B. Sc. (Hons.), Ph.D., F. M.
Dr Sarfati’s Ph.D. in physical chemistry is from
Victoria University, Wellington, NZ. He is the
author of some of the world’s best-known creation
books. A former NZ chess champion, he works
for Creation Ministries International (in Australia
1996–2010, thereafter in Atlanta, USA). For more:
survival advantage, while the scallop
seems to have much more vision than it
needs. Like thousands of other features
in living things, the scallop eye testifies
to the engineering skill of its Creator.
References and notes
1. Palmer, B.A. and nine others, The image-forming mirror in the eye of the scallop,
Science 358(6367):1172–1175, 1 December
2017 | doi: 10.1126/science.aam9506.
2. Zimmer, C., The scallop sees with space-age eyes—hundreds of them, New York
Times, 30 November 2017; nytimes.com.
wide-field imaging devices
derived from this unusual form
of biological optics.”1
Animal eye expert Daniel Speiser, from
the University of South Carolina, is
amazed that such a simple shellfish
needs such advanced visual technology,
“It’s still a puzzle why they see so
well.” 2 Of course, the newspaper report
contains the required nod to evolution:
“His study shows that scallops
have evolved a mastery over
forming crystals, guiding them
into shapes that researchers
didn’t think possible.” 2
But how could ‘mastery’ have evolved
by slow and gradual changes generated by accidental changes to existing
genetic information (mutations), each
an advantage over the previous stage?
Natural selection selects only for
That is, guanine, one of the
DNA ‘letters’, is also the main
reflecting surface. But the scallop
manages to grow the crystals
in a square shape, although
guanine normally forms prisms.
This means that they are like
tiles fitting closely together, and
resemble “the segmented mirrors
of reflecting telescopes”.1
Also, guanine is mirror-like
only when it’s in thin multilayers,
otherwise it’s transparent. 2 The
scallop has 20–30 layers of the
tiled guanine alternating with
cytoplasm, the material inside
cells. The tiles are very thin, only
74 nanometres (nm) thick, and
separated by cytoplasm 86 nm
thick. This means that it is almost
perfectly efficient at reflecting
blue-green light with a wavelength
of 500 nm. This ‘happens’ to be
around the peak colour of the light
that penetrates the water to reach
the scallop, as well as the colour
that the eyes are most sensitive to.
Furthermore, the eye is not
symmetrical around the axis.
This is not a fault, but a designed
feature. It produces two separate
images focused onto two retinas.
Objects in the centre of view produce
images on the distal retina (further from
the body), while peripheral images
form on the proximal mirror (nearer to
the body). The distal retina is good at
detecting movement, so the scallop can
escape a predator. The proximal retina
is more sensitive, and provides information about the scallop’s surroundings.
The report concludes,
“The crystal morphology, multilayer structure, and 3D shape of
the scallop’s eye mirror are finely
tuned to produce functional
images on its two retinas.”1
It continues by explaining that this
“pave the way for the construc-
tion of novel bio-inspired
optical devices. In particular,
… the development of compact,
Fig. 1. The locations and anatomy of scallop eyes. (A) The scallop Pecten maximus with
numerous eyes lining the mantle (the white arrow points to an individual eye). (B) A
magnified image of five eyes. (C) Fluorescence microscopy image of an eye cross section,
showing the cell nuclei stained with DAPI ( 4′,6-diamidino-2-phenylindole). The (i) cornea,
(ii) lens, (iii) distal retina, (iv) proximal retina, and (v) concave mirror are indicated. (D)
Low-resolution cryo-SEM micrograph of an eye cross section after high-pressure freezing
and freeze-fracturing. The lens (blue), distal retina (yellow), proximal retina (orange),
and concave mirror (green) are shown in pseudo-colors. The cilia and microvilli of the
photoreceptors were used to identify the locations of the distal and proximal retinas.
Yellow arrows in (C) and (D), show the direction of on-axis incident light. From Ref. 1.