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Suggestions and Addition

Suggestions

https://en.wikipedia.org/wiki/Octopus 1)Fourth Defense In the section talking about an octopuses fourth defense, more can be said about the different situations in which they employ this. The octopus will mimic different animals in different situations. An example would be when attacked by a damselfish, the octopus will mimic a sea-snake. Most likely scaring the damselfish away because the sea-snake is a predator of the damselfish. [1] Ignasiak.6 (talk) 00:32, 1 October 2014 (UTC)

Norman, M.D., J. Finn, and T. Tregenza. 2001. Dynamic Mimicry in an Indo-Malayan Octopus. Proceedings: Biological Science 268:1755-1758.

https://en.wikipedia.org/wiki/Anti-predator_adaptation Crypsis and Mimicry 2)For the crypsis section, more can be added on the different types of crypsis and mimicry and their relations to one anther. This will help people better understand the differences between them. In an article by John Endler, he has a table showing these relations and definitions.[1]This will help to better distinguish between these terms. 3)Another suggestion for mimicry would be to talk about behavioral mimicry, when an animal mimics the movement of a model animal. The animal avoids detection by mimicking movements of a less preyed upon species. This has been documented in octopus species. Ignasiak.6 (talk) 00:45, 1 October 2014 (UTC) Endler J.A.. 1981. An overview of the relationships between mimicry and crypsis. Biological Journal of the Linnean Society 16:25-31.

Addition

https://en.wikipedia.org/wiki/Anti-predator_adaptation

A third morphological defense mechanism is the ability of some octopuses to mimic different animals. The octopus mimics the model by changing their skin color and pattern to match the model and moving in a motion similar to the model. An octopus can mimic several models, and it makes a decision by determining the best form to deter the predator. An example being when damselfish attack an octopus, the octopus will mimic a banded sea-snake by threading six arms down a whole and raising the other two in opposite directions. The two raised arms are banded, mimicking the pattern of the sea-snake. The sea-snake is a predator of the damselfish, therefor by mimicking the sea-snake the octopus deters the damselfish.

Topic: How has camouflage and mimicry increased the fitness of octopuses by being an anti-predation defense.

Annotated Bibliography

Hanlon, R.T., L. Conroy, and J.W. Forsythe. 2008. Mimicry and foraging behaviour of two tropical sand-flat octopus species off North Sulawesi, Indonesia. Biological Journal of the Linnean Society 93:23-38.

This paper by Hanlon, Conroy and Forsythe questions if octopi can adapt their body pattern and behavior to mimic multiple species of marine life. Three species of octopus were followed throughout the day and videotaped by divers. The octopi were first habituated to the divers so they acted naturally. The researchers found that the octopi spent a majority of their time in their den, usually mimicking sessile invertebrates. When the octopi were moving over large areas they mimicked a flounder. The mimic varied based on habitat. They concluded that the octopi had a good mimic of a flounder but were never seen mimicking other moving animals. The study did not observe the flounder after which the octopi were mimicking, limiting their knowledge of how accurate the mimic was. This paper demonstrates how the octopi’s primary defense relates to the environment the octopus lives in. The researchers talked about similar papers to prove this point.

Hanlon, R.T., J.W. Forsythe, and D.E. Joneschild. 1999. Crypsis, conspicuousness, mimicry and polyphenism as antipredator defences of foraging octopuses on Indo-Pacific coral reefs, with a method of quantifying crypsis form video tapes. Biological Journal of the Linnean Society 66:1-22.

The researchers hypothesized that octopi remain highly camouflaged as their primary defense against predators. Snorkelers videotaped several octopi from dawn till dusk. The video was then watched and the level of crypsis graded on a five level rank from conspicuous to highly cryptic. They found that octopi in different habitats had different amounts of time in the different ranks of crypsis. But overall, they were often conspicuous. The researchers concluded that they lower their cryptic level if no predators are around. And they rapidly change their level of crypsis to disallow predators to form a search image. This study is important because it shows the different levels of crypsis octopus use as an anti-predator defense.

Norman, M.D., J. Finn, and T. Tregenza. 2001. Dynamic Mimicry in an Indo-Malayan Octopus. Proceedings: Biological Science 268:1755-1758.

