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Science
Jellyfish: “wonders in the
deep”
David Burges
Picture: Wikimedia Commons/sami73
The typical way many of us encounter jellyfish.
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From an illustration by Matthias Jacob Schleiden (1804-1881)
F
ROM AMONG the Creator’s “wonders in the
deep” (Ps. 107:24), most of us will at some
time have seen jellyfish, either floating in
the sea or washed up on the beach as apparently formless circles of translucent jelly.1 They
seem to have no recognisable organs and to be
as simple a life-form as one could imagine. And
yet recent scientific research has been revealing
surprising levels of complexity in the structure
and behaviour of jellyfish, which speak to us of
Divine handiwork.
There are thousands of species, found in all
parts of the world, and evolutionists claim that
they are among the oldest creatures on earth,
pre-dating bony fish, insects and dinosaurs.
They are found in open oceans, along coasts and
in lagoons, and a few can live in fresh water.
They can survive in oxygen-depleted and polluted waters, which may explain why they are
flourishing in many areas where fish stocks are
severely depleted through pollution, over-fishing
and rising sea temperatures.2 Jellyfish ‘blooms’
consisting of many thousands of individuals have
become more common in recent years.
Jellyfish reproduce sexually, the males and
females releasing sperm and eggs into the open
sea for fertilisation.3 The fertilised egg grows
into a larval stage, which attaches itself to a
solid surface and develops into a polyp, having a small stalk with a mouth surrounded by
Stages of jellyfish life-cycle.
upward-facing tentacles, like a miniature of the
closely related sea anemones and corals. After a
period of growth the polyp buds and produces
many tiny jellyfish, which swim away and grow
by feeding on plankton. Adults range in size from
the Australian Irukandji, which is about the size
of a fingernail, to the lion’s mane jellyfish with a
bell eight to ten feet wide and tentacles trailing
100 or more feet behind it.
All jellyfish are carnivorous, feeding on plankton, crustaceans, fish eggs, small fish and other
jellyfish, using their tentacles as drift nets. Many
have stinging cells in their tentacles, which respond to the pressure of potential prey brushing
against them by releasing tiny harpoons packed
1. Because they are invertebrates and not fish, they are
usually referred to in North America as ‘jellies’ or ‘sea
jellies.’
2. With these trends, jellyfish may have to replace fish as
part of our diet! Around twelve species are currently
harvested and processed for human consumption,
mainly in south-east Asia; Wikipedia article: “Jelly­
fish.”
3. Ibid.
The Testimony, July 2011
with chemical neurotoxins. In this way they can
paralyse or kill their prey before it can damage
the jellyfish’s delicate tissues. Consequently it is
advisable to avoid contact with jellyfish because
some species can produce painful stings or even
death.
A complex visual system
Jellyfish have generally been considered to have
no brain or central nervous system, and to have
only light-sensitive patches for distinguishing
light and dark; but new research has shown that
this is not the case, and that their sensory organs
are far more complex than had been thought. For
example, scientists have recently discovered that
the box jellyfish that inhabits mangrove swamps
has an astonishing visual system comprising an
interactive matrix of twenty-four eyes of four distinct types, two of them very similar to our own
eyes, which they use to navigate through the maze
of mangrove roots.4 These eyes are equipped with
a cornea, lens and retina, as human eyes are, but
they are also suspended on stalks with heavy
crystals on one end that act as weights, ensuring
that the eyes are focused unerringly skyward. At
night the jellyfish move away from the trees and
sink to the muddy bottom of the open lagoon. In
the morning they rise again toward the surface,
and their upturned eyes scan the sky until they
spy the mangrove canopy, where they return to
feed among the trees.
Detailed investigation of the architecture of
the nerve pathways in jellyfish has revealed areas
where many nerve cells come together to form
centres where sensory information is processed
to produce appropriate actions, very much like
miniature brains. One researcher even maintains
that jellyfish can be said to possess a brain. He
has spent years studying the resident population
of moon jellyfish in Roscoe Bay, British Columbia,
starting with the basic question, How can there
even be a resident population? If, like plankton,
they simply drift with the tides, they should be
flushed out to the open sea.
He discovered that, when the tide starts flowing out, they dive down to find still water near
gravel bars, and wait there until the tide returns,
when they rise again and return to the bay. He
also learned that jellyfish are able to measure the
salinity of the water, and, when fresh water flows
into the bay in the summer snowmelt, they dive to
find the denser, salty water beneath. Furthermore,
they commonly gather together in schools, and
are able to distinguish their own species from
The Testimony, July 2011
All pictures Wikimedia Commons
Group of moon jellyfish.
Malene Thyssen, http://commons.wikimedia.org/wiki/User:Malene
other, possibly predatory, species of jellyfish, using chemical receptors on their upper surfaces.
Many species of jellyfish are able to shine in
the darkness of the deep by producing fluorescent
proteins, a phenomenon known as bioluminescence. Scientists have been able to clone the gene
responsible for their production and use it to
produce fluorescent markers for genes inserted
into other cells or organisms for genetic research,
earning several biochemists a Nobel Prize.
Bioluminescence is widespread among marine
creatures and so is considered commonplace, yet
it seems incredible that genes to produce such
complex biochemicals could arise purely by
chance mutations, when it takes some of the best
brains in science even to find out how they work!
Intelligent design
All of this implies that jellyfish possess a level
of ‘intelligence’ and awareness of their environment far greater than may have been imagined. It
seems remarkable that such levels of complexity
should be found in creatures so ‘primitive’ and
supposed to have evolved at such an early stage in
earth’s history. Jellyfish join a long list of supposedly ‘simple’ organisms which have been shown
by detailed research to be anything but simple,
and display all the hallmarks of intelligent design by the all-wise Creator. They certainly rank
high among the “innumerable teeming things”
that inhabit the “great and wide sea,” which are
among the manifold works of the LORD that He
has made in His wisdom (Ps. 104:24,25, NKJV).
4. Natalie Ainger, “So much more than plasma or poison,”
New York Times, Online Science, 6 Jun. 2011, citing
work published in the Journal of Current Biology, 10
May 2011.
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