Phylum Chordata
Phylum Chordata is probably the most well-known of all the phyla, especially its major subphylum: subphylum Vertebrata. Elephants, jaguars, dogs, cats, elephants, giraffes, goats, sheep, deer, frogs, fish, sharks, lampreys, dolphins, birds, kangaroos, snakes, crocodiles, lizards, salamanders, gorillas, monkeys, rats, bats, and many, many more animals, including humans, belong to the subphylum Vertebrata. The main distinguishing features of chordates is that they have a notochord, which is a rod made up of certain cells that usually runs from head to tail in an organisms body, and all chordates have a body feature in their rear end that could possible make up a tail, called a post-anal tail. Now, humans don’t have a tail for their whole life, of course, but they could possibly possess one, and some newborns do have a tail-like feature because of this. Also, chordates are one of the more complex phyla, and contain the very most complex animals. Because of the fact that chordates can be so large, chordates vary a lot in size. The smallest chordate was recently discovered, called Oikopleura dioica. It is just a few millimeters wide. However, the blue whale, the largest animal on the planet that is extant, is also in the Phylum Chordata (They weigh about 200 tons, and a few have also been known to be almost 100 feet long. The record blue whale of all time measured about 110 feet long!).
Another feature that differs from chordate to chordate is food. While the blue whale slowly eats krill, the crocodile snatches bovids (cows, antelope, and goats) from out of the water. While the panda’s diet consists of solely bamboo, a human eats a wide variety of food in order to survive. There are known to be 3 subphyla of chordates: Subphylum Cephalochordata, Subphylum Tunicata, and Subphylum Vertebrata. However, there is some disagreement with Subphylum Vertebrata. Hagfish are very closely related to lampreys, but hagfish are invertebrates and lampreys are vertebrates. Subphylum Vertebrata basically means that its species have a backbone, but although hagfish don’t, they are much closer related to the animals in Vertebrata than the ones in Cephalochorata or Tunicata. So, for this reason, many scientists call this subphylum Craniata. Personally, I’m going to use just Vertebrata just to make it simpler, but just remember that when I’m talking about hagfish, they are really invertebrates. As stated at the beginning of this section, there are many animals in subphylum Cranita. They are usually simplified by common people into 5 groups: mammals, birds, reptiles, amphibians, and fish. Mammals, birds, and reptiles have lungs and breathe air, so therefore, most are terrestrial. Fish have gills and breathe water, so therefore, most are aquatic. However, there are some strange fish that actually breathe water and air. Amphibians for part of their life are like fish and for part are like mammals. They are born in water and have gills. Then, later in their life, their body transforms, and they move to the land, where they have lungs. Subphylum Tunicata contains tunicates, including sea squirts, and Subphylum Cephalochordata contains lancelets. Pretty much all chordates reproduce sexually except for some tunicates, which can either produce sexually or asexually.
Symmetry: Bilateral
Species Number: 65,000
Classification:
Kingdom Animalia
Eumetazoa
Bilateria
Phylum Chordata
Subphylum Cephalochordata (lancelets)
Class Leptocardii (lancelets)
Subphylum Tunicata (tunicates)
Class Appendicularia (larvaceans)
Class Ascidiacea (sea squirts)
Class Thaliacea (thaliaceans)
Subphylum Vertebrata (mammals, reptiles, amphibians, birds, and fish)
Class Agnatha (hagfish and lampreys: jawless fish)
Class Amphibia (frogs, salamanders and other amphibians)
Class Aves (birds)
Class Chondrichthyes (sharks, rays and other cartilaginous fish)
Class Mammalia (mammals)
Class Osteichthyes (bony fish: most well-known fish)
Class Reptilia (reptiles)
Heading Picture: African bush elephant (Loxodonta africana)
Subphylum Vertebrata (vertebrates: mammals, reptiles, amphibians, birds, and fish)
Class Mammalia (mammals)
Order Proboscidea (elephants and its extinct relatives)
Order Elephantidae (elephants)
Genus Loxodonta (African elephants)
Species Loxodonta africana (African bush elephant)
Another feature that differs from chordate to chordate is food. While the blue whale slowly eats krill, the crocodile snatches bovids (cows, antelope, and goats) from out of the water. While the panda’s diet consists of solely bamboo, a human eats a wide variety of food in order to survive. There are known to be 3 subphyla of chordates: Subphylum Cephalochordata, Subphylum Tunicata, and Subphylum Vertebrata. However, there is some disagreement with Subphylum Vertebrata. Hagfish are very closely related to lampreys, but hagfish are invertebrates and lampreys are vertebrates. Subphylum Vertebrata basically means that its species have a backbone, but although hagfish don’t, they are much closer related to the animals in Vertebrata than the ones in Cephalochorata or Tunicata. So, for this reason, many scientists call this subphylum Craniata. Personally, I’m going to use just Vertebrata just to make it simpler, but just remember that when I’m talking about hagfish, they are really invertebrates. As stated at the beginning of this section, there are many animals in subphylum Cranita. They are usually simplified by common people into 5 groups: mammals, birds, reptiles, amphibians, and fish. Mammals, birds, and reptiles have lungs and breathe air, so therefore, most are terrestrial. Fish have gills and breathe water, so therefore, most are aquatic. However, there are some strange fish that actually breathe water and air. Amphibians for part of their life are like fish and for part are like mammals. They are born in water and have gills. Then, later in their life, their body transforms, and they move to the land, where they have lungs. Subphylum Tunicata contains tunicates, including sea squirts, and Subphylum Cephalochordata contains lancelets. Pretty much all chordates reproduce sexually except for some tunicates, which can either produce sexually or asexually.
Symmetry: Bilateral
Species Number: 65,000
Classification:
Kingdom Animalia
Eumetazoa
Bilateria
Phylum Chordata
Subphylum Cephalochordata (lancelets)
Class Leptocardii (lancelets)
Subphylum Tunicata (tunicates)
Class Appendicularia (larvaceans)
Class Ascidiacea (sea squirts)
Class Thaliacea (thaliaceans)
Subphylum Vertebrata (mammals, reptiles, amphibians, birds, and fish)
Class Agnatha (hagfish and lampreys: jawless fish)
Class Amphibia (frogs, salamanders and other amphibians)
Class Aves (birds)
Class Chondrichthyes (sharks, rays and other cartilaginous fish)
Class Mammalia (mammals)
Class Osteichthyes (bony fish: most well-known fish)
Class Reptilia (reptiles)
Heading Picture: African bush elephant (Loxodonta africana)
Subphylum Vertebrata (vertebrates: mammals, reptiles, amphibians, birds, and fish)
Class Mammalia (mammals)
Order Proboscidea (elephants and its extinct relatives)
Order Elephantidae (elephants)
Genus Loxodonta (African elephants)
Species Loxodonta africana (African bush elephant)