The authors of this paper looked at the mimicry that is employed by the mimic octopus. They video recorded nine adult mimic octopuses over sixteen days to record behaviors and mimics. They found that the mimic octopus mimics three toxic animals: the flatfish, lionfish, and banded sea snake. Moreover, the octopus used these mimics in different situations. They concluded that complex mimics might have been naturally selected. The study is also important because it talks about the genetics behind mimicry.

Endler J.A.. 1981. An overview of the relationships between mimicry and crypsis. Biological Journal of the Linnean Society 16:25-31.

The author went through the definitions and relationships of mimicry and crypsis to help readers better understand the difference. He went through several definitions of each word and made a table of the new classes. He came up with six major classes compared to the two previous ones. John, the author, came up with these classes by looking at the interaction of the model, the mimic, and the operator. This article helps readers understand the differences between mimicry and crypsis.

Hanlon, R.T., A.C. Watson, and A. Barbosa.2010.A “Mimic Octopus” in the Atlantic: Flatfish Mimicry and Camouflage by Macrotritopus defilippi.Biological Bulletin 218:15-24.

The researchers stated that octopi use camouflage and mimicry to avoid predators. Divers observed and videotaped octopi that they came across off the coast of Saba. They found that the octopi swam like flounders, with a similar motion and speed. While swimming like a flounder, the octopi remained camouflaged. They concluded that mimicking another animal while moving is a primary defense used by octopi. This study is important because the octopi were found in the Atlantic Ocean. An area far away from where the mimic octopus is found, meaning more then one species of octopi utilize mimicry.

