herpetology final exam

cranial kinesis

mobility of skull

vomeronasal organ

detects pheromones in roof of mouth

Streptostyly

increased jaw mobility due to elongate and mobile quadrate bone

Strike-Induced Chemosensory Searching

elevated tongue flickering after striking and releasing prey to follow the scent trail

toxicofera

toxic clade of lizards that all possess genes for venom production

Duvernoy's gland

produces venom in colubrid snakes

associated with posterior teeth

Aposematism

warning colorations that advertise defenses

unken reflex

exposure of ventral surface during predatory encounters

tail autonomy

fracture planes in vertebrae facilitate tail loss; specialized muscles fracture tail and restrict blood vessels

home range

area used in daily activities

dispersal migration

movement of juveniles away from birth area

territory

a fixed area actively defended against intruders

pheromone

chemical message that triggers behavioral responses in other individuals

halfway technology

techniques that address symptoms of environmental degradation after damage has occurred instead of finding root causes

IUCN red list

conservation status of species based on population trends, population sizes, and threats

Chytridiomycosis

fungal infection in amphibians

intraspecific factors of diet variation

ontogeny and sexual differences; nutritional effects

what organisms have ontogeny and sexual differences in diet variation

common in gape limited predators such as crocodilians and snakes

nutritional effects in diet variation

herbivorous reptiles are more carnivorous as juveniles to meet protein requirements for growth

what organisms have nutritional effects in diet variation

iguanas and turtles

interspecific factors in diet variation

phylogeny and specialization

ontogenetic diet shift

predators select larger prey types as they grow

why is herbivory a specialization in ectotherms

plants are abundant but impossible to digest without symbiotic microbes

projectile feeding mechanisms

projectile tongue with sticky expanded tip captures prey

three independently derived examples of projectile feeding

salamanders, anurans, chameleons

cranial kinesis as a feeding specialization

independent movement of skull parts increases flexibility and facilitates swallowing large prey

constriction

snake coils tightly around prey impeding circulatory fucntion

venom delivery systems

rear and front fanged systems

rear fanged venom delivery

require chewing the prey to inject the venom

front fanged venom delivery

inject toxins through hollow fangs in a fast strike

foraging modes

ambush and avtive

ambush foraging

sedentary foraging from a fixed location; sometimes use lures to attract prey

who uses ambush foraging

Chunky, cryptic, large mouth

active foraging

search over a large area; exploit immobile or hidden prey

who uses active foraging

fast, agile and streamlined; eat small prey

main five types of enzymes in venom

proteolytic, acetylcholinesterase, thrombin like, hyaluronidase, phospholipase

proteolytic enzymes

digest tissue causing hemorrhagic necrosis

thrombin like enzymes

interfere with blood clotting

hyaluronidase

degrades connective tissue; enhances spread of venom

phospholipase

damages nerve cells; interferes with motor function

Acetylcholinesterase enzyme

interrupt neuromuscular transmission; cardiac function and respiration

polypeptides

nonenzymatic proteins that interfere with nerve cell function

types of polypeptides

crotactin, cobrotoxin, viperation

crotactin

paralysis and respitory distress

cobrotoxin

heart muscle paralysis

viperatoxin

vasodilation and cardiac failure

functions of snake venom

predation and defense

predation functions of snake venom

immobilization, death, facilitate relocation, improved digestion

defense function of snake venom

debilitating experience for snake predators

venom chemistry correlation with prey types

elapids get neurotoxin and viperids get hemotoxin

neurotoxin

immobilize elongate prey

hemotoxin

digestion of bulky prey

what type of prey do snakes give more venom to

larger prey and ectothermic prey

how does a sophisticated VDS affect prey size consumption

consume largest prey; 1.5:1 ratio

what do ontogenetic changes in toxicity reflect

changes in diet with snake body size

types of defense mechanisms

crypsis, aposematic signals, mimicry, inhibitory tactics

crypsis

avoid detection by background matching

example of crypsis

copperhead snake

aposematic signals

advertise inedibility

mimicry

resemblance to an inedible organism

inhibitory tactics

defensive weapons

example of mimicry

scarlet king snake pretending to be coral snake

example of aposematic signals

rattlesnake warning tail

example of inhibitory tactics

hissing, defensive coil, playing dead

treatment for snakebite

antivenom; keep bitten extremedy elevated

difference between annual snake bite related deaths in united states and southeast asia

us has less than ten deaths; se asia has up to 50k

types of communication signals

visual, chemical, auditory, tactile

visual communication

requires close proximity of signaler and receiver

chemical communication

persistent message consistent over time and distance

auditory communication

functions over distance and easily modified

tactile communication

used for social interactions requiring close contact

communication used by caecilians

chemical cues; sensory tentacle connected to vomeronasal organ

communication used by anurans

auditory signaling with some visual and chemical cues

vocalization categories

advertisement, reciprocation, release, distress

three types of advertisement calls

courtship, territorial, encounter

courtship call users

male attract female

territorial call used by

territory owner

encounter call used between

males in breeding choruses

reciprocation call

females responding to males

release call

males mistakenly amplexed by another male

distress call

used when captured by predator

what signals do salamanders use

chemical, visual, and tactile

plethodontids coutship signals

males produce pheromones delivered to females with physical contact

newt courtship signals

tactile, chemical and visual

crocodilian signal uses

auditory for long range communication and visual displays for mating and agression

turtle communication

visual for social, chemical for identification, and tactile for courtship

dominant signal type of iguanas

visual

dominant signal for scleroglossan lizards

chemical

snake communicartion

chemical dominates and tactile in social interactions

home range sizes influenced by

body size, energetics, reproductive condition, food availability, access to mates

how does being pregnant affect home range size

pregnant females restrict sptial use to favorable gestation sites

high prey densities result in ____ home ranges

smaller

why do males need a bigger homerange

looking for mate

main threats to amphibians and reptiles

climate change, habitat destruction, predation, disease, invasive species

environmental threats to amphibians

uv radiation, environmental estrogens, pesticides and herbicides

what percent of reptiles are threatened with extinction

21

what percent of amphibian species are threatened with extinction

41

what percent of crocodilians are threatened with extinction

50

what percent of turtles are threatened with extinction

58

what percent of squamates are threatened with extinction

20