Octopuses, squid, cuttlefish, and nautiluses are all of the mollusk class, Cephalopoda, translated to “head foot.” Ancient Cephalopods have been dated back to the late Cambrian period. Unlike other mollusks, cephalopods internalize and reduce their shells to cuttlebone in cuttlefish, pen in squid, and absent altogether in octopi. Cephalopods are found all around the world and inhabit marine waters from tropical to near freezing and from shallow to the deep abyss. Today, there are about 800 species of cephalopods. Cephalopoda has an intelligence unlike any other invertebrate. The mollusk class has been deemed the smartest of all invertebrates. In particular, octopuses have a brain-to-body mass ratio that is higher than vertebrates such as fish …show more content…
and reptiles (Dale, 2007). Cephalopods live a complex enough lifestyle that requires an elaborate and sophisticated sensory and nervous system. Out of all the invertebrates, cephalapoda has evolved the most efficient sense organs and impressive nervous system. These thought to be simple invertebrate systems even rival the vertebrate equivalents in sophistication. (Budelmann, 1994). Cephalopods have a highly developed nervous system which is well known to neurophysiologists especially the giant axon of some squids and cuttlefish. A cephalopods sense organs are also sophisticated with lensed eyes that have high acuity. All of these aspects pertaining to Cephalopoda are the foundation to their sophisticated visual and tactile learning and memory including associative learning, spatial learning, and observational learning (Ikeda, 2009). Learning can be social, environment-dependent or self-taught. Cuttlefish are social compared to isolated octopuses. An octopus’s ability to learn can be traced back to environment-dependent factors. Their learning capability can also be linked to physical aspects such as their set of eight arms with suction cups. This physical feature presents an excellent piece of equipment for exploration and tool use (Mather, 2006). A type of learning termed conditional discrimination associated primarily with vertebrates has also been tied to cuttlefish and octopuses. This such learning can include recognition of landmarks, use of directional information provided by cues, and mechanisms that record internal information (Hvorecny, 2007). Before recent studies on cephalopods, invertebrates have been regarded as inferior when it comes to linking cognitive abilities and the engagement of sophisticated behaviors together.
These particular invertebrates have been found to physically manipulate their environment by prey manipulation, burying and den excavation, arm dexterity, den barricading with rocks/coral. The observations of such behaviors have led scientist to believe cephalopods have the capacity to employ tools (Finn, 2009). Cephalopoda is also known for their body-patterning abilities for interspecific and intraspecific communication. The cephalopod skin has been deemed a very complex and sophisticated organ in itself. Cephalopoda skin colors and textures are regulated by intricate neuromuscular mechanisms. Chromatophores are the reason behind their skin appearance. Chromatophores are large pigment-containing cells distributed in the superficial layers of the skin over the whole surface of the body. By equal and unequal dilation of chromatophores, a variety of patterns and colors are produced causing the animal to become darker, lighter (Barbato, 2007). The Cephalopoda’s sophisticated development, their ability to learn, and the how they can physically manipulate their environment pronounces them the most intelligent …show more content…
invertebrate. SOPHISTICATED SENSE ORGANS It is no surprise how sophisticated cephalopods eyes and vision are. Cephalopods have well developed eyes and complex vision behavior. These characteristics can be described in detail from data that dates from 1835 to recent. In early cephalopods, Nautilus, eyes were simple but in more recent species, the eyes can be compared to the vertebrate eye. A cephalopod eye is comparable to the camera eyes of vertebrates particularly fish with respect to speed, resolution and sensitivity. They have also been compared to other animals such as birds that have good vision especially when detecting polarized light where they have the ability to build receptor systems capable of analyzing polarization of incoming light. One species in particular, the deep-sea vampire squid, eyesight has even been compared to humans. When in murky water, deep-sea, or at night, cephalopods then rely on their lateral line system along with rows of sensitive epidermal hair cells. This attributes allow species to detect a moving fish of 1 meter in body length from a distance of about 30 m (Budelmann, 1994). The giant axon in the cephalopod nervous structure is the most sought out. It has become extremely valuable in nerve impulse conduction and transmission studies and research. Large fibre systems are necessary for fast escape reactions especially in escape-jetting cephalopods. The giant axon serves to increase the degree of muscle response. Cephalopoda has by far the most complex brain of all invertebrates. Their brains contain between 100-200 million nerve cells and their peripheral nervous system has over 350 million cells. The millions of cells in each system have been connected to the complexity of the coordinated movements and reflexes done by their multiple arms and suckers. Countless of past studies and on going research has determined Cephalopoda being the most vertebrate-like of all invertebrates. COMMUNICATION The cephalopod skin is one of its most complex and sophisticated organs. Chromatophores are large pigment containing cells distributed in the superficial layers of the skin distributed