Lesson 12 Flashcards
major synapomorphies
substantial gas exchange – skin has to be moist in order to exchange gas
- skin glands – keep skin moist – poision glands
– carnivery –> all exant adult amphibians are carniverous
salamanders
10 families of about 750 species
- almost entirely in NC
- gait of salamanders are very similar to that of the early tetrapod
- lot of axial bending, limbs not used for propelling
pedomorphoisism (salamanders)
- widespread
- absence of eyelids – not usually present in early embryos
- functional lateral line system
- external gills
all salamanders lack ribs
- no intercostal ventilation
- instead they use a buccal pump
—- presents a conflict because it is not compativle with tongue protrousion
plethodontidae (salamanders) (lungless)
- famous for ability for projecting tonguse rapidley to catch prey
- the distance a muscle can extend is proportional to the length of that muscle
- no lungs
- do all of the respiration across moist skin
- loss of lungs led to specific hypbranchial specialization
- requires some tradeoffs to being this specialized
- comes down to a conflict to feeding as an adult and feeding as a larvae
comes down to a conflict to feeding as an adult and feeding as a larvae
- aquatic larvae (generally) use suction feeding to bring up detritus that is sitting along the bottom of the ponds
- that sucction capability requires a large ceratobranchial to engage that succion like force
- having a big ceretobranchial conflicts with having the protrouding tongue mechanisms
- this kind og highly specialized form of plethodontiade salamander lack aquatic larvae thus no large ceratobranchial
nasolabial groove
functions in chemoreception
- taking things up like pheremones left by neighbors
- if you put one salamandeer in a neighboors habitat - the homeowner expressed a lot of hostility
- they are extremely terrirorial
- if done a second time – not as aggressive
- use the nasolabial gooves and chemoreception to detect whwther or not they know the salamander
- attack is much less intense if the paper used in the experiment had the same scent again
DEER - enemy - pheeremone – neighboors treated less aggressively
autotomy
- salamanders can loose a part of their tail or body and have to grow it back
- animals with messed up nasolabial grooves don’t pick up on the communication signals –> end up becoming loners
anurans
- almost everywhere
- true toads – phylogenetically distinct group
- poison dart frogs –> synthesize poision from ants
extant anurans
- forward directed eyes
- fused sacrum
- urostyle
- fused tibia and fibula
- loss of vertebrae, stiffening of vertebrae that remain
- flexible shock absorber
jumpers
- long hindlimbs
- medium length forelimbs
hoppers v. jumpers
- hoppers tend to have poison glands and jumpers do not
- jumpers tend to get away from their predators by jumping
tree frogs
- very good at clinging to very straight substrates
- modifications to toes called toe disks
caecilian
- some species don’t even have eyes
- burrow exclusively
- protrusible tentacles between eyes and snout – maybe detection of prey or pheremones
amphibians
- most lay eggs but some do not
- in some species – eggs are brooded in the mouth or stomach
^^^^^ adults undergo specific changres in their digestive system to make sure that the offspring are not digested - some have a form of parental care
—– poison frog
—— paternal care as well (really rare)
——- lay egges in these plants that grow on the side of trees that form basins of water –> they lay eggs in those plants (bromiliad) – the father will transport the eggs if the water dies up to a differnt place
caecilians again
- have internal fetalization
- about 75% give live birth as opposed to laying eggs
salamanders internal fertilization
- accomplish internal fertilization WITHOUT a penis
HOW - males deposit these “packets” of material that contain their sperm and will drop them on the floor during the mating ritual – if the female wants to, she will pick up the spermatophore and place it in her cloaca ergo internal fertilization
clepogenesis
- no males, only females
- produce eggs that get actvivated by the sperm of another species —> the sperm does not get into the egg
– can be triploid or even pentaploid
courtship of salamanders
pheremones
- wafting his odor near the female to get her to accept
- most of these behaviors involve communication of information via courtship
sexual dimporhism
physical differences between males and females ( can also have behavioral traits)
why do frogs vocalize
- to attract mates
- to advertise themselves
- mostly exclusively male
the more a male calls – the greater the volume of oxygen per gram per hour (VO2) –» tells us that calling is metabolically exertive
- a lot of their energy is spent on this behavior
frog sitting in chanber
- chamber is sealed except for a tube with a measured quantity of oxygen
- other end is another tube to measure the output of oxygen
^^^ this apparatus allows the scientists to quantify the oxygen consumption
what do female frogs prefer
mates who call the most
