We’ve all what animals see. Do they see the same way humans do in terms of colors, or is the vision of each animal based on their environment? Now, scientists might finally have the answer.
In a recent study published in Proceedings of the Royal Society B: Biological Sciences, biologists successfully gathered vision data for hundreds of vertebrates and invertebrates, strengthening scientists' understanding of animal vision, including what colors they see. The researchers determined that land-adapted animals are able to see more colors than water-adapted ones. It was also determined that terrestrial-adapted animals see a wider range of colors than forest-adapted animals.
However, evolutionary history -- also known as the difference between vertebrates and invertebrates -- significantly influences which colors a species sees. As it turns out, invertebrates see more short wavelengths of light compared to vertebrates.
"Scientists have long hypothesized that animal vision has evolved to match the colors of light present in their environments," says Erica Westerman, a biological sciences assistant professor at the University of Arkansas and co-author on the study. "But this hypothesis is difficult to prove, and there is still so much we don't know about animal vision. Gathering data for hundreds of species of animals living in a wide range of habitats is a monumental task, especially when considering that invertebrates and vertebrates use different kinds of cells in their eyes to turn light energy into neuronal responses."
The study demonstrated that animals' ability to adapt can be physiologically constrained, despite them being able to adapt to their surroundings environments. Vertebrates and invertebrates broadly use the same cell type, opsins, to see, but they build these cells differently. This physiological difference -- ciliary opsins in vertebrates and rhabdomeric opsins in invertebrates -- could explain why invertebrates are better at seeing short wavelength light, even when habitat should select for vertebrates to also see short wavelengths of light.
However, the difference could be due to stochastic genetic mutations occurring in vertebrates but not invertebrates, Westerman said. These mutations could also limit the range of light in vertebrates' vision.
"Our study answers some important questions," says biological sciences doctoral student and lead author Matt Murphy, "but it also generates more questions that could help us understand animal vision even better. We can do more to assess differences in the structure of the vertebrate and invertebrate retinae, or how their brains handle visual information differently. These are exciting questions."
As always, keep doing science & keep looking up!