FINAL DRAFT STARTS HERE

Octopuses use mimicry and camouflage as anti-predator defenses Evolutionary arm races have long shaped organisms throughout evolutionary time. The relationship focused on in this paper is prey-predator. The pressures placed on the organisms by each other are important in the evolutionary fate of each organism. Prey are always trying to develop adaptations that will allow them to avoid predation. All the while predators are trying to develop adaptations to find prey. Since these adaptations are happening simultaneously it means that the prey and predator are co-evolving. In this evolutionary arms race there is no clear winner, as both are always evolving. One example of this arms race is octopuses and their predators. Octopuses employ both mimicry and camouflage as anti-predator defenses. They have long been in an evolutionary arms race with their predators and these defenses are ways by which they have adapted to their environment to evade predation. If an octopus lives to be reproductively successful its genes will be passed on to the next generation meaning that the octopuses that can survive to reproduce are selected for. It is from this selective pressure that octopuses have evolved the complex mechanisms of their impressive mimicry and sophisticated camouflage. Mimicry is when an octopus resembles a model to avoid detection. It can achieve resemblance by displaying a similar pattern to the model or by mimicking a models shape and movement to avoid detection, a technique termed locomotor mimicry (Hanlon et al. 2010). Camouflage occurs when an octopus changes the coloration of its skin. It can either match its body to the background, termed crypsis, or use bold contrasting colors along the edge of its body to break up its outline (Endler 1981). This is considered disruptive coloration because it disrupts the octopus’s body outline. Select species of octopuses can mimic many different types of models. Scientists believe that most of these octopuses use Batesian mimicry; the octopus models itself after an organism repulsive to predators. Therefore making the octopus appear less palpable. There is a strong benefit to the octopus for using Batesian mimicry, because octopuses are easily eaten due to their soft bodies, mimicking a repulsive organism gives them a fitness advantage (Holen and Johnstone 2010). An octopus that can mimic different models is selected for. Selection would be expected to favor the evolution of mimicry of many different models due to the fact that predators form search images; a search image is when a predator has an increased accuracy of discrimination for specific prey in its environment. It is a trait that predators possess to make finding prey easier and is a product of the evolutionary arms race. The octopus that employs a unique form of mimicry would be less likely to be eaten because the predator likely does not have a search image for that form (Norman et al. 2001). As noted earlier, octopuses can mimic a wide range of models. The different models it mimics depend upon its environment. Each environment has different selection pressures that lead to the evolution of different mimic forms in octopuses. Octopuses found in a rich habitat will go between camouflaging with the background and conspicuously mimicking different models because predators have many places where they can hide (Hanlon et al. 1999). While octopuses found in open areas such as sand plains, move across the area by mimicking inedible and sometimes inanimate objects such as rocks, corals, and clumps of algae (Hanlon et al. 2010). This is an example of deceptive resemblance, where the octopus resembles an inanimate object in its environment (Messenger 2001). This shows how environment impacts the evolution of an organism. Each environment has different selection pressures, the strongest of which is predators. The different models the octopus can mimic will provide different benefits. It is optimal for the octopus to mimic inanimate objects in open areas because there are many inanimate objects around the octopus, making it easy for the octopus to be inconspicuous in its environment. Within each environment an octopus will have to deal with a number of different situations and each octopus can deal with these situations in a number of different ways. If an octopus mimics a model a predator finds palpable, the octopus is likely to be eaten. This is why octopuses use decision-making skills (Hanlon et al. 1999). The octopus will look at context clues, such as the predator and habitat, to determine the model that will provide the most benefits. For example if an octopus is attacked by a damselfish it will mimic a banded sea snake, a predator of the damselfish, making the damselfish leave the octopus alone (Norman et al. 2001). If the octopus had mimicked another model, it may not have been as effective and may have led to injury or death, likely eliminating that individual’s genes from the gene pool. Another aspect of an octopus’s primary mimic defense is when an octopus remains conspicuous while foraging. A predator will be drawn to the movement associated with foraging, so camouflage is not as beneficial as mimicry. Octopuses will mimic a model, such as a flatfish, while moving across the environment. By mimicking a flatfish, the octopus interferes with a predator being able to associate a search image with its normal outline. The predator associates the swimming octopus with a flatfish, an un-palpable fish, rather than an octopus, a palpable one. The octopus mimics the flatfish by swimming forward with its arms trailing behind it and undulating. Flatfish are more rigid than octopuses and may be toxic, making them un-palpable to predators (Hanlon et al. 2010). Flatfish may also be too large for the predator to eat, so it leaves the octopus alone (Huffard et al. 2010). Mimicking flatfish also provides the octopus with other benefits. When an octopus is mimicking a flatfish, it swims close to the substrate; by doing this it moves faster due to lift. Since it is close to the substrate it can quickly camouflage if a threat is perceived. In this mimic form, the octopus’s eyes are directed forward to help with foraging. Another aspect of this mimic form is that the arms are more exposed, therefore protecting its body if it is attacked (Hanlon et al. 2010). Octopuses can regenerate arms but they cannot regenerate bodies. An octopus is also well adapted to camouflage. The octopus’s ability to camouflage among a range of models is due to neural polymorphism. Polymorphism is when an organism can be found in a variety of forms and colors, usually due to genetics. Though each octopus does carry different genes, each octopus itself is polymorphic because their appearance is not fixed; it is an ever-changing thing. An octopus can rapidly change its appearance due to the chromatophore organs it possesses (Messenger 2001). These are sacs in the outer layer of skin in the octopus, containing yellow, red or brown pigment. When muscles pull the sac out, the color shows. The opposite is true for when the muscles are relaxed. The muscles around the chromatophores are each connected to nerves, allowing for the rapid change in appearance. Underneath the chromatophores are a layer of reflecting cells that reflect some of the colors in the environment when the muscle are contracted. Octopuses can also use muscles in their skin to change their skin texture by pulling the muscles into peaks, making the skin smooth or rough (Mather et al. 2010). Octopuses are most often camouflaged while stationary (Hanlon et al. 2008). By blending in with the background, they are less likely to be spotted by a predator and eaten. Octopuses commonly sample a part of the background to use as their coloration, a type of camouflage termed crypsis (Endler 1981). This is why octopuses can regulate their camouflage for each microhabitat they interact with (Hanlon et al. 2010). Octopuses may also employ disruptive patterning, another type of camouflage. Disruptive patterning is when an animal breaks up its outline, interfering with the predators search image (Huffard et al. 2010). The octopus achieves this by contorting, flattening, or partially burying its malleable body (Hanlon et al. 1999). The octopus can also achieve disruptive patterning by changing its coloration. It does this by having bold contrasting colors along the edge of its body to break up the octopuses outline. This type of camouflage has been found to be very effective (Cuthill et al. 2005). This is another example of how octopuses have evolved anti-predator defenses. They moved forward in the arms race by evading deception by interfering with predator’s ability to form and use search-images, a mechanism evolved by predators to easily find prey. Both mimicry and camouflage have advantages that may lead to a higher fitness. This is key in the evolution of anti-predator defenses. The traits with the highest fitness survive and are passed onto future generations, shaping octopuses throughout evolutionary time. Since mimicry and camouflage proved to be successful, octopuses still possess these traits. In the future, researchers should observe different octopus species in different environments. By doing this they could see the different types of models the octopuses mimic and how they mimic them. They can also see the situations in which octopuses use camouflage compared to mimicry. The researchers should also observe interactions between the model and predator to see if the octopuses have chosen effective models. If the predator leaves the model alone, the octopus chose an effective model. If the predator attacked or killed the model, then the model is not effective. In addition to the observations, the researchers should test the models, if they are living creatures, to see if they are toxic. If the model is toxic, the octopus could be employing Batesian mimicry. All of this information would help scientists to learn more about the effect of the environment in the evolution of octopuses and the decision making that octopuses employ when dealing with different situations.