– exhibits their ability/stamina – physical prowness
- to pass the gene to their ofspring
good gene hypothesis
females show preferences for these traits becasue the continuous calling mean good genes and she wants them to be passed onto her offspring
direct advance hypothesis
- by preferring these genes
- these males grew stronger because they might have had better access to resources
- could be the case that the male has better resources and better habitat – thus by mating with um – the offspring wil lbave a better advantage
experiment for frog mating
- took males that were already calling and allowed the high calling males to sire half of the femal clutch of eggs and used the other half to be sired by low calling males –> genetic contribution of female is the same –> but they are not allowing the female to choose the mate
– when they grew up — the offspring of the higher calling males lived longer and grew up faster than the low calling males
tungara frog
- get the name from the call they make
- chuck and wine
- females overwhelmingly perfer the complex call (combo of chucks and wines) as opposed to a single
- frog eating bats also perfer the complex call
- complex call also attracts parasitic flies
everyone of these species has a simple call
- not all have this complex call
- the females have a preferance for the complex call even if the males of their own species never make that call
- ^^^ its argued that males evolved complex call to explot the already preexisting trait in the female nervous system
—— could be normal for the NS of the female to be more stimulated by the complex sound
——- males might have exploited this to get the ability of mating – increase mating preference
AVOID PREDATORS
- frogs will lay eggs on the underside of leaves that are above the water
- when jiggling occurs – the eggs will prematurely hatch and fall into water to avoid predators
- poision dart frog carries tadpoles on back
in order to accomplish metamorphosis, a huge number of changes need to occur
- reorganization of the body
- nervous system, blood flow, mouth parts
- gill structure
- change in feeding apparatus
- vegetative manner like detritus (what tadpoles eat) is much more difficult to digest
- tadploles have an extensively coiled small intestint to increase surface area to digest the plant matter
- that twisting will be changed into a much more simpler stomach to digest the bugs
- change – from using gills to using lungs for respiration
susceptibility – in the intermediate metamorphic state -
- 67% of prey captured was in water and 90% was on land –> very very susceptibe to predation – the ability to metamorphozize comes at a great cost
- in larvae – no really strong separation of blood
- in matured frogs - gill arches 3/4/5 change
- 5 is totally lost in the adult
- 3 becomes the arteries that form the head
- 4 goes to the rest of the body, arch6 in larvae goes to the dorsal aorta, but in adults it becomes the pumocutaneous artery
can shift from a lung usage to a gill usage
- depicted in the heart
- when flow is coming from the lungs, deoxygenated blood is arriving in systemic veins - right atrium - right pulmocurtanosy
- when flow is only used by the skin – no flow to pulmonary vein, oxygenated blood comes in by way of systemic veins (which was for deoxygenated blood in the lung breathing)
- don’t have waterproof skin like amniotes –> the frogs are very susceptible to waterloss
puerto rican frog
- during vocalization this one puerto rican frog – almost all of its body surface is exposed to evaporation
- they call all the time but call more during the rain
- when it is not raining they can assume a water-conserving posture where half of the body surface is protected from exposure
many frogs have posion glands
batrachotoxin
- their poison makes it so their prey cannot close their sodium channels ad they basically induce tetanus
mimicry
can scare predators with the brightly colored belly (for salamanders that are not poisonous)
- this one salamander species – red efft species and the red salamander– both of these have skin toxins that will deter predators
- the red back salamander is not protected with toxins but predators confuse the brigth orange color of the red back with the 2 above that are poisonous
- ^^^^^^ evolved mimicry
— the red efft poison blocks action potentials and leads to paralyzation `
rapid extinction of amphibians
- 40% of frog and salamander species are on the decline
- chytrid fungus is the culprit for much of this decline
- one of the proximate productions that leads to egg development – when conditions are right there will be rise in FSH and LH- (gonadal tropins) -
- HCGH (human hormone) can be injected into the frog and frog will produce eggs
– large number of african clog frogs were brought over to the US once this gene stuff was discovered
— WHY — HCGH causes frogs to lay eggs – people would inject a blood serum froma. woman who was maybe pregmant into the frogs and see if the frog lays eggs – PREGNANCY
^^^^ these chytrid frogs brought the chytrid fugus
