Animal Kingdom General Characteristics:

• All organisms are eukaryotic.

• They are all multicellular.

• Their cells have no cell walls. 

• They are heterotrophic.

Phylum Porifera (Sponge)

• Simplest multicellular animals.

• Habitats: marine habitats and a few are in fresh water. 

• Have pores all over the body.

• Have a canal system that helps in circulating water and food particles and oxygen. 

• The body design shows minimal differentiation and division of tissues.

• Examples: Spongilla and Sycon.

• Reproduction: sexually and asexually by budding and fragmentation.

Phylum Cnidarians

• These organisms show more body differentiation.

• They live in water.

• The body has a sac-like cavity with a single opening for ingestion and Egestion

• Cnidarians have a unique feature: stinging cells called cnidocytes. 

• Have the ability to reorganize and regenerate their bodies 

• Examples: Jellyfish, Sea Anemone, and Hydra.

Phylum Platyhelminthes (flatworms)

• They are a group of soft-bodied invertebrate animals.

• Around 20,000 species of these animals.

• A few of these live as parasites on humans and other animals. So they do cause some amount of trouble for the host animal. 

• A few species can be a major cause of certain diseases. For example bilharzia, a disease caused by these parasitic flatworms. 

• As the body does not have any cavity, they are flat. The body is also not segmented and they do not have specialized systems

• The animals in this phylum have a diverse range in size. Some are microscopic, while a few go up to two feet long.

• They are also hermaphrodites, which mean that both sexes are present in the same organism.

• Reproduction: sexually by fusion of gametes and asexually by fission and regeneration.

Phylum Nematoda (roundworms)

• Are very abundant. It has more than 80,000 known species. 

• Are bilaterally symmetrical.

• Their body plan is simple. 

• Surrounded by a strong, flexible non-cellular layer called a cuticle. The cuticle is secreted by and covers a layer of epidermal cells.

• Near the body wall but under the epidermal cells are muscle cells; they run in the longitudinal direction only. A true coelom (main body cavity ) Nematodes move by contraction of the longitudinal muscles. No cilia or flagella are present.

• They reproduce sexually by sperm and eggs by male and female adults

• Free-living worms are found mainly in freshwater habitats. Some live in soil, food, and humans.

• They Feed on bacteria, fungi, protozoans, or decaying organic matter.

• By breaking down organic matter, they play an important role in the carbon cycle.

Phylum Annelida (ringed worms)

• Over 17,000 species.

• Exist in marine waters, fresh waters, and also in moist terrestrial areas.

• The size of the annelids can range from a few millimeters to three meters in length.

• The Australian earthworm measures around 3 meters. 

• Annelids exhibit bilateral symmetry and are invertebrate organisms.

• Reproduction: sexual and asexual (Some have female, and male organs).

• Examples: Leeches, Earthworms, and bobbit worms.

Phylum Arthropoda

• Over 85 percent of all known animal species are arthropods.

• The body is divided into the head, thorax, and abdomen.

• Joint-legged animals include insects, spiders, ants, bees, crabs, shrimps, etc.

• Are successful in the wild because of their exoskeleton. It gives them flexibility, mobility, and protection.

• Live on land and water.

• They’re a source of food for many animals and human beings.

• Reproduction: sexual

• Major classes compare the number of body regions, legs, and antennae.

Phylum Mollusca

• Many have a calciferous shell. 

• Invertebrates, with bodies very soft and are covered by the hard exoskeleton.

• Can be found in terrestrial regions and in the depths of the sea

• Size can range from 20 meters to one millimeter, with a few microscopic animals too. 

• They are a source of food as well as jewelry.

• Pearls that are obtained from bivalves and gastropods are valuable as these pearls are lined with nacre. 

• Reproduction: sexual

• Organ level of organization.

• Examples can be snails, slugs and oysters.

Phylum Echinodermata(sea stars)

• They have a star-like appearance and are spherical or elongated.

• They are exclusively marine animals.

• Are spiny-skinned.

• Organ system level of organization. Most members have a circulatory system as well as a digestive system.

• They respire through the gills

• The body is unsegmented with no distinct head.

• The mouth is present on the ventral side while the anus is on the dorsal side.

• The tube feet aid in locomotion.

• Fertilization is external. 

• Reproduction: sexual and asexual

Phylum Protochordata

• They are generally found in marine water.

• Their body is bilaterally symmetrical, triploblastic, and coelomated.

• Lack a head, skull, vertebral column, and brain.

• Organ system level of organization.

Phylum Vertebrata

Mammals (Class Mammalia)

• Ability to regulate their body temperature irrespective of the surrounding ambient temperature. (endothermic)

• Female mammals produce milk. 

• Almost all mammals give birth.

Birds (Class Aves)

• Characterized by feathers and toothless beaks.

• High metabolic rate.

• Lay hard-shelled eggs.

3- Reptiles (Class Reptilia)

• Include tetrapods such as snakes, crocodiles, and turtles.

• Characterized by being ectothermic.

• Snakes are still considered tetrapods though they have no visible limbs, as they evolved from ancestors that had limbs.

• Most reptiles today are cold-blooded

4- Amphibians (Class Amphibia)

• Characterized by breeding behavior.

• Most need a body of water to breed as their eggs are shell-less.

• They undergo metamorphosis where the young ones transform from fully aquatic larval form (with gills and fins) to terrestrial adult form.

5- Bony fishes (Class Osteichthyes)

• Characterized by their skeleton which is composed primarily of bone rather than cartilage

• Largest class of vertebrates today.

6- Cartilaginous fishes (Class Chondrichthyes)

• Characterized by the cartilaginous skeleton.

• Members include sharks, rays, skates, and sawfish. 

7-Jawless fishes (Class Agnatha)

• They have a jawless, circular mouth.

• Have rows of small sharp which aid in holding and feeding on other fishes.

• Most members of this class are parasites and scavengers.