The Visibility of Distant Objects

Duntley, Seibert Q.

doi:10.1364/josa.38.000237

Cited by 47 publications

(26 citation statements)

References 4 publications

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“…This simplification results in overestimating range. To predict the range at which an object becomes invisible, an observer's contrast threshold has to be accounted for (80). Contrast follows the same attenuation law as light [C R = C O e −σ(λ)r , where σ(λ) is the extinction coefficient, C R is the apparent observed contrast, and C O is the actual contrast of the object].…”

Section: Methodsmentioning

confidence: 99%

Massive increase in visual range preceded the origin of terrestrial vertebrates

MacIver

Schmitz

Mugan

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The evolution of terrestrial vertebrates, starting around 385 million years ago, is an iconic moment in evolution that brings to mind images of fish transforming into four-legged animals. Here, we show that this radical change in body shape was preceded by an equally dramatic change in sensory abilities akin to transitioning from seeing over short distances in a dense fog to seeing over long distances on a clear day. Measurements of eye sockets and simulations of their evolution show that eyes nearly tripled in size just before vertebrates began living on land. Computational simulations of these animal's visual ecology show that for viewing objects through water, the increase in eye size provided a negligible increase in performance. However, when viewing objects through air, the increase in eye size provided a large increase in performance. The jump in eye size was, therefore, unlikely to have arisen for seeing through water and instead points to an unexpected hybrid of seeing through air while still primarily inhabiting water. Our results and several anatomical innovations arising at the same time suggest lifestyle similarity to crocodiles. The consequent combination of the increase in eye size and vision through air would have conferred a 1 million-fold increase in the amount of space within which objects could be seen. The "buena vista" hypothesis that our data suggest is that seeing opportunities from afar played a role in the subsequent evolution of fully terrestrial limbs as well as the emergence of elaborated action sequences through planning circuits in the nervous system. fish-tetrapod transition | vision | visual ecology | terrestriality | prospective cognition B efore terrestrial vertebrates arose, their ancestors inhabited underwater environments, where vision is highly compromised compared with vision above water. The visual difference between life in water and life above it is comparable with driving fast on a foggy road, where our responses must be rapid and simple, vs. driving in clear daylight conditions, where deliberation over more complex choices is enabled by the vast increase in sensory range. Nonetheless, although an immense quantity of work has been done on the emergence of limbs during the evolution of land vertebrates, how visual capability changed during the transition from water to land has not been explored. In part, this lack of exploration is because computational visual ecology-necessary to interpret the fossil data-has not been combined with early tetrapod paleontology. Through combining these disciplines, here we probe the evolutionary history of the switch in our visual sensory ecology from water to air. Surprisingly, our results show that eyes tripled in size just before full-time life on land evolved. Convergent lines of evidence, including our own, strongly support the hypothesis that a crocodilian ecotype-using the greatly enhanced visual capabilities conferred by vision through air to prey on the bounty of unexploited invertebrates that long preceded the vertebrates onto ...

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Section: Methodsmentioning

confidence: 99%

Massive increase in visual range preceded the origin of terrestrial vertebrates

MacIver

Schmitz

Mugan

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…The reflectance was recorded between 300 and 700 nm (UV: 300-400 nm; visible spectrum: 400-700 nm) and measured relative to a WS-1 white standard. To mimic natural conditions, the light source was set at 45°to the meral spot surface and the collector was perpendicular [26,27]. Light source and collecting probes were 600 µm UV-VIS fibre-optic cables (Ocean Optics, Dunedin, USA) with collimating lenses attached to the end.…”

Section: Field Study: Variation In Meral Spot Reflectancementioning

confidence: 99%

“…Live stomatopods were immobilized by cooling them in a freezer (−13°C) for 30 min in 25 ml of water, and then pinning them out in a Petri dish with the meral spot facing up. The Petri dish was filled with just enough seawater to cover the meral spot [27]. All reflectance measurements were recorded in a dark box with only the light source illuminating the sample.…”

Section: Field Study: Variation In Meral Spot Reflectancementioning

confidence: 99%

A colorful world: Signaling in mantis shrimp

Franklin¹

2013

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Complex signals are commonly used during intraspecific contests over resources to assess an opponent's fighting ability and/or aggressive state. Stomatopod crustaceans may use complex signals when competing aggressively for refuges. Before physical attacks, stomatopods assess their opponents using chemical cues and perform threat displays showing a coloured patch, the meral spot. In some species, this spot reflects UV. However, despite their complex visual system with up to 20 photoreceptor classes, we do not know if stomatopods use chromatic or achromatic signals in contests. In a field study, we found that Neogonodactylus oerstedii meral spot luminance varies with sex, habitat and, more weakly, body length. Next, we conducted an experimental manipulation which demonstrated that both chemical cues and chromatic signals are used during contests. In the absence of chemical cues, stomatopods approached an occupied refuge more quickly and performed offensive behaviours at a lower rate. When UV reflectance was absent, stomatopods performed offensive behaviours more frequently and contest duration trended towards shorter fights. These results provide new evidence that UV reflectance and/or visible spectrum luminance is used to amplify threat displays. Our results are the first to demonstrate that chemical and chromatic cues comprise a multimodal signal in stomatopod contests.

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“…When the contrast of an object has been reduced to less than two percent, as a rough rule of thumb, it beccmes invisible. The loss of contrast can be calculated from the distance and particle-size, and visiblity ranges can be predicted, 1 In addition to this physical component of the whiteout phenomenon, there is also a physiological component. There are profound effects on the eye of this uniform visual stimulation throughout the visual field.…”

Section: Introductionmentioning

confidence: 99%

“…New techniques for measuring accommodation, however, have shewn that resting accommodation is not at infinity 1 and, moreover, the magnitude of myopia varies from one individual to another. 16 ' 1 ' Further, the various kinds of myopia -night myopia, instrument myopia, and empty-field myopia -are all about equal and can be predicted from the resting accommodation.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Visual Detection During 'Whiteout'

Luria¹

1982

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The Visibility of Distant Objects

Cited by 47 publications

References 4 publications

Massive increase in visual range preceded the origin of terrestrial vertebrates

Massive increase in visual range preceded the origin of terrestrial vertebrates

A colorful world: Signaling in mantis shrimp

Improvement of Visual Detection During 'Whiteout'

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