Amphibians lecture

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Terms in this set (...)

Head start programs
removal of eggs from wild, rearing the eggs, larvae, and juveniles in captivity, then reintroducing them to supplement existing populations
Poison gland location
Posion glands in Bufonidae toads are located in the warts on the back and the paratoid glands behind the eyes while salamanders have poison concentrated in the tail.
Tarichatoxin
In newts, highly toxic, blocks signals from the brain to the heart, water-soluble alkaloid
Bufotoxin
in Bufonidae toads, releases a replusive taste and causes hallicinations
Poison dart frogs toxin
Poison originates from the diet of the frog
Difference between mudpuppies and hellbenders
Mudpuppies have a tapered snout where as hellbenders have a broadly rounded snout
unken reflex
Salamandridae arch their body to expose the brighter color of the ventor
cornification
dense accumulation of the protein keratin that facilitates the grip on the female during amplexus
Monophyletic features
Tooth structures, organization of middle ear, inner ear, retina of the eye, levator bulbi muscle, fat bodies, integument glandular
Pedicellate teeth
Crown and base of tooth separated by uncalcified dentine; may allow tooth to flex for prey handling
Oparcullum and columella complex
Two bones in middle ear that transmit sound to inner ear. High frequency air sounds cause columella to vibrate, low frequency ground sounds cause opacullum to vibrate
Amphibian papillae
mass of sensory cells sensitive to sounds less than 1,000 hertz coming from the ground
basilar papillae
allows them to hear air borne sounds
Green rods
specialized rods that detect shade differences
Paratoid gland
concentration of poison glands at base of the head
Breeding glands
glue males to females
Lipid glands
modified mucous glands that allows frogs to live in windy environments
Levator bulbi muscle
muscle that allows eye to elevate out of body
Fat bodies
form on gonads to store energy
Mucous glands
keeps skin moist
Dermal chromatophore unit
organized cells that are associated with color change
Melanophore
bear pigment Melanin (dark brown); pushing and pulling melanin through arms changes color
Aposomatism
warning colors
Xanthophores
associated with yellow coloration
Iridiphore
"iris- rainbow" multiple coloration; reflects light and comes back as blue
Erythrophore
bright red coloration
General life cycle
Aquatic eggs/larvae-metamorphosis-terrestrial juveniles/adults
Paedomorphosis
no metamorphosis; facultative and obligate; mature sexually while still in a larval form
Facultative
some individuals undergo metamorphosis but other do not- determined by environmental factors like temperature
Obligate
always remain in larvae stage
Partial metamorphosis
changes only some larvae characteristics
Direct development
embryo and larvae stage in the egg, hatches into mini adults: Plethodon
Metamorphosis process
blood travels from the hypothalmus to the pituitary gland which releases prolactin and thyroid stimulating hormone which signals the thyroid gland to release thyroxine, triiodothyronine, and tetraiodothyronine which signals metamorphosis to start
Amplexus
gripping of male and female
Biddler's organ
will develop ovaries if testes are damaged in Bufonid toads
Ultimate factors
daylength, ground saturation, and temperature
Proximate factors
cue when to breed on a certain day: rainfall
External fertilizers
Cryptobranchidae and Sirenidae
Spermathecae
chambers on cloaca walls that store sperm in female
Spermatophore
sperm bearing structures
eft stage
juvenile terrestrial wandering stage
Amphibians ecosystem importance
Take invertebrates energy and transfer to biomass and then energy for their predators
Amphibian decline factors
UVB radiation, pesticides, chytrid fungus, ranavirus, habitat destruction, climate change, invasive species
UVB radiation
developmental abnormalities and reduces larval stages
Overexploitation
pet trade, prized for frog legs, used as bait, research, and education
Habitat destruction
changes to ecosystem causes population isolation due to removal of linking habitat
Metamorphosis stages
premetamorphosis, prometamorphosis, and metamorphic climax
Premetamorphosis
tadpoles increase in size
Prometamorphosis
hind legs appear and growth of body continues
Metamorphic climax
fore legs emerge and tail regresses
Metamorphosis is stimulated by
thyroxine controlled by thyroid stimulating hormone
Cryptobranchus meaning
"hidden" "gill"- they do not retain external gills
Bolitoglossine meaning
"dart" "tongue"- able to project their tongue long distances
Nasolobial groove
salamander presses snout to the ground, fluid is drawn into the grooves and nasal chambers and over chemoreceptors in the vomeronasal cavity
urostyle
fused vertebrae in Anura
Internal fertilization of salamanders
transfer of a packet of sperm into the cloaca of the female
mental gland
pheromone secretions are applied to the nostrils of female with a slapping motion in Plethodontidae
Explosive breeding
very short season (only a few days); triggered by rainfall
Prolonged breeding
last for months; males compete for females
chytrid fungus
extends through the skin and interferes with respiration and control of water movement
Difference between Ambystoma texanum and Ambystoma barbouri
the lingual cusps in texanum are greatly elongated while barbouri have short lingual cusps
Tail loss in Plethodontid
defense mechanism; tails, toes, and limbs regrow rapidly
Frog vs Toads
Toads skin is thicker and secretes more mucus; frogs remain near water and have a urinary bladder