ZOOLOGY STUDY GUIDE - Ye. O. Nevedomska - 2013

LECTURE 14. INFRAPHYLUM GNATHOSTOMATA. SUPERCLASS PISCES

It is interesting to know that

- The saying "as mute as a fish" is far from the truth. Fish produce a variety of sounds that are perceived by members of the same or other species as signals with specific meanings

1. spawning signals — attracting members of the opposite sex, recognition, and stimulation of gamete release;

2. warning and threat signals when defending spawned eggs or guarding their territory.

Sounds are produced by: friction of fin rays, jaw bones, and the operculum, the Pectoral Girdle, or the swim bladder and specialized Muscles surrounding it.

- An eviscerated shark can not only swim normally but also strike at prey and swallow it.

- The ancestor of the aquarium goldfish was the Prussian carp. The goldfish was bred through long-term selective breeding in China. The first mentions of it date back to the first century BC.

- In the UK, there are factories that manufacture clothing from fish Skin. Salmon, shark, and ray skins are used to make belts, bags, wallets, purses, and even jackets and skirts. This clothing and leather goods are in high demand. Manufacturers claim that fish leather resembles suede, is highly durable, and has absolutely no fishy odor.

- Small marine fish swim in schools that resemble a drop of Water. How can this be explained? This minimizes the resistance of the aquatic medium. In addition, the schooling lifestyle of small

fish offers other advantages: it is much harder for a predator to approach a school undetected than a single fish; even snatching a fish from a school is more difficult, as it is hard to single out one target from among so many.

- So-called flying fish do not actually have wings. How do they fly then? Flying fish, which live near the water surface in all tropical seas, are capable of short-term flight. They launch into the air with the help of a powerful caudal fin. First, the fish accelerates along the water surface (reaching speeds of 65 km/h), and then a powerful stroke of the caudal fin lifts it into the air. Its outspread, massive pectoral fins support the fish's body like the wings of an airplane. The fish's flight occurs solely due to inertia. Inertia (meaning "inactivity, laziness") is the phenomenon where a body maintains its velocity when no other forces act upon it. Their typical flight distance is several dozen meters, but they can sometimes glide up to 400 m.

- Why does a fish suffocate when taken out of water, even though there is much more oxygen in the air than in the water? Only oxygen dissolved in water can diffuse into the Blood, whereas in the air, the fish's gill filaments stick together, drastically reducing the respiratory surface area.

- When threatened by a predator, the porcupinefish turns into a spiny ball. How does it manage this? Under threat, the porcupinefish swallows air and passes it into its digestive tract. Because of this, it inflates, turning into a spiny ball, and its density decreases. Density is a physical quantity equal to The ratio of a body's mass to its volume. The fish floats on the water's surface belly up, with part of its body protruding above the water. In this state, it is protected from danger both from above and below.

FROM THE HISTORY of Science

- The "Placenta" of sharks was first described by Aristotle (4th century BC).

Evolutionary Process

- Scientists believe that the ancestors of fish were primitive lancelets (Acrania), which did not closely resemble fish. They lacked paired fins, a true HEAD and Brain, developed Sensory Organs, Teeth, jaws, and many other features characteristic of modern fish. This is not surprising, since various hypotheses propose Annelids, Arthropods, or Echinoderms as the ancestors of fish. The divergence of these hypotheses is also not particularly surprising, as it remains unclear whether fish originally originated in marine saltwater or freshwater.

- It is believed that true fish-like vertebrates appeared about 440 million years ago. Their first fossil remains were discovered in deposits from the late Ordovician to early Silurian. They did not yet possess jaws, a crucial feature for fish, but they already had a cartilaginous and dense exoskeleton in the form of armor or small plates on the anterior part of

the body, a scaled caudal region, and some even had fin-like structures. Based on the combination of their known characteristics, they were named jawless armored fish-like vertebrates — Agnatha.

Interesting Facts About THE ORIGIN OF Fish Names

- The perch (okun) is essentially a "big-eyed" fish, as its most prominent feature is its large eyes. Its Ukrainian name is derived from the word "oko" (eye) with the suffix "-un", which has long since disappeared from active "living" suffixes.

- Shark (Akula). Scientists believe that this name for the "hyena of the sea" came long ago from Old Norse: the Norsemen called this fish "hákarl". In our language, this word acquired the ending "-a" because most fish names have it: "syomg-a" (salmon), "gorbush-a" (pink salmon), "shchuk-a" (pike), "trisk-a" (cod), "vobl-a" (Caspian roach), "plitk-a" (roach). The word "ryb-a" (fish) itself might have also had an influence.

Enjoy your meal!

- Throughout history, without exception, caviar has served not only as a symbol of prosperity but also as one of the most delicious and exquisite seafood delicacies. This delicacy is well known to be highly beneficial to The Human Body. Since fish eggs are destined to develop into a new Organism, they contain a unique profile of nutrients and BIOLOGICALLY ACTIVE SUBSTANCES. First and foremost, it is rich in protein—containing 32 g per 100 g—which is absorbed rapidly, within just an hour. Furthermore, this protein features a complete profile of both essential and non-Essential Amino Acids. Consequently, consuming caviar provides an immediate boost of energy. So, revitalize your body and restore your energy with caviar!