Animal Identification and Phylogenetic Revision Guide

Objective: This revision exercise is designed to facilitate the retention of different animal groups and their respective key characteristics discussed throughout the course.
Structural Approach: The exercise utilizes a branching tree structure representing phylogenetic decision points.
Navigational Logic: - Learners should start at the far left of the tree diagrams. - At every branching point (a 'decision point'), the learner must identify the specific traits or characteristics that determine whether an animal belongs to one lineage or the other.
Example Case: When faced with the decision point between Bilateria or Non-bilaterian, a learner should ask a diagnostic question such as, "Is this animal bilaterally symmetrical?"
Suggested Study Techniques: - Quizzing peers using new or unfamiliar animal species to see where they land on the tree. - Filling in the empty spaces or decision points with the specific biological traits associated with each clade.

Animalia: The root kingdom for all organisms in this exercise.
Primary Symmetries and Organization: - Non-Bilaterian: Organisms that typically lack bilateral symmetry. - Bilaterian: Organisms characterized by bilateral symmetry at some stage of their life cycle.
Bilaterian Lineages (Protostomes vs. Deuterostomes): - Protostome: A major lineage of bilateral animals where the mouth typically develops from the primary embryonic opening (blastopore). - Lophotrochozoa: A subgroup of protostomes. - Ecdysozoa: A subgroup of protostomes characterized by ecdysis (molting). - Deuterostome: A primary lineage of bilateral animals where the anus typically develops first from the blastopore. - Echinodermata: A subgroup of deuterostomes. - Chordate: A subgroup of deuterostomes characterized by specific anatomical landmarks.

Specific Examples: - Clavelina dellavallei: A representative organism within the chordate lineage. In visual representations, its scale is approximately $1\,\text{cm}$ . - Ciona sp.: Another representative used to illustrate chordate anatomy.
Key Diagnostic Traits of Chordates (Anatomical Landmarks): - Based on Figure 32.7 and 32.8 from Life: The Science of Biology 11e (Sinauer Associates, Inc. / Stan Elems/Visuals Unlimited, Inc. / Marevision/AGE Fotostock): - Notochord: A flexible, rod-like structure providing skeletal support. - Dorsal Hollow Nerve Cord: Part of the central nervous system located dorsal to the notochord. - Pharyngeal Slits: Openings or grooves in the pharynx. - Tail: A post-anal structure. - Gut: The digestive tract extending through the body.

Vertebrates: The root group for the following decision tree.
Initial Branching Points: - Jawless Fish: Basal vertebrates lacking a hinged jaw. - Gnathostome: Vertebrates possessing hinged jaws.
Gnathostome Sub-divisions: - Chondrichthyan: Cartilaginous fishes (e.g., sharks and rays). - Osteichthyan: The 'bony' vertebrates, characterized by a calcified skeleton.
Osteichthyan Lineages: - Actinopterygian: Ray-finned fishes. - Sarcopterygian: Lobe-finned vertebrates.
Sarcopterygian Branches: - Lungfish/coelocanth: Living lineages of lobe-finned fish. - Tetrapod: Four-limbed vertebrates.

Tetrapod: The root group for the final classification tree.
Primary Diversification: - Amphibian: A lineage of tetrapods that typically requires water for reproduction. - Amniote: Vertebrates that produce an amniotic egg, allowing for reproduction away from water.
Amniote Branches: - Synapsid: The lineage that includes mammals and their ancestors, characterized by a single temporal opening in the skull. - Testudes: Turtles and tortoises. - Diapsid: The lineage characterized by two temporal openings in the skull.
Diapsid Lineages: - Lepidosaur: Lizards, snakes, and tuataras. - Archosaur: A group of diapsids including crocodilians, birds, and extinct dinosaurs.
Archosaur Sub-divisions: - Crocodilia: Crocodiles, alligators, and caimans. - Aves: Birds.