10
EVEN ACROSS OCEANS AND
millennia, nature finds a way to
arrive at the same solutions. Just
look at eyes: We share our lens-like
optics with distant species such
as octopuses, and our trichro-
matic spectrum of vision with
cer tain primates and marsupials
that evolved this third receptor
independently from us. These
traits all arose through classic
divergent evolution, in which
branches split off the tree of life as
animals fill ecological niches. Yet,
because some features address
common issues— the need to see
clearly, and in color— the adapta-
tions also represent an opposing
phenomenon called convergent
evolution. Here, we’ve illustrated
how both paths come together.
ABSTRACTED
BY SARA CHODOSH /
ILLUSTRATION BY JACQUI OAKLEY
origin of the
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LENS / Vertebrate eyes evolved
millions of years after we split from
cephalopods but share the same
basic design: Light enters a hole in
front and hits receptors in back.
TRICHROMACY / Our prede-
cessors copied and tweaked a
color-sensing cone, perhaps to spot
red fruit on leaves. A few other
mammals pulled the same move.
Sa
ur
op
si
da
MAMMALS
PLACENTALMAMMALS
PR
IMATES
DIRECTIONALPHOTORECEPTION
LOW-RESVISION
NOVISION
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SPRING 2020 / POPSCI.COM
HIGH-RESVISION
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