all over the body’s surface. The movements of these chromatophores are the cause for the changes in the appearance of a cephalopods skin. These elaborate neuromuscular mechanisms regulate the skins colors and textures (Barbato, 2007). The skin can change rapidly and immediately due to a response such as a prey attack or recognizing a prey. One such species, can change color and texture in order to match background and disorient the prey during an attack on a prey. These chromatophores have been found to be used in communicative systems by transferring information to both potential predators and conspecifics, or relatives of the same species. These are especially noticeable during courtship rituals and cautious situations. Some species have been recognized to interact with a pattern-based language. There are several advantages from this kind of communication amongst Cephalopoda such as the rapidity of signaling and change of signals, the ability to rank the intensity of signals, the possibility for bilateral signaling as well as limited interference between the multiple signals and other ongoing motor acts (Barbato, 2007). LEARNING Numerous of research has concluded how dependent cephalopods are on learning. Behaviors are determined by exploration, learning, forgetting and re-learning. Unlike cuttlefish and squid, octopuses are anti-social and thus depend on their environment. In particular, octopuses use trial and error learning. Octopuses have also been determined to support spatial orientation by learning and has even been confirmed by maze experiments. Studies on cuttlefish and octopuses have shown their ability to discriminate. In order to discriminate, these organism have the ability to selectively respond to one out of multiple stimuli that are either presented simultaneously or in sequences (Hvorecny, 2007). TOOL USE Documented tool use amongst animals has been seen in primates, mammals, and birds, a defining feature of humans.
This has yet to be seen in invertebrates until Cephalopoda. Octopuses have been observed carrying around potential tools and assembling them when needed. Until these observations, invertebrates have not been known to have such cognitive abilities that are needed to engage in sophisticated behaviors such as tool use. One particular octopus species, the veined octopus, has been known to use a specific tactic called stilt walking that allows them to carry coconut shell halves and use them to build shelter against predators. Complex cognitive processes such as planning, problem-solving, and environment manipulation are indicators of rational thought as well as tool use. This further enhances the Cephalopoda
intelligence.
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
Ceratopsians and Pachycephalosaurs Around 144 million years ago, began the emergence of the Ornithischian dinosaurs during the Cretaceous period and diversified into North America and Asia. Ornithischians were classified as having a hip structure similar to that of birds, although they are not the descendants of birds. Marginocephalians, meaning "fringed heads" are a group of Ornithischians that have a distinctive skull structure, consisting of a slight shelf or bony frill on the back of the skull, a unique palate, and a short hip structure. These herbivores include two major groups: the Ceratopsians and the Pachcephalosaurians. These plant-eaters include the Ceratopsians, horned dinosaurs such as the Triceratops, Styrachosaurus, Pentaceratops, and the Protoceratops.
One hundred and fifty million years ago, large aquatic species of reptile such as the Plesiosaur dominated the ocean, and were pre-eminent predators of the sea. The branch of now extinct Plesiosaurs, or ‘near lizards’, evolved into variant closely related species specialised to take different niches in the food chain. Such species of Plesiosaur include the phenotypically similar Plesiosauroid and Pliosauroid. The physiological adaptations of the long necked variant, the Plesiosauroid, as it relates to deep sea diving, will be addressed in depth.
Cephalopods are known to be exceptionally intelligent by invertebrate standards and in some respects even rival “higher” vertebrates. These animals have many highly evolved sensory and processing organs that allow them to gain a greater understanding of their environment and their place within it. Due to their advanced structures, many of which are analogous to vertebrate structures, and abilities they have been widely studied. Their methods of learning have been of prime interest and many experiments have been conducted to determine the different ways in which octopuses can learn. From these experiments four main kinds of learning have been identified in octopuses: associative learning, special learning,
The crustacean moult cycle is initiated when the Y-organ in the head secretes the hormone Ecdysone (E) into the circulatory system[3,4,5]; the Y-organ is the primary source of E[5]. Upon contact with the haemolymph (a combination of blood and tissue fluid) within the circulatory system E is converted to its active form, 20-hydroxyecdysone (20E), by a P450 enzyme[4]. This causes the epidermal cells to secrete moulting fluid, which contains a mixture of enzymes such as proteases and chitinases. The moulting fluid degrades the exo- and endocuticle, and the digested cuticle is reabsorbed to create new cuticle; moult fluid also has a role in initiating the moult. The degraded cuticle is replaced by water or air so that the animal can swell in order to lose the shell. During the passive phase of the moult cycle, the shell splits along the break point caused by the decalcification of the shell, in the crab this is along the epimeral lines. Once the shell has split, the animal wiggles side-to-side to free itself from i...
