Fish Classification and Characteristics PDF

CLASS: FISHES (PISCES, OSTEICHTHYES) Ryby CHARACTERISTICS ICHTYS (Greek for fish) - The most numerous group of all vertebrates, live in all types of water ecosystems - Have hydrodynamic shape - their body is streamlined and flattened sideways SKIN - Covered by slime and scales...

CLASS: FISHES (PISCES, OSTEICHTHYES) Ryby CHARACTERISTICS ICHTYS (Greek for fish) - The most numerous group of all vertebrates, live in all types of water ecosystems - Have hydrodynamic shape - their body is streamlined and flattened sideways SKIN - Covered by slime and scales - Scales are derivatives of skin – grow from cavities in the skin - Scales grow throughout the life of fish and form growth rings - Melanophores- cells that contain pigment – melanin TYPES OF SCALES I. CYCLOID – circular and smooth (carp) II. CTENOID – with small projections (perch) III. GANOID – rhomboid (sterlet) SKELETAL SYSTEM - Fins are supported by spines - Bony skeleton (exc. Sterlet) - Skeleton is divided into 3 parts: - Skull (head) - Spine - fins SPINE - made of vertebrae - notochord is reduced into intervertebral discs - ribs are attached to frontal vertebrates FISH FINS MUSCULAR SYSTEM Muscles in segments DIGESTIVE SYSTEM - Simple digestive system - Mouth → pharynx→ oesphagus→ stomach → intestine → anal pore - Carps: have small teeth in oesophagus - The liver secretes bile and pancreas secretes digestive enzymes - Oesophagus extends into a swim bladder filled with gases (O2, N2, CO2) enables fish to float and sink in water RESPIRATORY SYSTEM Bony Gill Arches: These are the supports that hold the gills in place. Gill Filaments: These are thin, feather-like structures attached to the gill arches. They have a large surface area to allow for efficient gas exchange. Gill Rakers: are comb-like projections attached to the gill arches. Their role is to filter food particles and debris from the water before it passes over the gill filaments Operculum: This is a bony flap that covers and protects the gills BREATHING - The fish opens its mouth and takes in water. - The water flows over the gill filaments, which are attached to the bony gill arches. - Oxygen from the water is absorbed into the blood through the thin walls of the gill filaments. - Carbon dioxide from the fish’s blood is released into the water through the gill filaments. - The water, now depleted of oxygen, exits the fish through the gill slits behind the operculum CIRCULATORY SYSTEM - Closed - Ectotherms - The fish circulatory system consists of a two-chambered heart (atrium and ventricle) CIRCULATORY SYSTEM - heart pumps deoxygenated blood to the gills. - In the gills, blood is oxygenated and then transported throughout the body via arteries, delivering oxygen to tissues and collecting carbon dioxide. - The deoxygenated blood returns to the heart through veins, completing the single-loop circuit. EXCRETORY SYSTEM - Have kidney which filter waste products from the blood NERVOUS SYSTEM -The nervous system of fish includes the brain, spinal cord, and nerves. - The brain is divided into several parts: Forebrain : Includes the olfactory bulbs (detects smells) and the cerebrum (handles complex behaviors and sensory processing). Diencephalon: Processes sensory information and regulates homeostasis. Midbrain : processes visual information Hindbrain: Consists of the cerebellum (coordinates movement and balance) and the medulla oblongata (controls basic life functions like respiration and heart rate). FISH EYES - Fish eyes are well-adapted to underwater vision, allowing them to detect light, movement, and color. Nostrils are used for smelling, helping fish detect chemicals and scents in the water.  Barbels - are whisker-like structures near the mouth that contain taste buds and touch receptors Lateral Line: This is a sensory organ running along the sides of the fish's body, detecting vibrations and pressure changes in the water, helping fish sense movement and nearby objects. REPRODUCTIVE SYSTEM - Are Gonochorists - External Fertilization (spawning) the female releases eggs into the water and the male spreads cloud of sperm over the eggs, leading to fertilization outside the body. - Eggs – spawn (caviar) - Milt- seminal fluid REPRODUCTIVE SYSTEM - The fertilized eggs hatch into yolk-sac larvae, which are equipped with a yolk sac for nourishment until they can feed independently. Anadromous Fish: These fish, such as salmon, are born in freshwater, migrate to the ocean to grow, and return to freshwater to spawn. Catadromous Fish: These fish, such as eels, live in freshwater but migrate to the ocean to spawn. CLASSIFICATION I. subclass: lobe-finned fishes II. subclass: ray-finned fishes I. SUBCLASS: LOBE-FINNED FISHES - typically found in deep marine environments - Coelacanths are considered "living fossils" because they have remained relatively unchanged for about 400 million years. - lobed fin structure that is believed to be an evolutionary link between fish and the early vertebrates that moved onto land. - were thought to be extinct but were spotted to exist Species: Ocean coelacanth (latiméria divná) 2. Lungfishes (dvojdyšníky) - live in freshwater - There are six extant species of lungfish, - have both gills for underwater breathing and a lung-like structure for aerial respiration. - The lung allows it to breathe air when oxygen levels in the water are low 2. Lungfishes (dvojdyšníky) · Australian lungfish (bahník austrálsky) · South American lungfish (bahník americký) · West African lungfish (bahník africký) II. SUBCLASS: RAY-FINNED FISHES (LÚČOPLUTVOVCE) - Most of the fishes belong there - Marine/freshwater - Fins are further supported with cartilages or bony structures (rays) STERLET - JESETER Common carp – kapor obyčajný Bream – pleskáč vysoký Prussian carp – karas striebristý Common barbel – mrena severná Tench – lieň sliznatý European perch – ostriež riečny Northern pike - šťuka obyčajná Pikeperch – zubáč obyčajný European catfish – sumec západný The european eel – úhor európsky Roach – plotica Atlantic bluefin tuna – tuniak atlantický Atlantic cod – treska atlantická Atlantic herring – sleď obyčajný ATLANTIC SALMON Interesting fishes flying fishes artist hunters VOCABULARY: ★ CYCLOID SCALES ★ CTENOID SCALES ★ GANOID SCALES ★ SWIM BLADDER ★ OPERCULUM ★ BARBELS ★ LATERAL LINE ★ SPAWN ★ MILT ★ EXTERNAL FERTILISATION ★ CATADROMOUS FISH ★ · ANADROMOUS FISH REVISION What are three types of scales? Skeletal system of fish is divided into? Name fins of the fish. Describe digestive system of the fish. How do fish breath? How does circulatory system of fish work like? How is fish brain divided? REVISION Describe fish sensory organs. What do you know about the reproductive system of fish? What's the difference between catadromous fish and anadromous fish? What are 2 subclasses of fishes? What's the characteristics they have different? Compare lobe-finned fishes and lungfishes. Name 10 species of freshwater fishes. Name species of marine fishes.