Those apart of the Mollusca phylum are known as mollusks. There are approximately 85,000 known species of these particular organisms, making mollusks the largest marine phylum there is. These organisms come in many different shapes, sizes, and colors and are bilaterally symmetrical. These organisms are ecologically beneficial because they do things such as provide food for other organisms in their ecosystem, recycle nutrients, plant and animal waste, and keep the water decontaminated and healthy. Mollusks live in many different habitats such as in oceans, rivers, rocky beaches, gardens and many more. Some mollusks have the ability to change color, while others can grow up to 16 meters long. This phylum is one of the most diverse out of all the phyla.
MOVEMENT: Some mollusks are mobile, while others are sessile. Terrestrial, mobile mollusks move at a slow and steady pace, using their “foot”, which is a flat sole on the bottom of their bodies. Aquatic, mobile mollusks move by jet propulsion. This occurs when the organism ejects water out of one of their body cavities, which then pushes them forward in the water. As for sessile mollusks, in most cases they attach themselves to objects such as rocks for their whole life, however if they need to move, it will be very minimal. The way that they slightly move is by flexing their foot, which will create tiny waves of motion, thus allowing the organism to move.
BODY COVERINGS: These organisms have more than two cell layers, and they have an organ-system grade of organization, meaning that groups of two or more tissue work together to make this organism function. Some mollusks such as such as snails and clams have an exoskeleton, which is an outer protective layer, protecting the soft parts of these organisms, while some have an hydroskeleton or flagella. Other organisms within this phylum protect themselves by camouflaging, releasing ink, having the ability to hide, and with the use of photophores.
SUPPORT: Mollusks are invertebrates. In order to maintain their body structures, some mollusks have an exoskeleton, hydrosekeleton, or a shell, while others rely on high internal body pressure.
NUTRITION: Some aquatic mollusks filter feed using their gills, while other mollusks use their harsh tongue, known as a radula. The radula is filled with multiple teeth made of chitin, that snatches the small plants and animals into their mouth, which then tears the food apart into chunks. Some organisms even have the ability to grab their prey with their tentacles, and disable it with its deadly saliva. Mollusks prey on several different organisms such as leaves, fruits, vegetables, rocks, plankton, tiny krill, small crustaceans and other animals such as fish.
RESPIRATION: Aquatic mollusks breathe with their gills, using tubes known as siphons, which bring in water as well as take it out of the organism’s body. Terrestrial mollusks lack gills, so instead they breathe with the help of their mantle cavity which has a large surface area that is lined with blood vessels.
CIRCULATORY: These organisms have a heart, blood, and blood vessels. In most cases, slow moving mollusks possess an open circulatory system, while faster moving mollusks have a closed circulatory system. In an open circulatory system, the mollusk’s gills will accumulate the blood, which is then pumped through the heart, and is then dispersed straight into spaces in the tissues. After this, the blood returns to the gills, and then to the heart, where the process is then repeated. A closed circulatory system functions with a hemocoel, which is a blood-filled space. This system transports the blood around the organism’s body much quicker than an open circulatory system does.
EXCRETION: Mollusks release their waste with the assistance of an opening that has flagella, cilia, and absorptive walls, known as the nephridia. These organisms have two kidneys, which accumulates liquid wastes from the coelom, which is dumped into the mantle cavity, and pumped out of the organism through their anus.
RESPONSE: Mollusks have a nervous system consisting of nerve ganglions, nerve cords, and sensory organs. These organisms have chemical and touch receptors, statocysts which keep mollusks balanced, as well as eyespots, and eyes. There organisms have a well-developed brain and can easily detect predators and prey.