In the phylum Mollusca, there are many organisms that have body parts that change as the environment around them change; such as the octopus. An octopus can camouflage to variety of objects in its environment. Each organism in the Mollusca phylum has a type of foot that stows mobility and they eat by a radula. The radula is strap like tongue that has very sharp teeth and they can change to be different shapes or sizes based on their prey. They have a pseudo coelomate body plan, meaning that they have a coelom that exists, but it is lined by mesoderm only on the body wall, not around the gut. This video enhanced my understanding standing of the phylum Mollu...
The Pacific Northwest tree octopus is close to extinction! It needs our help, so please try to help it by reducing the amount of pollution you put into the air. It lives on the west coast of the Olympic Peninsula in North America. Their habitat is on the eastern side of the Olympic mountain range, close to the Hood Canal. (Lyle Zapato)
In the early 1800’s, a new discovery that left paleontologists in awe was the fossil finding of the immeasurable amount of species of reptiles, Ichthyosaurs. Greek for “fish lizards”, these fossils were found all over the world. Because these large aquatic reptiles migrated just as whales do today, paleontologists have had the amazing advantage of collecting fascinating bone fragments throughout the past 177 years. Ichthyosaurs swam the ocean life from about 245 million until about 90 million years ago- approximately the same time dinosaurs ruled the land. The earliest Ichthyosaur fossil findings were in parts of Canada, China, Japan, and possibly Thailand. Countless fossils came from coatings of limestone produced out of the ocean-floor ooze that was predominantly superior at preserving very well facts of the creatures it digested (Perkins 2).
“The skin of amphibians is water permeable, well supplied with glands, and often colorful, with the colors and patterns of many salamanders and anurans rivaling those of brightly colored birds. It performs many functions. It protects against abrasion and pathogens, serves as a respiratory membrane, perhaps marginally so in caecilians, absorbs and releases water, provides some dry-land species during droughts with a water-loss-resistant cocoon, and through color change (in some species) a...
Humans have only discovered less than five percent of the ocean, while the ocean makes up seventy percent of our world. Even though we have explored so little of it, we have found very interesting creatures such as giant squids, yeti crabs, and zombie worms. None of these animals are similar in any way, not even their habitats, appearances, or diets. However they use these factors to be able to survive in sometimes extreme conditions.
The early tetrapods were the first vertebrates to actually walk the solid earth. They began their conquest of land in the Paleozoic era around 360 million years ago. The question many paleontologists have been asking for a long period of time is whether the anatomy for locomotion on land was developed in water for swimming purposes, or if it was adapted after the creatures became terrestrial. Recent findings of fossils indicate that the transformations of the aquatic creatures happened underwater in order to help them survive in the changing world. When looking for answers, they had to examine forearm, hip, wrist, finger, and other bones, as well as the lungs or gills of the early tetrapod fossils. This information is critical in understanding the history and the process of growth and change. It aids in learning about human evolution.
Liubicich, D.M., et al. 2009. Knockdown of Parhyale Ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology. PNAS 106 (33): 13892-13896
While most species of octopus live in shallow water there are some octopuses that are able to make a home in much deeper and cooler waters. The Dumbo Octopus, obviously getting its name from the famous Walt Disney elephant, is one of these creatures. Octopi are isosmotic, which means to have the same isosmotic pressure. This allows octopi to live in deeper waters without freezing to death. The Dumbo Octopus usually lives at a sea depth ranging from 1,300 to 23,000 feet.
Chameleons have special cells that allows it to change colors. These special cells are called chromatophores (Raxworthy, 2004). They contain layers of pigments that lie below their outer skin. Dispersion of the pigment granules in the chromatophores determines how deep the color is. When the pigment is equally distributed in a chromatophore, the whole cell is deeply colored. When the pigment is located only in...
First of all, an octopus is a cellapod. Which means it has a soft body, and no bones. An octopus also has eight arms, large useful eyes, and suction cups. ( Octopuses and Squid, page 6 by: Tori Miller.) All of these traits are mostly used for hunting. Eight arms come in handy when your prey is fast and can get away easily, large eyes are useful when you need to see in the dark or the depths of the ocean, and suction cups are used when they need to grab hold of something.( Octopuses Squid, page 14.) ( National Geographic, Octopus Facts.) Octopuses have blue blood caused by copper and bag like bodies. When born they're 1/4 of an inch and don't rely on...