved out of incomplete
metamorphosis. The oldest fossilized insects developed much like modern
ametabolous and hemimetabolous insects—their young looked like adults.
Fossils dating to 280 million years ago, however, record the emergence
of a different developmental process. Around this time, some insects
began to hatch from their eggs not as minuscule adults, but as wormlike
critters with plump bodies and many tiny legs. In Illinois, for example,
paleontologists unearthed a young insect
that looks like a cross between a caterpillar and a cricket, with long
hairs coating its body. It lived in a tropical environment and likely
rummaged through leaf litter for food.
Biologists have not definitively determined how or why some insects began to hatch in a larval form, but Lynn Riddiford and James Truman, formerly of the University of Washington in Seattle, have constructed one of the most comprehensive theories.
They point out that insects that mature through incomplete
metamorphosis pass through a brief stage of life before becoming
nymphs—the pro-nymphal stage, in which insects look and behave
differently from their true nymphal forms. Some insects transition from
pro-nymphs to nymphs while still in the egg; others remain pro-nymphs
for anywhere from mere minutes to a few days after hatching.
Perhaps this pro-nymphal stage, Riddiford and Truman suggest, evolved
into the larval stage of complete metamorphosis. Perhaps 280 million
years ago, through a chance mutation, some pro-nymphs failed to absorb
all the yolk in their eggs, leaving a precious resource unused. In
response to this unfavorable situation, some pro-nymphs gained a new
talent: the ability to actively feed, to slurp up the extra yolk, while
still inside the egg. If such pro-nymphs emerged from their eggs before
they reached the nymphal stage, they would have been able to continue
feeding themselves in the outside world. Over the generations, these
infant insects may have remained in a protracted pro-nymphal stage for
longer and longer periods of time, growing wormier all the while and
specializing in diets that differed from those of their adult
selves—consuming fruits and leaves, rather than nectar or other smaller
insects. Eventually these prepubescent pro-nymphs became full-fledged
larvae that resembled modern caterpillars. In this way, the larval stage
of complete metamorphosis corresponds to the pro-nymphal stage of
incomplete metamorphosis. The pupal stage arose later as a kind of
condensed nymphal phase that catapulted the wriggly larvae into their
sexually active winged adult forms.
Some anatomical, hormonal and genetic evidence supports this evolutionary scenario.
Anatomically, pro-nymphs have a fair amount in common with the larvas
of insects that undergo complete metamorphosis: they both have soft
bodies, lack scaly armor and possess immature nervous systems. A gene
named broad is essential for the pupal stage of complete metamorphosis.
If you knock out this gene, a caterpillar never forms a pupa and fails
to become a butterfly. The same gene is important for molting during the
nymphal stage of incomplete metamorphosis, corroborating the
equivalence of nymph and pupa. Likewise, both pro-nymphs and larvae have
high levels of juvenile hormone, which is known to suppress the development of adult features.
In insects that undergo incomplete metamorphosis, levels of juvenile
hormone dip before the pro-nymph molts into the nymph; in complete
metamorphosis, however, juvenile hormone continues to flood the larva's
body until just before it pupates. The evolution of incomplete
metamorphosis into complete metamorphosis likely involved a genetic
tweak that bathed the embryo in juvenile hormone sooner than usual and
kept levels of the hormone high for an unusually long time.
However metamorphosis evolved, the enormous numbers of metamorphosing
insects on the planet speak for its success as a reproductive strategy.
The primary advantage of complete metamorphosis is eliminating
competition between the young and old. Larval insects and adult insects
occupy very different ecological niches. Whereas caterpillars are busy
gorging themselves on leaves, completely disinterested in reproduction,
butterflies are flitting from flower to flower in search of nectar and
mates. Because larvas and adults do not compete with one another for
space or resources, more of each can coexist relative to species in
which the young and old live in the same places and eat the same things.
Ultimately, the impetus for many of life's astounding transformations
also explains insect metamorphosis: survival.
Now here is one for you to answer.
What kind of God would create parasitic organisims?
https://en.wikipedia.org/wiki/Parasitoid
Like Bed bugs:
Bed bugs are parasitic insects of the cimicid family that feed exclusively on blood. Cimex lectularius, the common bed bug, is the best known as it prefers to feed on human blood.
Or watch these videos and ask yourself, is this the work of a loving creator, or the result of millions of years of evolution? Which is more likely?
https://www.youtube.com/watch?v=Go_LIz7kTok
https://www.youtube.com/watch?v=vMG-LWyNcAs
I look forward to your answers.
