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Bio 325 Lecture+26+Fall+2024

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Bio 325 Lecture+26+Fall+2024

Lecture 26: Origin and Diversification of the Diapsida, cont.


    • Date: Monday, Dec. 16, 8 – 10 am

    • Total Points: 150

    • Breakdown:

      • Lectures 19 – 26 (100 points)

      • “Big Picture” (50 points)


Phylogenetic Tree Construction

  • Draw a phylogenetic tree illustrating relationships among:

    • Testudines

    • Chondrichthyes

    • Lissamphibia

    • Lampreys

    • Cephalochordates

    • Mammalia

    • Hagfishes

    • Actinopterygii

    • Aves

    • Squamata

    • Sarcopterygii

    • Crocodylia

  • Key Steps:

    1. Construct tree based on widely accepted evolutionary relationships from BIOL 324.

    2. Map synapomorphies defining key branches:

      • Temporal fenestrae

      • Vertebrae

      • Endothermy

      • Notochord

      • Jaws

      • Amniotic egg

      • Paired fins/limbs

      • Pharyngeal slits


Archosauria

  • Clades Involved: Crocodylia + Dinosauria (includes modern birds)

Synapomorphies of Archosaurs:

  • Eggs with hard calcium carbonate shell

  • Nests built from vegetation

  • Some degree of parental care

  • Antorbital and mandibular fenestrae

    • Note: Secondary loss in crocodilians


Diversity of Extant Crocodylians

  • Alligatoridae:

    • Habitat: Freshwater to