Vertebrate Zoology Exam 2

What is Ichthyostega

An early tetrapod used as evidence in the transition from fish to amphibian-like vertebrates

What evidence supports fish-to-amphibian evolution

Fins to limbs/digits, aquatic to terrestrial adaptations, gills to lungs/skin respiration, one occipital condyle to two, and reduction in skull bones

Why is a simple fish-to-amphibian ladder an oversimplification

Evolution is branching rather than a straight ladder, and transitional organisms are not necessarily direct ancestors

what are zygrapophyses

projections of vertebrae that help stabalize and articulate the vertebral column

how many occipital condyles do amphibians have

two

what is the hymomandibular?

a fish skeletal element associated with the jaw and gill-support system that was modified during vertebrate evolution

What is autostylic jaw suspension

a condition in which the upper jaw is attached to the skull rather than being suspended primarily by the hyomandibular

whata are the two major layers of amphibian skin

epidermis and dermis

what is the stratum corneum

the outer, keratinized epidermal layer that is continually sloughed

What is the stratum spongiosum

the superficial layer of the dermis contained chromatophores

what is the stratum germinativum

the deeper epidermal layer that replaces cells of the stratum corneum

What is the stratum compactum

the deeper dermal layer containing structural proteins, nerves, and vascular supply

How does amphibian skin differ from fish skin?

Amphibian skin has keratinized surface layers, multicellular glands below the epidermis and practically no scales.

what are setae

epidermal structures found on toe pads of some hylid frogs

What are spades

epidermal modification used for digging

what are nuptial pads

thickened areas, often at the base of the male’s thumb (pollux), used to grip females during breeding

what are rasping lips

specialized, temporary oral structures found in the larval stage

Chromatophores

pigement-containg cells in the dermis responsible for much amphibian coloration

melanophores

chromatophores containing black or brown pigment

lipophores

a type of pigment cell or chromatophore that contains yellow, orange, or red lipochrome pigments

chemical coloration

color produced by pigments in pigment cells

guanophores

chromatophores containing white, guanine-like purines

what is structural coloration

color produced by light interacting with skin layers

mucous glands

modified glands in some salamanders associated with pheromonal functions

serous glands

amphibian poison glands producing granular secretions

what are granular alkaloid poisons

ampphibian glad secreations that can affect cardiovascular or nervous systems

parotid gland

a concentration of poison-producing serous glands

what is the difference between poison and venom

poison harms through exposure;venom is actively delivered

where is amphibian poison produced

in skin glands, serous/parotid glands

whire is reptile venom delivered

through specialized teeth or other delivery structures

what is a neurotoxin

a toxin that affects the nervous system

cytotoxin

toxin that damages cells or tissues

hemolytic venom

venom that damgage red blood cells

proteroglyph

a snake with fixed fangs, characterisitic of cobras and coral snakes

venom from proteroglyphs

primarily neurotoxic venom

what is a solenoglyph

a snake with hinged fangs that fold against the upper jaw

what type of venom can solenoglyphous have

cytotoxic, hemolytic, and neurotoxic components

what special sensory structure do pit vipers have

heat sensing pits

gilatoxin

a mild venom from gila monsters and beaded lizards

what is a nictitating membrane

a protective membrane covering an amphbian eye

how does the anuran lens differ from other amphibians

anuran lenses can move back and forth

tympanic membrane

the membrane involved in hearing; it is larger in male ranidae

do salamanders have external ears

no

what covers a snake’s eye

a scale membrane that sheds with the body scales

do snake have eyelids

no

vomeronasal organ

a chemical-sensing organ also called Jacobson’s organ

Why do snakes have forked tongues

to collect chemical information from different directions

olfaction

the sense of smell

how can snakes navigate

using olfaction, a sun compass, and landmarks

what are explosive breeders

amphibians that breed within a short period, often 2-3 days

interference competition

direct competition among males, such as physical interference

What are prolonged breeders

amphibians breeding over several months

How do prolonged breeders differ socially from explosive breeders

males are more spaced out and may call for several months while defending territories

what are vocal sacs

structures that receive air and help produce amphibian calls by expelling air through the larynx

what reproductive pattern is associated with Pseudacris crucifer

large egg masses

what reproductie pattern is associated with ambystoma sp.

