What do fiddler crabs see? by Shryl Francisco

Maria Nick Aedan

2024-09-27 02:43:17 UTC

Crabs cannot see the color of the plankton they eat at the bottom of the ocean floor; this is because no visible light can get to the ocean floor. Our first piece of evidence is evidence card A, this applies to most creatures with eyes, which is that you can see the color if the light reaches your eyes. The second piece of evidence for us is evidence card D, we found out that orange, yellow, and green light gets further to the ocean floor, however it does not get to the ocean floor itself, where the crab lives. This proves that no light can reflect off the plankton, meaning they cannot see. The third piece of evidence is evidence card E. It is another piece of proof that the deeper the fish are, the light cannot reflect off them anymore, meaning that the scientists cannot see them. Our last piece of evidence is from one of the articles, the medium (water) absorbs all the light before it transmits through the great distance all the way to the ocean floor, where it can’t be seen anymore. All these pieces of evidence support our claim that crabs cannot see the plankton they eat.

Yuhan, Mimi, Tony, Noel

2024-09-27 02:51:51 UTC

Yes, the crabs can see the plankton and the plankton appear green. According to evidence D, green and yellow are the only colors that can reach the seafloor, and since plankton can reflect all colors of visible light (evidence C) this would make all plankton at the seafloor appear green and yellow. However, according to evidence card F, algae absorbs all colors except green which is reflected. This suggests that green is the only color that will reach the seafloor and be reflected by Plankton, and therefor crabs (which see all colors of visible light according to evidence card A,) will see Plankton as green.

Although some may claim that visible light doesn't reach the ocean floor, the elevation of the ocean floor differs based on location, so in some places where crabs live the ocean floor may not be deep enough for green to not reach it.

“Light and Color in the Deep Sea - Deep Ocean Education Project.” Deep Ocean Education Project, 25 Apr. 2022, deepoceaneducation.org/resources/light-and-color-in-the-deep-sea.

“Ocean Floor Features.” National Oceanic and Atmospheric Administration, www.noaa.gov/education/resource-collections/ocean-coasts/ocean-floor-features.

Terry, Jacob, Elisa, and Eduardo CER

2024-09-27 02:55:32 UTC

Because no visible light is able to reach the ocean floor, where the plankton are, we can conclude that crabs cannot see the plankton they eat. Firstly, according to Evidence Cards G and B, algae reflects green light, causing it to bounce off in any direction. Also, there is a significant amount of algae on the ocean layer above where the crabs live. We know from Evidence Card F that algae absorbs every color from the visible light spectrum except green. This is significant as it proves that algae causes all colors of visible light to be reflected or blocked, meaning that there is no visible light on the ocean floor. Moreover, according to Evidence Card A, despite the fact that crabs can see all visible light, this can only happen if it reaches their eyes. Because we know that there is very little visible light on the ocean floor, we can conclude that crabs will not have any light reflected in their eyes. Lastly, according to the ScienceDaily scientific journal, "[crabs] have a sort of color vision combining sensitivity to blue and ultraviolet light." This demonstrates that crabs must have developed and utilize an alternative system of sensing their prey, which in this case is a heightened sensibility to UV light. Therefore, due to the evidence presented, we can determine that crabs cannot see plankton on the ocean floor given there being no visible light, and must resort to a heightened receptiveness of UV light.

Ellie Choi, Asa, Eddy, Stella

2024-09-27 02:55:32 UTC

Our claim is that crabs can not see the plankton underwater. Our first evidence is evidence card C. Evidence card C states that the plankton appears white under the water. This evidence supports our claim because White may be seen underwater but it's too dark for the light to reflect its color under water, so it's hard for the crabs to see the planktons. Another evidence is evidence card G. Evidence card G states that the light is reflected by Algae. This supports our claim because crabs cannot see the plankton underwater because algae reflects the light, which allows the light bounce off in any direction. Therefore, light might not be able to reach the ocean floor, which means there is not enough light being reflected for the crabs to see the plankton. Moreover, according to evidence card F, it mentions how Algae present in the water absorbs most colors of visible light, making it difficult for any light to reach the plankton and be reflected back in the crabs eyes. Additionally, unlike other aquatic animals, plankton do not have the ability to emit light on their own, making them invisible to crabs under these circumstances. The limited transmission of specific colors of visible light, such as orange, yellow, and green further contributes to the difficulty in visualizing plankton on the ocean floor or at deep depths.

Andrew, Rashulia, Ellie, JC

2024-09-27 03:05:26 UTC

Our claim is that crabs cannot see plankton. This is because visible light cannot reach the ocean floor. This is because of multiple things, such as the polarization of light when it hits water. When light is polarized through refraction, all the different wavelengths get dispersed in different directions, making it more susceptible to absorption by the water, or other things like algae. Another evidence is that even if the algae reflects the green lights, and green lights are available to reach the ocean floor, planktons can absorb all the colors including see, meaning that planktons are not visible to the crabs

Alto

16igarashia — 2024-09-27 03:12:14 UTC

Crabs cannot visually detect the plankton they eat on the ocean floor because there is not enough visible light at those depths for them to see color. Light must reach an animal's eyes for it to perceive color, but the ocean absorbs most visible light wavelengths, preventing them from reaching the deep areas where crabs live. Algae in the water absorb all colors except green, causing significant light reflection and scattering. While some orange, yellow, and green light can penetrate deeper, it does not reach the ocean floor. As you go deeper, light becomes unable to illuminate objects, making many organisms, including plankton, invisible to crabs. Plankton also do not produce their own light, further complicating visibility in the darkness. However, crabs have adapted by developing heightened sensitivity to blue and ultraviolet light instead of relying on visible light to find prey. In summary, the lack of visible light penetration, algae absorption, and plankton characteristics prevent crabs from seeing them at the ocean floor, leading crabs to use alternative sensory mechanisms to locate food sources.

(According to Evidence Card F, algae absorb nearly all colors of the visible light spectrum except for green, which leads to significant light reflection and scattering. This means that while some light may penetrate deeper layers, it is insufficient for visibility at the ocean floor.

Evidence Card D reveals that while certain wavelengths like orange, yellow, and green can travel deeper into the water column, they do not reach the ocean floor itself. Consequently, there is no reflected light available for crabs to perceive plankton.

Evidence Card E, as one descends deeper into the ocean, the ability of light to illuminate objects go away. This lack of illumination also goes to many organisms, including plankton, being invisible to crabs.

plankton typically do not emit light on their own. This characteristic further complicates visibility under low light conditions. Evidence Card C mentions that while plankton may appear white in water, the darkness at depth inhibits any reflection of color, making it difficult for crabs to identify them.)