Biological Kingdoms and Animal Phyla: A Comprehensive Classification
Kingdoms of Life
Monera (Bacteria and Archaea)
- Characteristics: Unicellular, prokaryotic.
- Nutrition: Autotrophic or heterotrophic.
- Reproduction: Asexual.
- Locomotion: Possess flagella, capable of movement.
- Survival: Can produce resting spores.
- Subgroups: Eubacteria and Archaea.
Protoctists (Protists)
- Characteristics: Eukaryotic, unicellular or multicellular.
- Nutrition: Autotrophic or heterotrophic.
- Reproduction: Sexual or asexual.
- Locomotion: Mobile, move by cilia, flagella, or pseudopods.
- Subgroups: Protozoa and Algae.
Fungi
- Characteristics: Eukaryotic, unicellular or multicellular.
- Nutrition: Heterotrophic.
- Reproduction: Both sexual and asexual.
- Appearance: Varies according to humidity.
- Examples: Molds, yeasts, and mushrooms.
Plantae (Plants)
- Characteristics: Eukaryotic, multicellular.
- Nutrition: Autotrophic.
- Reproduction: Asexual (e.g., cuttings) and sexual (e.g., pollen).
- Responses: Exhibit phototropism and geotropism.
- Subgroups: Gymnosperms and Angiosperms.
Animalia (Animals)
General Characteristics:
- Eukaryotic, multicellular.
- Similarities in ribosomal RNA.
- Special intercellular junctions: tight junctions, desmosomes, and gap junctions.
- Synthesize collagen.
- Possess Hox genes, responsible for body organization.
Key Animal Phyla Include:
Choanoflagellates
- Description: Flagellate organisms, solitary or colonial.
- Significance: This cell type appears in Porifera and is considered ancestral to other animals.
Porifera (Sponges)
- Organization: Organized as more or less complex sacs, with body walls traversed by countless pores.
- Skeleton: Internal skeleton composed of spicules hardened with collagen.
- Evolutionary Novelty: Skeleton of spicules and an intermediate layer (mesoglea).
Cnidaria (Jellyfish, Corals, Anemones)
- Body Structure: Radial symmetry, with tentacles containing cnidocytes (stinging cells).
- Novelty: Exhibit two main body forms: polyp (sessile) and medusa (free-living adult).
Nematodes (Roundworms)
- Classification: Eukaryotic, multicellular, triploblastic (three embryonic layers: ectoderm, endoderm, mesoderm).
- Structure: Soft body and cuticle.
- Nutrition:
- Digestive System: Mouth, pharynx, stomach, intestine, anus.
- Excretory System: Protonephridia.
- Nervous System: Ganglia forming a ring around the esophagus.
- Reproduction: Sexual, dioecious (separate sexes), internal fertilization.
Arthropods
- Classification: Eukaryotic, multicellular, triploblastic, reduced coelom (body cavity containing organs), bilateral symmetry.
- Structure: Protected by a chitinous exoskeleton, body segmented into metameres.
- Nutrition:
- Digestive System: Mouth, esophagus, intestine, and anus.
- Circulatory System: Open, pumped by the heart.
- Respiratory System: Aquatic (gills), terrestrial (lungs or tracheae).
- Nervous System: Consists of a ring around the esophagus that captures light; compound eyes allow them to perceive movement.
- Reproduction: Sexual, internal fertilization.
Platyhelminthes (Flatworms)
- Classification: Eukaryotic, multicellular, triploblastic, acoelomate (lacking a body cavity), bilateral symmetry.
- Structure: Flattened body, initial cephalization (development of a head).
- Nutrition:
- Digestive System: Incomplete (mouth and anus are the same opening).
- Excretory System: Protonephridia.
- Nervous System: Ganglionic brain.
- Reproduction: Sexual (hermaphroditic) and asexual.
Molluscs
- Classification: Triploblastic, coelomates, bilateral symmetry.
- Structure: Soft, non-segmented body.
- Nutrition:
- Digestive System: Mouth (radula), stomach, intestine, and anus.
- Circulatory System: Consists of a heart and blood vessels (open or closed).
- Excretory System: Consists of metanephridia or kidneys.
- Respiratory System: By gills or lungs.
- Reproduction: Sexually, some are hermaphroditic (e.g., snails).
- Novelty: After hatching, the egg often produces a trochophore larva.
Annelids (Segmented Worms)
- Classification: Triploblastic, coelomates, bilateral symmetry.
- Structure: Body formed by metamerism (segmentation).
- Nutrition:
- Digestive System: Mouth, pharynx, esophagus, intestine, anus.
- Circulatory System: Closed circulatory system.
- Nervous System: Cephalization (head development) with two ganglia.