single egg attachment

what reproductive pattern is associated with plethodon cinereus

terrestrial reproduction

what reproductive pattern is associated with Hyla versicolor

treetop reproduction

what does oviparous mean

producing eggs that develop outside the mother’s body

which reptiles in the lecture are all oviparous

turtles and crocodilians

what reproductive modes occur in snakes and lizards

both oviparity and ovoviviparity

what is ovovivipary

eggs develop inside the mother without a fully calcified shell; the young are retained until hatching or near hatching

what evidence indicates maternal gas/ion exchange in ovovivipary

the oviduct and yolk sac can be highly vascularized

what is a hemipenis

one of a paired set of male reptile copulatory organs

where is the hemipenis located

at the base of the tail just behind the cloaca

how does a hemipenis function

the male everts one organ and sperm travels along it groove to the female cloacal opening

phragmosis

flattening of the skull associated with amphibian skull structure

acrodont dentition

teeth attached to the edge of jawbones without sockets

pleurodont dentition

teeth socketed in the jawbone

genioglossus

a large tongue muscle involved in projecting the frog’s tongue

what do intermandibular muscles do in frog feeding

the contract with the genioglossus to help project the tongue forward

where is the tongue attached in most amphibians

posteriorly; in anurans it tends to be attached anteriorly

how does a frog capture prey with its tongue

the genioglossus and intermandibular muscles contract, projecting the tongue forward

how does trunk musculature change with amphibian locomotion

it changes from primarily providing locomotion to providing more support

how are salamander limbs modified

they are reduced in size

how are anuran limbs modified

the are elongated

how many front digits do amphibians have at most

four

how many back digits do amphibians have at most

five

what limb modification occurs in Hylidae

specialized modification associated with their locomotion and toe pads

which family has the greatest jump distance relative to body size

hylidae

which family has the greatest absolute jump distance

ranidae

which genus has teh samllest jump relative to body size in the lecture

bufo

what is lateral undulation

the standard snake movement in which waves pass through the body and the animals pushes against objects on different sides

what is rectilinear motion

straight-line snake movement produced by sequential muscular movement rather than large body waves

what is concertina motion

snake movement using alternating anchoring and extension of body sections, especially in confined spaces

what is sidewinding

snake movement in which the body moves sideways while only portions of the body contact the ground

what are automatic vertbrae

tail vertebrae at fracture zones that allow a reptile to release its tail as an antipredator response

can a reptile regenerate a tail after it breaks at an automatic fracture zone

yes, regeneration can occur, but the regenerated tail does not have the same original pattern

what happens if the tail breaks between vertebrae rather than at the fracture zone

the tail does not regenerate

what respiratory surfaces do amphibians use

lungs, gills, and skin; some respiration also occurs through the buccal cavity

why is skin respiration important in amphibians

the relative importance of non-pulmonary respiration is associated with variation in amphibian heart structure

what determines variation in amphbian heart structure

the relative importance of non-pulmonary versus pulmonary respiration

how does the terrestrial caudata heart differ

the lecture states there is no interatrial septum and no pulmonary vein, with chamber containing blood of similar oxygenation

brumation

a period of reduced activity during cold conditions

how do some amphibians survive freezing temperatures

some accumulate glucose as a cryoprotectant; rapid cooling can trigger increased liver phosphorylase activity.

which amphibians are noted as cold tolerant in the lecture?

lithobates sylvaticus, Hyla versicolor, Pseudacris crucifer, and Pseudacris triseriata

what are xeric adaptations

adaptations that help an animal tolerate dry conditions or conserve water

basking poikilothermy

behavioral regulation of body temperature by moving between warmer and cooler environments

what preferred body temperature range is given for reptiles

about 28-34˚C

what role does the hypothalamus play in reptile termoregulation

it helps detect body temperature relative to the preferred temperature and triggers movement toward warmer or cooler sites