The Animal Kingdom
There are nine phyla in Kingdom Animaelia. Eight of these nine phyla consist of invertebrates. The invertebrates are:
- Porifera (sponges)
These were the first to evolve. They are very simple organisms with no circulatory, respritory, or nervous systems. They reproduce mostly asexually and
cannot move.
- Cnidaria (cnidarians)
These are the second simplest organisms after the Porifera and have no circulatory systems or respritory systems. However, they have simple nervous systems called "nerve nets" and can move. They reproduce both sexually and asexually. They have one opening.
- Platyhelminthes (flatworms)
Many flatworms are parasitic, such as tapeworms. They are the first to have both a head and a tail. They have one opening and produce sexually and asexually. They have nervous systems somewhat more complex than those of the cnidarians, consisting of a nerve cord, eye spots, and a very simple brain.
- Nematoda (roundworms)
One half of all roundworms are parasitic. They have a simple nervous system but still no circulatory or respritory systems. They have two openings, both a mouth and an anus, and reproduce sexually.
- Annelida (segmented worms)
Like all worms, the annelida have bilateral symmetry. Segmented worms such as leeches and earthworms have complex organ systems and move using setae. They reproduce sexually and have closed circulatory systems. They are the most complex of the worms.
- Mollusca (mollusks)
This phylum includes clams and octopi. They are complex organisms with bilateral symmetry. They reproduce sexually and have full respritory, nervous, and circulatory systems. Octopi have fully developed brains.
- Echinodermata (echinoderm)
Echinoderms have five-part radial symmetry. Starfish and seacucumbers are two examples of this phyla. They are either male or female rather than hermarphroditic like most previous animals were. They are solely marine animals. They have no brain and a poorly developed nevous system. They have water-vascular circulatory systems and respirate through tube feet and gill structures.
- Arthrophoda (arthropods)
Insects and crabs are arthropods. They make up 75-80% of all animals and have segmented bodies. They go through metamorphisis while cyhanging. They have exoskeletons which they molt as they grow and jointed appendages. They reproduce sexually, use gills, book lungs, and tracheal tubes for respiration, and have open circulatory systems.
- Chordata (vertebrates)
Mammals, birds, reptiles, and other vertebrates fall into the phyla Chordata. They are the most complex animals. All chordata reproduce sexually, and the different types use a variety of different means for respiration. All have complex circulatory systems.
Vampyroteuthis infernalis, Vampire Squid
The vampire squid belongs to the phylum Mollusca, and is an invertebrate. They live at lightless depths of the ocean (between 600-900 metres below). Most organisms cannot reside at these levels because the oxygen level is extremely low. Very little is known about the vampire squid's eating habits. However, copepods, prawns, and cnidarians are all known prey. Their muscles are very weak because of the low oxygen levels (and therefore low metabolic levels) of their environments, so their movements are rapid but cannot continue for long due to low stamina. They also use jet propulsion to project forwards. Little is known about their reproductive habits. However, biologists can assume due to the knowledge of the reproductive habits of other cephalopods and deep-sea creatures that they probably reproduce very slowly and with few eggs at a time.
Interestingly enough, Vampire Squids do not possess ink sacs like many other cephalopods do. Instead of ejecting a black ink like most cephalopods do, they eject something which may appear at first to be counterintuitive: a bright, bioluminescent mucus. This aids the squid's escape because animals at these depths are not used to any sort of light, so the attacker is temporarily dazed, and the squid can flee into the darkness.
Interestingly enough, Vampire Squids do not possess ink sacs like many other cephalopods do. Instead of ejecting a black ink like most cephalopods do, they eject something which may appear at first to be counterintuitive: a bright, bioluminescent mucus. This aids the squid's escape because animals at these depths are not used to any sort of light, so the attacker is temporarily dazed, and the squid can flee into the darkness.