REPRODUCTION: Some mollusks are hermaphroditic, while others are dioecious. Some reproduce sexually, while other mollusks reproduce asexually. To reproduce sexually, the organism must either self-fertilize their eggs, or two mollusks of the same species must mate, where the male fertilizes the female’s eggs. During the process of sexual reproduction, two gonads, which is a male’s sex organ, sit next to the coelom and shed sperm into it, where the nephridia releases the sperm into the mantle cavity. Sexual reproduction can also happen externally when a female releases her eggs into the water and the male fertilizes them after they are laid. Asexual reproduction can also take place through budding.
MOVEMENT: Some mollusks are mobile, while others are sessile. Terrestrial, mobile mollusks move at a slow and steady pace, using their “foot”, which is a flat sole on the bottom of their bodies. Aquatic, mobile mollusks move by jet propulsion. This occurs when the organism ejects water out of one of their body cavities, which then pushes them forward in the water. As for sessile mollusks, in most cases they attach themselves to objects such as rocks for their whole life, however if they need to move, it will be very minimal. The way that they slightly move is by flexing their foot, which will create tiny waves of motion, thus allowing the organism to move.
BODY COVERINGS: These organisms have more than two cell layers, and they have an organ-system grade of organization, meaning that groups of two or more tissue work together to make this organism function. Some mollusks such as such as snails and clams have an exoskeleton, which is an outer protective layer, protecting the soft parts of these organisms, while some have an hydroskeleton or flagella. Other organisms within this phylum protect themselves by camouflaging, releasing ink, having the ability to hide, and with the use of photophores.
SUPPORT: Mollusks are invertebrates. In order to maintain their body structures, some mollusks have an exoskeleton, hydrosekeleton, or a shell, while others rely on high internal body pressure.
NUTRITION: Some aquatic mollusks filter feed using their gills, while other mollusks use their harsh tongue, known as a radula. The radula is filled with multiple teeth made of chitin, that snatches the small plants and animals into their mouth, which then tears the food apart into chunks. Some organisms even have the ability to grab their prey with their tentacles, and disable it with its deadly saliva. Mollusks prey on several different organisms such as leaves, fruits, vegetables, rocks, plankton, tiny krill, small crustaceans and other animals such as fish.
RESPIRATION: Aquatic mollusks breathe with their gills, using tubes known as siphons, which bring in water as well as take it out of the organism’s body. Terrestrial mollusks lack gills, so instead they breathe with the help of their mantle cavity which has a large surface area that is lined with blood vessels.
CIRCULATORY: These organisms have a heart, blood, and blood vessels. In most cases, slow moving mollusks possess an open circulatory system, while faster moving mollusks have a closed circulatory system. In an open circulatory system, the mollusk’s gills will accumulate the blood, which is then pumped through the heart, and is then dispersed straight into spaces in the tissues. After this, the blood returns to the gills, and then to the heart, where the process is then repeated. A closed circulatory system functions with a hemocoel, which is a blood-filled space. This system transports the blood around the organism’s body much quicker than an open circulatory system does.
EXCRETION: Mollusks release their waste with the assistance of an opening that has flagella, cilia, and absorptive walls, known as the nephridia. These organisms have two kidneys, which accumulates liquid wastes from the coelom, which is dumped into the mantle cavity, and pumped out of the organism through their anus.
RESPONSE: Mollusks have a nervous system consisting of nerve ganglions, nerve cords, and sensory organs. These organisms have chemical and touch receptors, statocysts which keep mollusks balanced, as well as eyespots, and eyes. There organisms have a well-developed brain and can easily detect predators and prey.
REPRODUCTION: Some mollusks are hermaphroditic, while others are dioecious. Some reproduce sexually, while other mollusks reproduce asexually. To reproduce sexually, the organism must either self-fertilize their eggs, or two mollusks of the same species must mate, where the male fertilizes the female’s eggs. During the process of sexual reproduction, two gonads, which is a male’s sex organ, sit next to the coelom and shed sperm into it, where the nephridia releases the sperm into the mantle cavity. Sexual reproduction can also happen externally when a female releases her eggs into the water and the male fertilizes them after they are laid. Asexual reproduction can also take place through budding.