Anatomical Terminology & General Stuff

Symmetry in Animals

• Spherical symmetry: Bisection through any plane passing through center (e.g., Volvox).
• Radial symmetry: Bisection into equal halves via central line (e.g., anemones, jellyfish).
• Bilateral symmetry: Bisection by one plane into relatively equal halves (e.g., planarians, vertebrates).

Circulatory Systems

• Closed circulatory system: Blood contained within vessels.
• Open circulatory system: Blood pools within the body.

Kingdom Animalia

• Multicellular eukaryotic heterotrophs.
• Excludes prokaryotes, protists, fungi, or plants.
• Main groups: Invertebrates (no backbone) & Vertebrates (backbone).

Essential Life Functions

• Feeding: Gathering food.
• Respiration: Obtaining oxygen.
• Internal transport: Moving nutrients.
• Excretion: Removing nitrogenous waste.
• Sensitivity: Sensing environment.
• Reproduction: Generating offspring.
• Movement: Self-explanatory.

Coelom

• Acoelomates: No coelom (e.g., flatworms).
• Pseudocoelomates: "False" coelom (e.g., roundworms).
• Coelomates: True coelom (e.g., annelids, vertebrates).

Phylum Porifera

• Sponges: Invertebrates, often radially symmetrical.
• Habitat: Aquatic, mostly marine.
• Feeding: Filter feeders.
• Anatomy: Central cavity, osculum, porocytes, spicules, amebocytes, choanocytes.
• Reproduction: Sexual (hermaphroditic) & asexual (budding).

Phylum Cnidaria

• Examples: Jellyfish, hydra, anemones, coral.
• Symmetry: Radial symmetry.
• Body shapes: Polyp (sessile), Medusa (mobile).
• Anatomy: Tentacles, gastrovascular cavity, nematocysts.
• Reproduction: Sexual & asexual (budding).

Phylum Platyhelminthes

• Flatworms: Tapeworms, planaria.
• Symmetry: Bilateral.
• Complexity: Simplest organisms with cephalization.
• Reproduction: Sexual (hermaphroditic) & asexual (fission).

Phylum Annelida

• Segmented worms: Earthworms, leeches.
• System: Closed circulatory system.
• Reproduction: Hermaphroditic, not self-fertilizing.

Phylum Nematoda

• Roundworms: Ascaris, hookworms.
• Symmetry: Bilateral, pseudocoelomates.
• Reproduction: Sexual, distinct sexes.

Phylum Echinodermata

• Examples: Sea stars, sea urchins.
• Symmetry: Pentaradial symmetry.
• System: Water vascular system.
• Reproduction: Sexual & asexual (fission).

Phylum Mollusca

• Examples: Snails, clams, octopus.
• System: Open (gastropods/bivalves) & closed (cephalopods) circulatory systems.
• Classes: Gastropoda, Bivalvia, Cephalopoda.

Phylum Arthropoda

• Examples: Insects, spiders, crabs.
• System: Open circulatory system.
• Reproduction: Complete/incomplete metamorphosis.
• Classes: Insecta, Arachnida, Crustacea.

Phylum Chordata

• Characteristics: Dorsal nerve cord, notochord, gill slits, post-anal tail.
• Subphyla: Urochordata, Cephalochordata, Vertebrata.
• Vertebrates: Fish, birds, reptiles, mammals.

Classifications & Key Features

• Fish: Agnatha, Chondrichthyes, Osteichthyes.
• Birds (Aves): Endothermic, feathered.
• Reptiles: Ectothermic, keratin scales.
• Mammals: Endothermic, fur/hair, live birth (except Monotremes).