Subphyla Vertebrata and Classes
Vertebrates
are animals with a spinal column which runs from the head to the tail bone. The
presence of a backbone has led to classes of animals with complex circulatory
system, advanced nervous systems and acute sensory organs.
Myxini
The
most basal group to craniates (Chordatas with heads), Myxini are commonly
referred to as the hagfishes. They have a skull made from cartilage, but lack a
jaw or vertebrae. They move similarly to snakes, forcing their segmented
muscles against their notochord to glide through the sea. Hagfish produce slime,
which is used to repulse competitors or predators. An example is the pacific hagfish.
|
Cephalaspidomorphi
Known
as the lampreys, they are the most basal group to all living vertebrates. They have
a round, jawless mouth which is commonly used to latch onto other fish in a
parasitic manner. As larvae, they reside in freshwater streams and feed through
suspension. When older, they move to seas or lakes. Their skeletons are made of
cartilage. An example is the European river lamprey.
|
Chondrichthyes
Comprised
of sharks, rays and their relatives, Chondrichthyans include the biggest
predators of the oceans. Their skeletons are composed of primarily cartilage
and their bodies are streamlined. They are swift swimmers and must continuously
move, otherwise they will sink. Gas exchange occurs as water flows into the
mouth and out the gills. They have acute senses, from strong eye vision to
having the ability to detect electrical fields generated by muscle movement of
nearby organisms. An example is the gray reef shark.
|
Osteichthyes
Known
informally as just fishes, Osteichthyans have skeletons that are bony with a
hard matric of calcium phosphate. Fish breathe by drawing water through their
gills. They control their buoyancy with a swim bladder. Gas from the blood enters
the swim bladder, increasing buoyancy while the reverse decreases buoyancy. The
skin is covered in flattened, bony scales and mucus, which reduces drag during
swimming. An example is the red lion fish.
|
Amphibia
Amphibians
live in damp environments, using their moist skin for gas exchange. Amphibians
begin their lives solely in the water, eventually maturing and being able to
live in both the water and land. Made up of salamanders, frogs and apodans,
amphibians have a diverse range of locomotion capabilities. An example is the red eyed tree frog.
|
Reptilia
A
unique class, reptiles have several features which differ from other tetrapods.
They usually lay hard-shelled eggs on land, which are fertilized internally. Reptiles
have scales made from keratin, for protection against predators and the
environment. Most reptiles, except for birds, are ectothermic. They devote very
little metabolism to maintaining their body temperatures and rely on the shade
or sun instead. An example is the red eared slider.
|
Aves
Commonly
known as birds, Aves are mostly adapted for life in the sky. Feathers, hollow
and light bones, large pectoral muscles, elastic air sacs, endothermic
metabolism and a four-chambered heart all allow birds to fly. Their
flight conveys many advantages, from migration of long distances to escape from
predators. Birds display complex behavior, especially during the mating season.
An example is the peregrine falcon.
|
Mammalia
An
amniotic lineage like the reptiles, mammals have several unique traits of their
own. The most distinctive is the presence of mammary glands, which provide milk
for the offspring. Fat layers under the skin and hair on top of the skin helps
to retain heat. Mammals are endothermic, with high metabolism rates. Such high
metabolism is supported by efficient respiratory and circulatory systems. Most
importantly, mammals have larger brains in comparison to other vertebrates of
equivalent size, making them fast and capable learners. An example is the domestic goat.
|
Click on the following link to learn about the Kingdom Fungi: