Bio 325 Lecture+26+Fall+2024

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

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  • 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