|Herp Diversity and Biogeography||Herp Morphology and Physiology||Herp Ecology and Behavior||Herp Life History and Reproduction||Herp Conservation etc.|
The ectothermic, terrestrial vertebrates
Reptiles and amphibians
What is a herp anyway?
1) Paedophryne amauensis is a species of microhylid frog endemic to eastern Papua New Guinea. At 7.7 mm (0.30 in) in snout-to-vent length, it is considered the world's smallest known vertebrate.
2) Chinese giant salamander
1) This is the world's smallest vertebrate, clocking in at 0.30 inches.
2) This is the world's largest amphibian, clocking in at 6 ft long and >80 lbs.
1) attract mates
2) deter competitors
What are the two primary functions of vocalizations in frogs?
Testudines and Crocodilia
Extra: Komodo dragon, reticulated python (anaconda is the heaviest)
All of the top 15 heaviest herps are in these two reptile orders.
Extra 100 points if you can name the largest lizard and longest snake in the world!
Brown treesnake in Guam
Cane toad in Australia
Puerto Rican treefrog
Pythons in Florida
Give one example of an invasive herp species that has negatively impacted a native ecosystem, and explain how.
Amphibs: Soft, permeable skin adapted for cutaneous gas exchange
Granular glands (secrete distasteful/poisonous substances)
Reps: Possess scales/scutes
Terrestrial ectothermic amniotes
Name two synapomorphies each of amphibians and reptiles.
Tetrodotoxin is an extremely potent poison (toxin) found mainly in the liver and sex organs (gonads) of some fish, such as puffer fish, Tetrodotoxin interferes with the transmission of signals from nerves to muscles and causes an increasing paralysis of the muscles of the body.
What do pufferfish and rough-skinned newts have in common, and what type of evolution is this an example of?
First documented in 2014!
Bearded dragon (Pogona vitticeps)
Used a simple experiment with a wooden board and a door
Food reward on the other side
Showed the test subjects a video of another dragon opening the door to either left or right
Control was a door that opened by itself
The subjects exposed to the video opened the door always in the same direction as the video they watched!!!!!
Do herps have complex social behavior? Why or why not? What was the first example of herp learning ever recorded?
Dwarfism: Madagascar dwarf chameleon; Paedophryne, PNG
Gigantism: Komodo dragon, Galapagos tortoise
Compare and contrast insular dwarfism and gigantism, and give examples of each
Important as predators and prey
Important for biomedical research
Critical bioindicators of ecosystem health
Food source for humans
Iconic examples used for ecotourism and popular culture
Give two examples of ecosystem services that herps provide.
blind snakes, amphisbaenians (lizards), caecilians (amphibians)
adapted to digging, subterranean lifestlye
loss of legs, vestigial eyes, elongate, cylindrical body plan
Give at least two examples of herps adapted to a fossorial lifestyle, as well as traits that characterize them.
Anolis: adaptive radiation of >400 species
Most speciose amniote tetrapod genus.
One species colonized each island in the Caribbean and then radiated into different niches based on microhabitat.
Explain the Anolis ecomorphs and how this represents an example of convergent evolution.
The vast majority of herps are carnivorous
Complete herbivory is very rare among herps
E.g., <1% of all reptiles
Many species are omnivores
Others switch between herbivory, omnivory and/or carnivory during ontogeny
What are the challenges associated with being herbivorous?
Need to eat a LOT to get enough nutrients
Cellulose is hard to break down!
What do most herps eat? Is herbivory common? Why or why not?
Herp: Cane toad (40k eggs per year)
Ocean Sunfish: (300 million eggs per year)
What are the most fecund herp and fish species in the world?
Bd infects amphibian skin cells via zoospore
Amphibian skin exhibits immune response to the pathogen, becoming thicker and more keratinized
This inhibits cutaneous respiration -> animal eventually suffocates
What is the main threat facing amphibian populations, and how does it work?
