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 the photo differs from lecture.
  • 30 Multiple Choice: Approximately 10 from guest lectures, including the Rio Caecilian invasion and others; the rest from lecture content.
  • Priority Topics:
      - 4 diseases
      - Atrazine study
      - Florida frog history
      - Gossner scale
      - Sexual dimorphism
      - Toxins
      - Foot types
      - Tadpoles
      - Development types
      - Endemic vs. invasive

WHAT CLASSIFIES SOMETHING AS AN AMPHIBIAN?

Class Amphibia
  • Definition: Amphibians are ectothermic (cold-blooded) tetrapod vertebrates. The name derives from Greek, with "amphi" meaning both and "bios" meaning life, indicating their existence in two worlds: aquatic and terrestrial.
Defining Characteristics

  1. Ectothermic
       - Body temperature is controlled by the environment, as amphibians cannot generate internal heat.
       - They exhibit behavior-dependent thermoregulation.

  2. Moist, Glandular Skin
       - Amphibian skin lacks scales, feathers, or hair and is permeable, allowing for cutaneous respiration.
       - Skin glands produce mucus to maintain moisture and toxins for defense.
       - There is no waterproofing, making them vulnerable to desiccation.

  3. Double Life
       - Amphibians typically undergo an aquatic larval stage (gill-breathing), followed by metamorphosis into a semi-terrestrial adult stage that utilizes both lung and cutaneous respiration.
       - Exceptions to this include direct developers that bypass the larval stage entirely.

  4. Gill-Breathing Larvae
       - Larval amphibians usually either possess external or internal gills.
       - In adults, lung and cutaneous respiration are the primary modes of breathing.

  5. Anamniotic Eggs
       - Amphibian eggs do not have an amnion, chorion, or allantois, necessitating a moist environment for survival, as they cannot withstand desiccation.
       - Eggs are typically laid in water or moist environments, although some direct developers exhibit different laying habits.

3 Living Orders of Amphibians
  1. Anura (frogs and toads)
  2. Urodela/Caudata (salamanders and newts)
  3. Gymnophiona (caecilians)
Tetrapod Characteristics
  • Amphibians possess four limbs (or have reduced/absent limbs in caecilians and some salamanders), descending from lobe-finned fish approximately 360 million years ago.
Cutaneous Respiration
  • Amphibians can absorb oxygen and lose carbon dioxide through their moist skin.
  • Some lungless salamanders rely entirely on this form of respiration, rendering them sensitive to skin contact pollutants.