3.10: Animalia- body plans, phyla and classes

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From Georges Cuvier times, highest animal groups (phyla) are understood as different body plans (Fig. 3.10.2).

There are some important animal phyla with notes about their body plans. Note that most of mentioned characters do not belong to the 100% of phylum species. As biology is a science of exceptions, this is normal. The following table lists many of animal phyla and also classes of chordates. Look also on “split pyramid” scheme (Fig. 3.10.1).

3.10.01.PNG — Figure 3.10.1 : “Pyramid of Life”, with more splits

Subregnum Spongia: no symmetry

Phylum 1. Porifera: sitting filtrators with skeletal spicules (H)

Subregnum Cnidaria: radial symmetry, stinging cells

Phylum 2. Anthozoa: sitting, colonial, with skeleton (I)

Phylum 3. Medusozoa: swimming, solitary, soft (A)

Subregnum Bilateria: bilateral symmetry, likely originated from crawling habit

Infraregnum Deuterostomia: with specific embryogenesis

Phylum 4. Echinodermata: small-plate exoskeleton, secondary radial, water-vascular appendages (E)

Phylum 5. Chordata: head and tail, gills in pharynx, axial skeleton (B)

Subphylum Vertebrata: vertebral column

Pisces: fish-like, gills

Classis 2. Chondrichtyes: cartilaginous, live in ocean

3. Actinopterygii: boned, rayed fins

4. Dipnoi: boned, thick fins, gills and lungs

Tetrapoda: four legs

Superclassis Anamnia: water eggs

Superclassis Amniota: terrestrial eggs

Classis 6. Reptilia: no feathers, four-pedal

7. Aves: feathers, bipedal

8. Mammalia: grinding jaws, fur, milk

Infraregnum Protostomia: specific embryogenesis

Superphylum Spiralia: worms, mollusks and alike

Phylum 6. Mollusca: shell, body straight (F)

Phylum 7. Lophophorata: shell and alike, body curved (J)

Phylum 8. Annelida: naked, segmented (G)

Superphylum Ecdysozoa: molting, with chitinous cuticle

Phylum 9. Nemathelminthes: worms with bending motion and primary cavity (C)

Phylum 10. Arthropoda: both body and appendages segmented (D)

Classis 1. Chelicerata: spiders, ticks, mites, scorpions

2. Malacostraca: crabs, lobsters, shrimp

3. Hexapoda: insects and alike

3.10.02.PNG — Figure 3.10.2 : Ten animal body plans, corresponding with phyla. See the text for explanation of letters.