CHORDATE DIVERSITY PRACTICAL

  • General Instructions

    • The laboratory contains specimens representing different classes of the phylum Chordata.

    • Focus on the chordate features that demonstrate adaptive radiation, specifically:

    • Limbs

    • Skulls

    • Teeth

    • Participants are required to:

    • Carefully handle the specimens.

    • Answer accompanying questions on the answer sheet.

    • Draw and label the specimens accurately, utilizing sharp pencils and solid outlines without shading.

    • Observe and sketch the actual shapes and proportions from the specimens rather than copying diagrams.

CHORDATE SPECIMENS

  • Figures:

    • Fig 1. Frog Skeleton (Dorsal Surface)

      • Key components to label:

        • a: Astragalus

        • c: Calcaneus

        • d: Suprascapular

        • e: Exoccipital

        • f: Femur

        • fp: Frontoparietal

        • g: Metacarpals

        • h: Humerus

        • i: Ilium

        • h: Metatarsals

        • l: Carpus

        • m: Maxilla

        • n: Nasal

        • o: Prootic

        • p: Pterygoid

        • pm: Premaxilla

        • q: Quadratojugal

        • r: Radio-ulna

        • s: Squamosal

        • se: Sphenethmoid

        • s.v.: Sacral Vertebrae

        • t: Tibio-fibula

        • u: Urostyle

    • Fig 2. Skulls of Chordates

      • Types include: Anapsids, Diapsids, Euryapsids, and Synapsids.

      • Important to note: Number of temporal fenestrae in specimens.

FISH

  • Fig 3. Different Fin Types

    • Draw and label the pectoral fins of:

      1. Skate

      2. Lungfish (Neoceratodus)

      3. Teleost (e.g., perch or chub)

  • Draw bones in the operculum of a teleost fish, using perch or chub as examples.

    • Fig 4. Teleost Head Skeleton for reference in identifying the operculum in the specimens.

AMPHIBIANS AND REPTILES

  • Skeleton Comparisons

    • Provide brief descriptions to highlight differences between:

      1. Frog (Rana)

      2. Salamander (Salamandra)

      3. Lizard (Lacerta)

      4. Snake (Natrix)

TURTLES

  • Question:

    • Could a turtle crawl out of its shell?

    • Explanation required for why or why not.

SKULL AND DENTITION COMPARISON

  • Draw the skulls of:

    1. Crocodile

    2. Constrictor Snake

    3. Turtle

    • Label main differences including:

      • Jaws

      • Teeth

      • Temporal fenestrae

BIRDS AND MAMMALS

  • Draw:

    1. Pigeon Wing

    2. Bat Wing

    • Highlight how the basic pentadactyl limb is modified in both cases.

    • Discuss similarities and differences in how each limb design contributes to an increased surface area for flight.

ARCHEOPTERYX VS PIGEON

  • Compare the diagram of Archaeopteryx with the actual skeleton of a pigeon.

  • Note the major differences and relate them to flight capabilities, suggesting labels on diagrams to illustrate.

FORM AND FUNCTION OF LIMBS

  • Study the following limbs:

    1. Swimming Mammal

    2. Digitigrade Mammal

    3. Flying Mammal

    4. Burrowing Mammal

  • Focus on:

    • Form and function

    • Illustrate modulations of bones in the pentadactyl limb through diagrams, noting differences and adaptations for movement.

SKULL AND DENTITION ANALYSES

  • Compare and contrast skulls and dentition of:

    1. Dog

    2. Lion

    3. Baboon/Primates

    4. Kangaroo/Wallaby

    5. Dolphin

  • Pay particular attention to:

    • Structural characteristics of skulls

    • Variations in tooth structure and their functional adaptations in different species.