This ancient reptile species has remained largely unchanged for 60 million years and is famous for its "third eye".
Homeothermic endotherm (passerine)
Poikilothermic endotherm (hummingbird)
Homeothermic ectotherm (fish)
Poikilothermic ectotherm (lizard)
Compare and contrast poikilothermy and homeothermy. Give an example of ectothermic and endothermic poikilotherms and homeotherms.
Selection for or against a phenotype changes with the phenotype's frequency/prevalence in the population.
Side-blotched lizards (genus Uta)
Males have evolved alternative tactics for mating with females
Fish example: scale-eating cichlids!
What is frequency-dependent selection? Give an example in herps that we discussed from class. Extra 100 points if you can name an example in fish!
When does semelparity evolve? When juvenile survival is higher than adult survival, so it makes sense to produce a bunch of offspring all at once before the adult gets killed.
Bet-hedging hypothesis: Can be dangerous to ‘put all your eggs in one basket’
Semelparity is very rare in vertebrates other than the bony fishes (superclass Osteichthyes)
Very rare in herps: Some frogs (genus Hyla, gladiator frogs); A few small lizards (e.g., Labord’s chameleon)
More common in fish:
Compare and contast iteroparity and semelparity, and give an example of a semelparous species of herp and fish. Is it more common in fish or herps?
they are more closely related to birds. Exhibit more parental care than most herps. 4-chambered heart like birds.
How and why are crocodilians different from other herps?
Movable quadrate bones (highly flexible jaw)
Eversible, paired hemipenes
Teeth set in side of jaw periodically replaced
Snakes and lizards are part of this clade, the second largest order of vertebrates (~11,000 species). Name two synapomorphies.
Vomerolfaction: Jacobsen’s organ
Sensitive to high molecular weight compounds
Especially of pheromones
Forked tongue makes this a stereoscopic (3-D) sense
Pit receptors: Infrared detection of thermal radiation!
Have evolved several times in snakes only
labial pits in boas and pythons
loreal pits in pit vipers
Senses temperature via warming of the receptors
Very sensitive –temperature changes of > 0.05 °C
Discuss two ways that snakes use unique sensory systems to detect prey.
Tungara frog and frog-eating bats in Panama.
Explain how the push and pull of natural and sexual selection can shape phenotypes, and give an example in herps from class.
Direct development: Found in a few hundred frog species, Almost exclusively tropical rainforest species. Larvae pass through the tadpole phase within the egg. Allows them to live away from water.
Ovoviviparity in gastric-brooding frogs: Gastric incubation. Females lay eggs which are fertilized externally by males. After fertilization, females swallow eggs, which develop in stomach!!!!
Mouth brooding in Darwin's frog.
Suriname toad: eggs grow out of back!
Give two examples of weird reproductive strategies in herps.
All tortoises are in fact turtles—that is, they belong to the order Testudines or Chelonia, reptiles having bodies encased in a bony shell—but not all turtles are tortoises
Turtle – primarily aquatic, spends most of its time in or near the water. Webbed feet adapted to aquatic lifestyle
Tortoise – primarily terrestrial. Does not have webbed feet, has elephantine legs.Tortoises are generally vegetarians, while other turtles are omnivorous.
Frogs – smooth or slimy skin, more dependent on water.
Toads – bumpy, warty skin. Better able to tolerate xeric (dry) conditions
Frogs also have long legs, longer than their head and body, which are made for hopping. Toads, on the other hand, have much shorter legs and prefer to crawl around rather than hop.
Alligators have a U-spaced rounded snout that is wide and short, whereas crocodiles have a longer pointed, V-shaped snout.
Alligators have an overbite, and so the teeth on the bottom jaw fit into sockets in the top jawline and are concealed. The teeth on the bottom row of a crocodile's jaw, on the other hand, sit on the outside of the mouth and slot into grooves along the top jaw
What are the differenes between:
A turtle and a tortoise
A frog and a toad
a crocodile and an alligator