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FLORIDA AMPHIBIANS Comprehensive Exam Study Guide

FORMAT KEY

  • → leads to

  • ↑↓ increase/decrease

  • ≡ defined as

  • ~ approximately

  • w/ with

  • b/w between

  • ♂♀ male/female

  • sp. species

  • spp. multiple species

  • FL = Florida

  • ★ = HIGH-PRIORITY EXAM TOPIC

EXAM STRUCTURE OVERVIEW

  • 20 Photo ID Questions:
      - Know diagnostic features for all 28+ species.
      - Features will be present even if photo differs from lecture.

  • 30 Multiple Choice:
      - Approximately 10 from guest lectures (e.g., Rio Caecilian invasion + others).
      - The rest from lecture content.

  • Priority Topics:
      - 4 diseases, Atrazine study, FL frog history, Gossner scale, sexual dimorphism, toxins, foot types, tadpoles, development types, endemic vs. invasive.
      - ★ High-priority exam topics.

WHAT CLASSIFIES SOMETHING AS AN AMPHIBIAN?

  • Class Amphibia
      - Ectothermic (cold-blooded) tetrapod vertebrates.
      - Name originates from Greek terms amphi (both) + bios (life), translating to a "life in two worlds" (aquatic + terrestrial).

Defining Characteristics

  • ★ Ectothermic:
      - Body temperature is controlled by the environment; amphibians cannot generate internal heat.
      - Thermoregulation is behavior-dependent.

  • Moist, glandular skin:
      - Amphibians do not have scales, feathers, or hair.
      - Their skin is permeable, enabling cutaneous respiration.
      - Glands present in the skin produce mucus (to maintain moisture) and toxins (for defense).
      - There is no waterproofing; amphibians are vulnerable to desiccation.

  • Double life:
      - Typically, amphibians undergo an aquatic larval stage (which is gill-breathing) that metamorphoses into a semi-terrestrial adult form (capable of both lung and cutaneous respiration).
      - There are exceptions, such as direct developers.

  • Gill-breathing larvae:
      - Larvae typically possess external or internal gills.
      - Adult amphibians generally have lungs plus the ability to perform cutaneous respiration.

  • Anamniotic eggs:
      - Eggs lack amnion, chorion, and allantois.
      - Must remain moist and cannot survive desiccation.
      - Typically, eggs are laid in water or moist sites; exceptions exist in some direct developers.

3 Living Orders of Amphibians

  1. Anura (frogs + toads)

  2. Urodela/Caudata (salamanders + newts)

  3. Gymnophiona (caecilians)

Tetrapod Characteristics

  • Tetrapod:
      - Amphibians typically have 4 limbs, though limbs may be reduced or absent in caecilians and some salamanders.
      - They are descended from lobe-finned fish approximately 360 million years ago (mya).

Cutaneous Respiration

  • Amphibians can absorb O2O_2 and lose CO2CO_2 through their moist skin.

  • Some lungless salamanders depend entirely on this form of respiration.

  • This characteristic makes amphibians sensitive to pollutants that come into contact with their skin.