User:M4TT262/sandbox

Characteristics:

Bony fish do not produce placoid scales, instead they consist of three types of scales that do not penetrate the epidermis. The three categories of scales for osteichthyes are cosmoid scales, ganoid scales, teleost scales. The teleost scales subdivided by cycloid scales and ctenoid scales. All of these scales have a base of bone that they originate from. The only difference is that the teleost scales only have one layer of bone. Ganoid scales have lamellar bone and vascular bone that lays on top of the lamellar bone, then enamel on top of the vascular bone. Cosmoid scales have the same two layers of bone that ganoid scales have, with the addition of dentin between the enamel and vascular bones and between vascular and lamellar bones, as well. These scales are found underneath the epidermis and do not break the epidermis of the fish, unlike placoid scales which poke through the epidermal layer.

           Mucus is also secreted onto the Osteichthyes epidermis layer. This mucosal layer has antibacterial properties. Allows for the fish to be streamlined in water allowing for greater speeds to be achieved. Thus, allowing for the fish to cut through the water with ease[TM1]. Since there is less opposing force acting on the fish. Mucus is secreted from a unicellular gland that is found in the epidermis layer of the integument of the bony fish.

Osteichthyes have vertebrae that enclose the spinal cord. Osteichthyes have amphicoelous vertebrae that allow for more movement. Since the vertebrae cannot restrict the amount of lateral movement, which would create a breaking in the fish’s vertebral column. A solution for this problem on an evolutionary path, were the intervertebral ligaments. These ligaments restrict the amount lateral movement conducted by the fish and increases the stiffening of the vertebrae. This also affects the limitation of lateral movement on the vertebral column. Another problem that comes up with the vertebral column being amphicoelous is that osteichthyes must deal with torque. To prevent this from happening, there are bands of connective tissue that act against the torque, produced by the fish swimming.

.          Gills on the osteichthyes have a bony flap that goes over their gills to protect them from the outside environment. This bony flap is called the operculum. It functions to open and close to create a current of water that goes through the gills, allowing the fish to breathe. This allows the osteichthyes to stay in place instead of moving towards a current of water to be pushed through the gills to breathe. Therefore, osteichthyes may remain stationary when breathing.

Reproduction:

           Osteichthyes reproduce once a year, in a process called spawning. There are 25,000 species of osteichthyes, many of which are a part of marine and freshwater ecosystems, giving a vast range of ways osteichthyes can reproduce. One way is when the female releases her eggs into the water while the male releases his sperm on top of the eggs, distributed by the female. This is very common way of spawning amongst osteichthyes. Another reproduction method occurs when the fish are hermaphrodites. These fish have both male and female reproductive organs and may change gender when there is a depletion of one gender within the species. This allows for a wide range of reproduction to occur as well as allow the fish to always have a partner for reproduction. An example of an osteichthyes that is a hermaphrodite is the Indo-Pacific cleaner wrasse, a marine specimen. Osteichthyes can also be viviparous, which allows the fish to have a direct line of supplements for their young to have the ability to operate autonomously without protection from others. An example of a viviparous osteichthyes is the scoliodon, another marine osteichthyes. The last way of reproduction is called oviparous similar to the viviparous method, but instead the eggs stay inside and do not have a direct line of supplements supplied to the eggs. Instead, eggs still contain yolk in which feed the embryo of the osteichthyes from. These eggs hatch inside the parent fish, then are later exposed to the outside environment. An example of an osteichthyes that does this is the comephorus.

Parental Care:

When osteichthyes have their offspring, they typically leave the larva or juvenile at the hatching site and allow the young to feed themselves. Sometimes, nearby parents will eat neighboring young to ensure their own young will survive. In some species, the parents wait for their young to grow out of the larval stage and protect their nests until after the larva have reached juvenile portions, then the parents leave. The transition from larva to juvenile takes about a 1-2 weeks for majority of osteichthyes.

Stages:

Most osteichthyes are hatched from eggs fertilized by sperm. The fish goes through a larval stage, where it is still connected the eggs yolk. At this point the osteichthye is called a fry, while nutrients are passed through connective tissue supplying necessary supplements.

The next stage is when the fry is no longer anchored to the yolk and begins to find microscopic food on its own. The fry becomes more independent and starts to eat zooplankton and krill, that are small yet packed full of nutrients, excellent for fish growth. As it continues to grow, the fish gets larger allowing for consumption of larger prey and/or plants.

References:

1.Fish Life Cycles - Province of Manitoba. https://gov.mb.ca/fish-wildlife/fish/fisheries_education_sustain_dev/education/outcomePages/grade2/pdf/fishcycle.pdf.

3.“Osteichthyes - Bony Fish: Wildlife Journal Junior - Wildlife Journal Junior.” New Hampshire PBS, https://nhpbs.org/wild/Osteichthyes.asp.

4.“Osteichthyes .” Osteichthyes, Fernbank Science Center, http://fsc.fernbank.edu/stt/vertbio/osteichthyes.htm.

5.“Osteichthyes.” Osteichthyes - an Overview | ScienceDirect Topics, https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/osteichthyes.