PHYLUM BRACHIOPODA (Lamp Shells)
Characteristics:
- Commonly known as lamp shells.
- One of the lophophorate phyla.
- Possess a "U" shaped lophophore with beating tentacles surrounding the mouth.
- Most common animals of the Paleozoic sea.
- Bilateral symmetry.
- Triploblastic (three germ layers).
- Organs present.
- Tube-in-tube body structure.
- Classified under deuterostomes based on embryological patterns.
PHYLUM ECHINODERMATA
Characteristics:
- Larvae have bilateral symmetry; adults exhibit radial symmetry, with madrepore skewed to one side.
- Possess a water vascular system for feeding, locomotion, gas exchange, and sensory perception.
- Tube feet are present.
- Nerve ring made of nervous cells.
- Ossicles form a calcareous endoskeleton (spines/bumps).
- Separate sexes; all marine.
- Triploblastic (three germ layers) with organ systems present.
- Capable of regeneration (e.g., sea stars and sea cucumbers).
Class Asteroidea
- Includes sea stars (starfish) and sea daisies.
- Star-shaped body with mouth directed toward the substrate.
- Tube feet located on suckers, capable of arm regeneration.
Class Ophiuroidea
- Includes brittle stars.
- Slender body resembling a starved sea star; long, flexible arms.
- No tube feet on suckers.
Class Echinoidea
- Includes regular (sea urchins) and irregular (sand dollars) echinoids.
- Body (test) is made of fused plates; no arms.
Class Holothuroidea
- Commonly known as sea cucumbers.
- Soft-bodied with reduced spines and no arms.
- Capable of regeneration; defense mechanism is evisceration.
- Five rows of tube feet, with modified tube feet near the mouth for feeding.
Class Crinoidea
- Includes feather stars, basket stars, and sea lilies.
- Oldest and most primitive of echinoderms.
- Mouth points upward; fossilizes well in chert rock.
PHYLUM HEMICHORDATA (Acorn Worms)
Characteristics:
- Commonly known as acorn worms.
- Head region shaped like an acorn.
- Possess a dorsal nerve cord and pharyngeal gill slits.
- Gill slits and nerve cord indicate a relationship to chordates.
PHYLUM CHORDATA
Key Characteristics:
- Presence of pharyngeal gill slits.
- Presence of a notochord.
- Presence of a dorsal hollow nerve cord.
- Presence of a muscular post-anal tail and blocks of muscle.
PHYLUM CHORDATA
General Characteristics:
- Coelomate with bilateral symmetry.
- Tube-in-tube body plan.
- Triploblastic (three germ layers).
- Segmented body with present organ systems.
Subphylum Urochordata
- Includes tunicates and sea squirts.
- Adults are sessile and filter feeders, resembling a bag.
- Possess gill slits but lose other chordate characteristics in adult form; larval forms retain bilateral symmetry and all four chordate characteristics.
Subphylum Cephalochordata
- Commonly known as lancelets (e.g., Amphioxus/Brachiostoma).
- Filter feeders; adults retain all four chordate characteristics.
Subphylum Craniata
- Includes vertebrates (backboned animals).
- Backbone replaces the notochord, can be cartilaginous (e.g., hagfish and chondrichthyes) or calcified (all other vertebrates).
- Segmentation evident in muscles and vertebrae.
- Gill slits may be retained or modified in adult forms; tails may be present or only during embryonic stages.
GROUPING:PISCES (The Fishes)
CLASS MYXINI (Hagfish)
CLASS PETROMYZONTIDA (Lamprey)
GNATHOSTOMES
CLASS PLACODERMI
CLASS CHONDRICHTHYES
CLASS OSTEICHTHYES
Devonian was the
"Age of Fishes."
CLASS MYXINI (Hagfish)
- Characteristics:
- Jawless fish, grouped with lampreys as "cyclostomes."
- Highly reduced vertebrae; cartilage body support.
- Mouth has keratinized tooth-like structures.
- 2-chambered heart (1 atrium, 1 ventricle).
- Marine detritus feeders, secreting slime for defense.
CLASS PETROMYZONTIDA (Lamprey)
- Characteristics:
- Jawless, parasitic; penetrates host skin with teeth and tongue.
- Cartilaginous skeleton without collagen.
- Flexible sheath around notochord, with stiff projections.
- 2-chambered heart (1 atrium, 1 ventricle).
GNATHOSTOMES (Jawed Fishes)
- Characteristics:
- Developed hinged jaws; lateral line system for detecting vibrations.
CLASS PLACODERMI (Armored Fish)
- Characteristics:
- Extinct group known for plated skin.
CLASS CHONDRICHTHYES (Cartilaginous Fishes)
- Characteristics:
- Includes sharks, skates, rays, and ratfish.
- No swim bladder or lungs; retains urea for osmoregulation.
- Modified scales for teeth; 2-chambered heart; internal fertilization.
CLASS OSTEICHTHYES (Bony Fish)
- Characteristics:
- Bone replaces cartilage during development.
- Possesses operculum and may have a swim bladder.
- 2-chambered heart; most exhibit external fertilization.
subclass Sarcopterygii
Includes fleshy-finned fish (e.g., coelacanths).
subclass Actinopterygii
Includes ray-finned fish (e.g., goldfish, catfish).
grouping: tetrapoda
Class Amphibia
Class Reptilia
Class Aves (Birds)
Class Mammalia
Class Amphibia
- Characteristics:
- Evolved from lobe-finned fish; lungs and moist skin for gas exchange.
- 3-chambered heart; primarily external fertilization.
- Undergo metamorphosis; some show neoteny.
orders Class Amphibia
- Anura
- Urodela
- Apoda
Anura
Frogs and toads; observe preserved specimens.
Urodela
Salamanders and newts; observe preserved specimens.
Apoda
Legless, segmented worm-like forms.
Class Reptilia
- Characteristics:
- Ectothermic; 3-chambered heart (except crocodiles).
- Amniotic egg; keratinized, dry skin.
orders of Class Reptilia
- Chelonia
- Rhynchocephalia
- Squamata
- Crocodilia
Chelonia
Turtles and tortoises; observe specimens.
Rhynchocephalia
Tuatara; unique with a 3rd eye.
Squamata
Lizards and snakes; observe specimens.
Crocodilia
Alligators and crocodiles; only crocodiles have a 4-chambered heart.
Class Aves (Birds)
- Characteristics:
- Evolved from thecodonts; 4-chambered heart.
- Air sacs for gas exchange; hollow bones for lighter body.
- Endothermic; care for young; amniotic egg.
Class Mammalia
- Characteristics:
- Evolved from theapsids; hair made of keratin; mammary glands.
- 4-chambered heart; endothermic.
Groups of class mammalia
- Monotremes
- Marsupials
- Placentals
Monotremes
Egg-laying (e.g., platypus).
Marsupials
Immature young develop in pouch.
Placentals
Young nourished via placenta.