- Animal Diversity
Animals are placed by scientists into taxonomic categories based upon their similar characteristics. We will briefly at the phyla of the animal kingdom.Animal Phyla
Porifera: This phylum contains the sponges. Although they may not seem much like animals, they do obtains their food through specialized collar cells. Sponges do not have tissues or organs and are said to be at the “cellular level” of development.
Cnideria: This phylum contains the jellyfish and the sea anemones. These organisms have tissues and specialized organs (stinging organs) called nematocysts. They have a fluid filled body cavity that acts as a hydrostatic skeleton.
Platyhelminthes: These are the flat worms. They are at the organ system level or development and actually show cephalization or the development of a head region. Although these are more advanced than the jellyfish, they do not have a complete digestive system. The Planaria and the tape worms belong to this phylum.
Ascaris (roundworm) dissection - The dissection images are from WKU's Bio 225, Zoology class.Click the images to see more, but the material is not really part of Bio 113.
These include Wuchereria bancrofti that causes elephantiasis, pin worms, and the blood flukes. Personally, this is the group I would like to avoid!
Rotifera: These are small animals that live in lakes and ponds. They eat bacteria and algae.
Molluscus: This is a fascinating group of organisms that contains the snails, slugs, oysters, clams and squid. These animals have soft unsegmented bodies that are sometimes enclosed by a shell that is secreted by a mantle. Some of these organisms have 2 shells (bivalves) like the oyster, while others have a head region (cephalopods) like the squid. These organisms have a foot ( a muscular organ for motility) and a heart!
Annelids: This phylum includes the segmented worms such as earthworms and leeches. This group has a closed circulatory system and a primitive brain! So earthworms are fairly advanced compared to sponges!
Lumbricus (earthworm) dissection
Arthropoda: This is the largest of all the animal phyla. It is so large that we will look at 3 classes under arthropoda. This phyla contains animals that have a chitinous exoskeleton, a segmented body, and paired, jointed appendages.Classes
Arachnids: This class includes the spiders and ticks. This is another of my personal least favorite creatures. These have 4 pairs of legs and a pair of chelicerae that cause wounds and inject venom. They contain spinnerets that produce silk.
Crustacae: This class contains the crayfish and lobsters. These have a carapace to protect the gills, a fused cephalothorax, and an abdomen with a fanned tail. The first pair of walking legs is modified into enlarged pinchers.
Insecta: This is a very large class of organisms! These have a head, a thorax (with 3 pairs of walking legs) and an abdomen. These organisms have specialized mouthparts for sponging, sucking, piercing, biting, etc.
Echinoderms: This is an “odd-ball” phylum where a curious group of organisms are grouped. These include the sand dollars, sea urchins and star fish. These do not have a brain but do contain numerous calcium-containing spicules. They also have a unique water vascular system.
Perca (Perch) dissection
Fish: Aquatic organisms that have a backbone or cartilage or bone. They have gills and skull bones to protect the brain.
Amphibians: These are the organisms that have made the transition to land. These include the salamanders, frogs and toads. The temperature of their bodies does fluctuate with the temperature of the environment. Although these can live on land, there is a requirement for water at some time in the life cycle.
Reptiles: These organisms have internalized reproduction so that there is less of a requirement for water. They include the turtles, lizards, snakes and crocodiles.
Birds: These are the animals that are adapted for flight. They are light weight, have a unique respiratory system, feathers and flight muscles.
Mammals: This group of organisms nourish their young with milk, have hair, have specialized teeth, and cannot adjust their body temperature. There are 3 groups of these:
· Egg-layers: These do not have teeth. They include the spiny anteater and the duck-billed platypus.
· Pouched (marsupials): These include the kangaroos and carry their young in a pouch.
· Placental: These develop in the mother’s uterus until birth