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Over 97% of all known fish are oviparous, [74] that is, the eggs develop outside the mother's body. Examples of oviparous fish include salmon , goldfish , cichlids , tuna , and eels . In the majority of these species, fertilisation takes place outside the mother's body, with the male and female fish shedding their gametes into the surrounding ...
In species like the spiny dogfish and other sharks and rays, a spiracle exists near the top of the head that pumps water into the gills when the animal is not in motion. [5] In some fish, capillary blood flows in the opposite direction to the water, causing countercurrent exchange .
Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.
Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills that are protected under gill covers (operculum) on both sides of the pharynx (throat). Gills are tissues that are like short threads, protein structures called filaments. These filaments have many functions including ...
The lung has a single opening on the right side, called the pneumostome, which either remains permanently open, or opens and closes as the animal breathes. The roof of the lung is highly vascularised, and it is through this surface that gas exchange occurs. The majority of pulmonates are fully terrestrial.
The extraembryonic membranes are four membranes which assist in the development of an animal's embryo. Such membranes occur in a range of animals from humans to insects. They originate from the zygote, but are not considered part of the embryo. They typically perform roles in nutrition, gas exchange and waste removal. [1]
In the second part, the person in the video cracks an egg open into the liquid and the content solidifies very quickly as you can see after it's taken out. WATCH: See how a GoPro handles a torture ...
Various fish, as well as polychaete worms and even crabs, are specialized to take advantage of the constant flow of water through the cloacal respiratory tree of sea cucumbers while simultaneously gaining the protection of living within the sea cucumber itself. At night, many of these species emerge from the anus of the sea cucumber in search ...