Infraphyla / Classes
Class Actinopterygii
Actinopterygii is a large class that contains over 20,000 species. A well-known member of this class is the lionfish. Like members of Class Sarcopterygii, they have a bony skull and vertebrae. Their fins are paired but lack muscular lobes. They have a bony operculum that covers their gill opening and they have a swim bladder as well as scales and jaws. Members of this class excel at adapting to different environments. They are arguably the most successful group of fish because they are extremely deadly predators thanks to their efficient respiratory systems, good swimming skills, powerful sensory system, and a strong skeletal system. Ray-finned fishes are the dominant aquatic vertebrates and can be found in every aquatic habitat. Some are even capable of crawling on land.
Source(s): http://www.ucmp.berkeley.edu/vertebrates/actinopterygii/actinintro.html, Edmodo notes
Actinopterygii is a large class that contains over 20,000 species. A well-known member of this class is the lionfish. Like members of Class Sarcopterygii, they have a bony skull and vertebrae. Their fins are paired but lack muscular lobes. They have a bony operculum that covers their gill opening and they have a swim bladder as well as scales and jaws. Members of this class excel at adapting to different environments. They are arguably the most successful group of fish because they are extremely deadly predators thanks to their efficient respiratory systems, good swimming skills, powerful sensory system, and a strong skeletal system. Ray-finned fishes are the dominant aquatic vertebrates and can be found in every aquatic habitat. Some are even capable of crawling on land.
Source(s): http://www.ucmp.berkeley.edu/vertebrates/actinopterygii/actinintro.html, Edmodo notes
Class Chondrichthyes
This class is home to the shark as well as rays and skates, but the shark is arguably the most well-known member of this class. Sharks are one of the most dangerous predators of the ocean and are at the top or the near the top of the food chain. Sharks are extremely important to the ecosystems of the oceans because they help keep populations of species below them under control. There about 465 species of shark. Sharks are cartilaginous and have a skull and vertebrae. Sharks have extremely powerful jaws and have paired fins as well as a caudal fin. They lack an operculum over their gills and they are mostly marine. Members of this class are mostly predators and scavengers but the whale shark is a filter feeder.
Source(s): http://www.defenders.org/sharks/basic-facts, Edmodo notes
This class is home to the shark as well as rays and skates, but the shark is arguably the most well-known member of this class. Sharks are one of the most dangerous predators of the ocean and are at the top or the near the top of the food chain. Sharks are extremely important to the ecosystems of the oceans because they help keep populations of species below them under control. There about 465 species of shark. Sharks are cartilaginous and have a skull and vertebrae. Sharks have extremely powerful jaws and have paired fins as well as a caudal fin. They lack an operculum over their gills and they are mostly marine. Members of this class are mostly predators and scavengers but the whale shark is a filter feeder.
Source(s): http://www.defenders.org/sharks/basic-facts, Edmodo notes
Class Petromyzontida
Lampreys, unlike hagfishes, have a vertebrae that surrounds their nerve cord. They also have a skull made of cartilage. Much like hagfishes, they are jawless and lack paired fins but lampreys have two dorsal fins and a caudal fin. They use their mouths to grab on to prey and feed on the body fluids. This makes lampreys parasitic and predator-like. Fish with lampreys attached to them can become severely weakened and even killed. They can be found in both marine and freshwater environments where it's temperate. Fossils of lampreys are extremely rare and hard to find. But judging from what has been recovered, lampreys have not changed too much over the 300 million years of their existence.
Source(s): http://www.ucmp.berkeley.edu/vertebrates/basalfish/petro.html, Edmodo notes
Lampreys, unlike hagfishes, have a vertebrae that surrounds their nerve cord. They also have a skull made of cartilage. Much like hagfishes, they are jawless and lack paired fins but lampreys have two dorsal fins and a caudal fin. They use their mouths to grab on to prey and feed on the body fluids. This makes lampreys parasitic and predator-like. Fish with lampreys attached to them can become severely weakened and even killed. They can be found in both marine and freshwater environments where it's temperate. Fossils of lampreys are extremely rare and hard to find. But judging from what has been recovered, lampreys have not changed too much over the 300 million years of their existence.
Source(s): http://www.ucmp.berkeley.edu/vertebrates/basalfish/petro.html, Edmodo notes
Class Sarcopterygii
Lobe-finned fish are the most recent ancestors of amphibians. They have a bony skull and vertebrae as well as a bony operculum that covers their gills. Their paired fins are attached to muscular lobes. Lobe-finned fishes have scales as well as jaws. Two groups of fish represent this class: the coelacanths and the lungfish. Lungfish lack a swim bladder but have lungs. Lungfish prefer to live in shallow waters. Coelacanths are ancient and have not changed much over time. They have a swim bladder and live in open waters. Lobe-finned fishes are often considered one of the most successful groups of vertebrates. They were very successful during the Paleozoic Era and were very diverse and were one of the top predators in their marine and freshwater habitats during the Devonian and Carboniferous Eras.
Source(s): http://www.devoniantimes.org/who/pages/lobe-fins.html, Edmodo notes
Lobe-finned fish are the most recent ancestors of amphibians. They have a bony skull and vertebrae as well as a bony operculum that covers their gills. Their paired fins are attached to muscular lobes. Lobe-finned fishes have scales as well as jaws. Two groups of fish represent this class: the coelacanths and the lungfish. Lungfish lack a swim bladder but have lungs. Lungfish prefer to live in shallow waters. Coelacanths are ancient and have not changed much over time. They have a swim bladder and live in open waters. Lobe-finned fishes are often considered one of the most successful groups of vertebrates. They were very successful during the Paleozoic Era and were very diverse and were one of the top predators in their marine and freshwater habitats during the Devonian and Carboniferous Eras.
Source(s): http://www.devoniantimes.org/who/pages/lobe-fins.html, Edmodo notes
Infraphylum Hyperotreti
Hagfishes are jawless invertebrates (their notochord made of cartilage supports their bodies). Their skulls are made of cartilage and they have no paired fins. Hagfishes have glands inside their skin that allow them to secrete mucus which helps protect them against predators. They prefer cold-water habitats and are found in marine environments. Hagfishes are not predators, but rather scavengers.
Source(s): http://www.smithsonianmag.com/science-nature/14-fun-facts-about-hagfish-77165589/?no-ist, Edmodo notes
Hagfishes are jawless invertebrates (their notochord made of cartilage supports their bodies). Their skulls are made of cartilage and they have no paired fins. Hagfishes have glands inside their skin that allow them to secrete mucus which helps protect them against predators. They prefer cold-water habitats and are found in marine environments. Hagfishes are not predators, but rather scavengers.
Source(s): http://www.smithsonianmag.com/science-nature/14-fun-facts-about-hagfish-77165589/?no-ist, Edmodo notes
Representative organism: Basking Shark
- Class: Chondrichthyes
- Scientific name: Cetorhinus maximus
- They are filter feeders
- Basking sharks have hundreds of teeth, but they aren't very useful
- Basking sharks travel alone, in pairs, or in groups with up to 100 members
- They can grow to be up to 33 feet long and they are the second-largest shark (the whale shark is the largest)
- They can weight up to 4 tons
- Their colors vary: they can be grayish brown to black to bluish on their surface and their bellies are usually white or darker
- Basking sharks eat very small animals, such as plankton, small fish, and fish eggs
- Basking sharks live near coastal temperate waters
Source(s): http://www.enchantedlearning.com/subjects/sharks/species/Baskingshark.shtml