Lissamphibia Lecture Flashcards
What issue do terrestrial vertebrates face in terms of reproduction?
Desiccation of eggs. Terrestrial vertebrates have evolved methods of internal fertilization and gestation to overcome this.
If a frog is trying to hear a high frequency sound, what will happen in its ear?
The opercularis muscle will contract, causing low frequency vibrations to not be transmitted and only high frequency vibrations will be transmitted to the Papilla basilaris for detection.
If a frog is trying to hear a low frequency sound, what will happen in its ear?
The columellaris muscle will contract, causing high frequency vibrations to not be transmitted and only low frequency vibrations will be transmitted to the Papilla amphibiorum for detection.
What do the Hedonic glands in frogs secrete?
Pheromones
What benefits do mucous secretions in frogs have?
-Evaporative cooling
-Oxygen uptake and CO2 disposal
-Mating
-Prevents desiccation
-Antimicrobial
How can frogs breathe through their skin?
Mixed blood is pumped from the right side of the heart through the cutaneous artery, which takes it to the capillary beds in the dermis where the blood can then pick up oxygen and dispose of CO2. This mechanism is also seen in their buccal cavity.
How is oxygenated and deoxygenated blood kept separate in an Anuran heart?
The shape of the ventricle is able to be manipulated to segregate oxygenated and deoxygenated blood
When do Anurans utilize cutaneous respiration?
When they are underwater. Because of this, they can spend extended periods of time underwater without having to surface
Which hormone is responsible for inducing metamorphosis?
Thyroxine released by the thyroid
What is the hormone called that acts as a negative feedback to delay metamorphosis?
Prolactin released by the pituitary
How do salamanders reproduce?
A male deposits a spermatophore, then uses specific behaviours to rub pheromones secreted by hedonic glands onto the female, causing her to ovulate and pick up the spermatophore. Fertilization is internal.
What characteristics does the ancestral form of an Anuran have?
-More toes (5 instead of 4)
-Specialized and short pelvis
-No urostyle
-Trunk is longer
-Short hindlimbs and toes
What does a long forelimb length indicate?
That the frog is likely more of a walker
What does a long hindlimb length indicate?
That the frog is likely a long-distance jumper
Why do frogs crouch?
The reduce their surface area, thereby reducing water and heat loss
What are some parental care strategies used by frogs?
-Guarded by male
-Make a foam that defends and prevents the eggs from drying out
-Folded into a leaf
-Eggs carried on the frogs back
-Eggs carried in the vocal sacs
What are some reasons that frogs use calls?
-Mating
-Defending territory
-Warnings
What are some costs/risks associated with calling?
-Attracting predators
-Water loss
-Energetically costly
What types of mouths can tadpoles have?
-Superior (surface feeding)
-Terminal (filter)
-Subterminal (bottom feeder)
-Suction (scrapes algae)
-Siphon (passive filter feeding)
Why do Caecilians have skulls with very few holes?
Because of their digging lifestyle. More holes would lead to fractures in the skull
What threats do amphibians face?
-Habitat loss
-Climate change
-Pollution
-Disease (chytridiomycosis)
What body systems must be modified to sustain the transition to land?
Desiccation, musculature, waste excretion, sensory systems, reproduction, respiration, and thermal control
What are the skeletal modifications necessary for the transition to land?
Development of the neck and zygapophyses, development of sacral vertebrae, paired fins into paired limbs, development of an ankle joint, and fin elements into digital elements
What are zygapophyses?
Paired bony projections that extend from the vertebrae in the spine of vertebrates