Animal Kingdom and Its Phyla

Ecosystem Overview

  • Definition: An ecosystem is an area where interactions occur between living (biotic) and nonliving (abiotic) things.

Animal Kingdom Overview

  • In-depth focus on the animal kingdom, which can be subdivided into nine smaller groups known as phyla.

  • Major phyla of the animal kingdom:

    1. Phylum Porifera

    2. Phylum Cnidaria

    3. Phylum Platyhelminthes

    4. Phylum Nematoda

    5. Phylum Annelida

    6. Phylum Mollusca

    7. Phylum Arthropoda

    8. Phylum Echinodermata

    9. Phylum Chordata

Phylum Porifera

  • Examples: Sponges

  • Characteristics:

    • Plant-like appearance but are animals; non-locomotor (sessile) and attach to underwater rocks.

    • Simplest body structure with bodies full of holes allowing water flow for feeding on suspended particles.

Phylum Cnidaria

  • Examples: Jellyfish, sea anemones, corals

  • Characteristics:

    • Have tentacles with stinging cells (nematocysts) for defense.

    • Exist in two body forms: medusa (umbrella-shaped) and polyp (vase-shaped).

Phylum Platyhelminthes

  • Examples: Flatworms (e.g., planarians, liver flukes, tapeworms)

  • Characteristics:

    • Flat-bodied, bilateral symmetry.

    • Some are parasitic and can have hooks and suckers for attachment to hosts.

Phylum Nematoda

  • Examples: Roundworms (e.g., Ascaris, Trichinella)

  • Characteristics:

    • Not segmented with smooth body surfaces.

    • Many are endoparasitic and have a complete digestive tract (mouth and anus).

Phylum Annelida

  • Examples: Earthworms, sandworms, leeches

  • Characteristics:

    • Body is segmented, enhancing locomotion and organ development.

    • Complete circulatory system for effective blood circulation.

Phylum Mollusca

  • Examples: Clams, snails, squids, octopuses

  • Characteristics:

    • Soft-bodied animals often with an exoskeleton (shell) for protection.

    • Muscular foot for locomotion and breathing structures (gills) for aquatic species.

Phylum Arthropoda

  • Examples: Crayfish, lobsters, crabs, insects, spiders

  • Characteristics:

    • Jointed legs, segmented bodies divided into sections, and an exoskeleton made of chitin.

    • Well-developed sense organs for interaction with their environment.

Phylum Echinodermata

  • Examples: Starfish, sand dollars, sea urchins

  • Characteristics:

    • Spiny skin for protection; body exhibits radial symmetry typically seen in adult forms.

    • Mobility facilitated by a water vascular system for locomotion.

Phylum Chordata

  • Examples: Humans, fish, amphibians, reptiles, birds, mammals

  • Characteristics:

    • All members possess a spinal cord (notochord) at some stage, classifying them as vertebrates.

    • Divided into seven classes:

    1. Agnatha: Jawless fish (e.g., lamprey)

    2. Chondrichthyes: Cartilaginous fish (e.g., sharks, rays)

    3. Osteichthyes: Bony fish (e.g., goldfish)

    4. Amphibia: Semi-aquatic animals with moist skin (e.g., frogs)

    5. Reptilia: Dry and scaly skin (e.g., snakes, lizards)

    6. Aves: Birds with wings and feathers for flight.

    7. Mammalia: Mammals that nurse their young and possess hair or fur (e.g., humans, apes).