References

Cuthill, I.C., M. Stevens, J. Sheppard, T. Maddocks, C.A. Párraga, and T.S. Troscianko. 2005. Disruptive coloration and background pattern matching. Nature 434: 72-74.

Endler J.A.. 1981. An overview of the relationships between mimicry and crypsis. Biological Journal of the Linnean Society 16:25-31.

Hanlon, R.T., L. Conroy, and J.W. Forsythe. 2008. Mimicry and foraging behaviour of two tropical sand-flat octopus species off North Sulawesi, Indonesia. Biological Journal of the Linnean Society 93:23-38.

Hanlon, R.T., J.W. Forsythe, and D.E. Joneschild. 1999. Crypsis, conspicuousness, mimicry and polyphenism as antipredator defences of foraging octopuses on Indo-Pacific coral reefs, with a method of quantifying crypsis form video tapes. Biological Journal of the Linnean Society 66:1-22.

Hanlon, R.T., A.C. Watson, and A. Barbosa.2010.A “Mimic Octopus” in the Atlantic: Flatfish Mimicry and Camouflage by Macrotritopus defilippi.Biological Bulletin 218:15-24.

Holen, O.H., and R. A. Johnstone. 2004. The Evolution of Mimicry under Constraints. The American Naturalist 164: 598-613.

Huffard, C.L., N. Saarman, H. Hamilton, and W.B. Simison. 2010. The evolution of conspicuous facultative mimicry in octopuses: an example of secondary adaptation?. Biological Journal of the Linnean Society 101: 68-77.

Mather, Jennifer A., R. C. Anderson., and J.B. Wood. Octopus: The Ocean's Intelligent Invertebrate. Portland, Or.: Timber, 2010. Print.

Messenger,J.B.. 2001. Cephalopod chromatophores: neurobiology and natural history. Biological Reviews of the Cambridge Philosophical Society.76: 473-528

Norman, M.D., J. Finn, and T. Tregenza. 2001. Dynamic Mimicry in an Indo-Malayan Octopus. Proceedings: Biological Science 268:1755-1758.

SECOND ADDITION
https://en.wikipedia.org/wiki/Anti-predator_adaptation

The different models it mimics depend upon its environment. Each environment has different selection pressures that lead to the evolution of different mimic forms in octopuses. Each environment has different selection pressures, the strongest of which is predators. The different models the octopus can mimic will provide different benefits depending on the situation the octopus is in and each octopus can deal with these situations in a number of different ways. If an octopus mimics a model a predator finds palpable, the octopus is likely to be eaten. This is why octopuses use decision-making skills. The octopus will look at context clues, such as the predator and habitat, to determine the model that will provide the most benefits. If the octopus mimics a model that is not effective it may be injured or eaten and likely have its genes eliminated from the gene pool. Scientists believe that most of these octopuses use Batesian mimicry; the octopus models itself after an organism repulsive to predators. Therefore making the octopus appear less palpable. There is a strong benefit to the octopus for using Batesian mimicry because octopuses are easily eaten due to their soft bodies, mimicking a repulsive organism gives them a fitness advantage. An octopus that can mimic different models is selected for. Selection would be expected to favor the evolution of mimicry of many different models due to the fact that predators form search images; a search image is when a predator has an increased accuracy of discrimination for specific prey in its environment. It is a trait that predators possess to make finding prey easier and is a product of the evolutionary arms race. The octopus that employs a unique form of mimicry would be less likely to be eaten because the predator likely does not have a search image for that form.