W2 L3b - Amphibians Flashcards
What are the three orders in the class Amphibia?
- Gymnophiona (Caecilians)
- Caudata (Salamanders)
- Anura (Frogs & Toads)
What era did the amphibians evolve during?
Triassic Era
In what order did each of the Amphibia orders evolve in?
- Caecilians
- Salamanders
- Frogs
What biodiversity hotpots are amphibians found in usually?
Tropical Climates
What are the defining features of amphibians?
- Four well-developed limbs
- 3-chambered heart
- Carnivorous
- Ectothermic
- Improved kidney -> Dilute urea in adults
- Unique features for hearing
- Altered vision
- Moist, permeable skin -> Respiration, Habitat restrictions, Predator avoidance
- Respiration through -> Gills (larvae) and Lungs (adults)
- Metamorphosis
- Reproduction highly variable -> Largely dependent on water
What aided amphibians in breathing on land?
The Buccal Pump
How did the Buccal Pump work?
While breathing in:
1. Nostrils opened, Buccal cavity expands
2. Nostrils close, Glottis opens, Buccal cavity contracts, Lungs expand
While breathing out:
1. Buccal cavity expands, Lungs contracts
2. Nostrils open, Glottis closes, Buccal cavity contracts
Order Gymnophiona (Caecilians)
- 181 species
- Highly derived
- Limbless; short, pointed tails
- Burrowing movements using annuli (rings)
- Fused skull parts give strength
- Protrusible eyes and tentacles (under eyes)
- Internal fertilization
- Parental care -> from mother’s skin
- Tiny scales
Order Caudata (Salamanders and Newts)
- 619 species
- Ancestral tetrapod body
- Forelimb and hindlimb equal
- Lateral undulations, alternate limb movements
- Tail retained post-metamorphosis
- Limb regeneration (autotomy)
- Internal/external fertilization: aquatic larvae/direct development (incl. ovoviviparity)
- Paedomorphosis common (keeping juvenile features)
- Varied reliance on water as adults
- Varied Respiration: many lack lungs
- Adaptations for hunting: hyoid bone, sticky tongue, vision
- Toxins
- Lack external ear
Order Anura (Frogs)
- 5,400 species
- Present on all continents except Antarctica
- Only amphibians native to Australia
- Varied modes of living: Terrestrial, Arboreal, and Aquatic
Describe Frog Locomotion
- Larvae swim (ancestral mode)
- Adults have specialized skeletons for jumping: hind limbs, pelvic girdle, vertebrae
- Three categories of locomotion: jumping, swimming, walking/climbing
In frogs, how do longer forelimbs and longer hindlimbs aid in locomotion?
Walking-jumping and Jumping
In frogs, how do longer forelimbs and shorter hindlimbs aid in locomotion?
Walking-hopping and hopping-burrowing
In frogs, how do shorter forelimbs and longer hindlimbs aid in locomotion?
Hopping and swimming
In frogs, how do shorter forelimbs and shorter hindlimbs aid in locomotion?
Walking-hopping-burrowing
What are the different ways frogs procure and process food?
- Aquatic larvae -> filter feeding herbivores
- Aquatic adults -> suction feed
- Semi-aquatic/Terrestrial Adults -> project tongue to catch moving prey; head size determines prey size; large, bulging eyes aid in swallowing; sticky spit!
Describe Frog Reproduction
- Mating calls
- structural vibration and amplification - Mating Behavior
- semaphoring in males to compete with each other - Fertilization
- Amplexis: male holds female around waist in a “mating hug” - Lay eggs; highly variable
- larvae (and other strategies)
Do frogs have parental care, and if so, what are they?
Yes, body surface, skin pockets, vocal sacs, and stomach
What goes on during a Frogs Metamorphosis?
- Tadpole structures broken down; chemical constituents rebuilt into structures of adults
- Period of supreme vulnerability to predators & parasites
- Loss of gills -> Lungs developed
- Hormonally (thyroid) controlled
How do Frogs avoid predation?
- Camouflage/looking like other creatures
- Poison glands
- Bright/exotic colors
How do Frogs deal with extremes?
- Freezing Frogs
- Urea and glucose; reduce drying & stabilize cells - Rain Frogs
- Aestivation; prolonged torpor/dormancy during a hot or dry period
Which suborder of Frogs represent 96% of total frog diversity?
Neobatrachia
What are the 4 families of Neobatrachia Frogs we will study?
- Hylidae
- Bufonidae
- Dendrobatidae
- Ranidae
How many families and species are in Neobatrachia?
17 Families and 5,000 species
