FNR 24150 Final Exam (Herp Lectures 8-14)

closeness, dispersal

rate of gene flow to a function of the ______________ of the population and the _____________ tendency of the species

classical biological concept

genetically distinctive populations of individuals isolated reproductively from all other populations

subspecies

population of a particular region genetically distinguishable from other such populations and capable of interbreeding with them
Ex: prairie racerunner and six-lined racerunner

cline

gradual and continual change in a character by a series of populations or throughout the range of a species
- usually along a geographic or environmental gradient
- Ex: plastral markings in painted turtles

latitudinal changes

changes in body weight (Bergmann's Rule) and changes in body color

1. climate
2. availability and access to resources
3. dispersal abilities

3 major factors that influence geographic distribution of amphibians and reptiles

feeding, thermoregulation, and predator avoidance

3 purposes for daily movement

more (breeding, hibernation, and habitat utilization)

seasonal movement is _________ extensive

dispersal

movement outward from the home range, often implies colonization (undirected movement to locations unknown by the dispersing animals)

benefits of dispersal

1. minimizes intraspecific competition
2. increased contact with individuals of other species/unrelated
3. decreased inbreeding

costs of dispersal

1. lacking food resources and possibly shelter
2. increased unknown predators (increased predation risk)

piloting

ability to recognize land marks within home range

compass orientation

sense of direction, independent

true navigation

internal map, ability to move toward any location

visual orientation

using polarized light to navigate

celestial orientation

using stars to navigate

visual, wave, magnetic

Green Seas Turtles use ________ cues, _______ orientation, and ____________ orientation to navigate

stars, moon

Using _________ and _________ helps Green Sea Turtle hatchlings find the ocean when on the beach

Green Sea Turtles use _________ orientation to move away from shore into the sea

magnetic

Once Green Sea Turtle hatchlings are deep into the ocean, they use ____________ orientation to help with navigation

Sea Turtles orient use waves

Experiment where:
- turtles were tethered inside a floating orientation arena
- results:
> turtles swam into waves when waves were present
> when waves were absent, turtles didn't know which way swim (random)

Sea Turtles detect magnetic fields

Experiment where:
- turtles were tethered inside a floating orientation arena
- half the turtles swam under Earth's magnetic field, the other half swam in a reverse magnetic field
- results:
> turtles swimming in Earth's magnetic filed swam east to northeast (normal direction they follow off shore)
> turtles tested in reverse filed swam the opposite direction

larger (seen in the Spiny Lizard)

males tend to have __________ home ranges than females

males

do males or females tend to have a more dynamic home range throughout the year?

expensive

defense is usually very _____________

turtles (freshwater)

what herp group tends to have the largest home ranges?

caudates (anurans are 2nd)

what herp group tends to have the smallest home ranges?

territorial defense

When an animal or group of animals protects its territory from others by marking it with pheromones

site defense

reducing the likelihood of attack against a particular site, a male defends one "thing" (rock, basking log, food item nesting site)

True

T or F: site defense is more common than territorial defense

insects

frogs and salamanders feed on...

plants and animals (vertebrates and invertebrates)

turtles feed on...

animals (vertebrates and invertebrates)

squamates feed on...

hyoid bone

piece of cartilage that serves as a rigid base of the tongue

chameleons

the hyoid bone is seen in...

Opisthoglyph

rear-fanged snakes, angled backward utilized to inject venom into the puncture wound

Proteroglyph

forward grooved fangs in front, hollow filled with neurotoxin (seen in Common Cobra)

Solenoglyph

hinged fangs, fold against roof of mouth, hollow filled with hemotoxin (seen in Vipers)

ambush (sit-and-wait) and active (wide foraging)

2 foraging modes

ambush foraging

- less energy spend on searching
- more energy spent on capturing prey
- specialized eyesight and organs
- rely on cryptic coloration

active foraging

- searching for prey
- visual and chemical cues used for prey detection

prey availability, predation risk, social interactions, habitat structure

4 external factors influencing foraging behavior

hunger level, amount of learned experience (coupled with age), genetics, dietary preference

4 internal factors influencing foraging behavior

sensory limitations, morphological characteristics, physiological characteristics (too cold/too warm), behavioral

4 phylogenetic factors influencing foraging behavior

visual prey detection

- used by ambush predators
- need large, developed eyes
- discriminate prey based on size and shape
- binocular perception
- most align their head or entire body axis with that of prey before attacking

olfaction

- epithelium in nasal cavity detect airborne odors

- long distance detection system

- main sense of salamanders and lizards

vomerolfaction

- sensation to high molecular weight compounds which are transported to oral and nasal cavities via the snout or tongue

- short distance detection system

- main feeding sense in salamanders, lizards, and most snakes (bifurcated tongue in snakes provide directionality of info)

taste

- helps distinguish food items from non-food items (accept and swallow or reject and spit out)

Jacobson's organ

Sense organ on snake's roof of mouth which detects airborne chemicals
- located behind nose and infront of eyes
- when tongue is retracted back into mouth, the split tongue fits into the grooves in the organ which lies along nerves
- nerves transmit info to the brain

tactile prey detection

mechanoreceptors in skin
- in several species, flaps of skin are highly innervated and also help
- Ex: lateral line system in aquatic amphibians

thermal prey detection

IR is sensed in nerve endings in the skin of the head which are located inside pit organs
- pit organs provide a binocular perception field
- most effective for nocturnal species that feed on mammals and birds

1. biting/grasping
2. constriction (boas and pythons)
3. injected venom
4. filter feeding (tadpoles, large buccal cavities)
5. suction feeding (common in snapping turtles and hellbenders)
6. projectile tongues

6 prey capturing techniques

1. feeding adaptations of animal
2. size of animal and prey-capturing methods
3. habitat
4. relative abundance and size of prey available at the time of feeding

food habits depend on...

communication

transfer of info from signaler to a reciever

visual communication

communication through body movement and colors

acoustic communication

communication through sound (vocalization, rubbing body parts together)

chemical communication

communication through glandular secretion odors, well developed in salamanders, lizards, and some snakes

tactile communication

communicating through touching

locate and message mates in complex environment

benefits of communication

ambystomatids

the cloaca nudging waltz is seen in...

chemical (pherohormones produced by courtship glands), tactile (nose-tapping, biting, slapping, rubbing)

salamanders use ____________ and ____________ cues to communicate

plethodontids

the tail straddling waltz is seen in...

acoustic (calls), visual (bright coloration)

frogs use ____________ and ____________ cues to communicate

advertisement

type of frog call to attract conspecific

reciprocation

type of frog call females use to respond to males (rare)

release

type of frog call used when male is being amplexed by another male

distress

type of frog call used as a predator alarm

visual (head bobs), tactile (biting, tickling, ramming), chemical (cloacal secretions, special glands on the bridge of their shells)

turtles use ____________, ____________, and ___________ cues to communicate

visual (dewlap coloration), chemical (pherohormones), tactile (tongue flicking, body scratching)

lizards use ____________, ____________, and ____________ cues to communicate

tactile

snakes use __________ cues to communicate

interspecific competition

competition between members of different species

intraspecific competition

competition between members of the same species

evaporative loss (helps maintain moisture during cold months)

snakes congregate during hibernation to minimize...

breeding aggregations

collective calling to attract female to breeding site

predation

____________ is the greatest cause of mortality

escaping detection

predator avoidance technique: not being present when a predator is searching for prey

crypsis and immobility

predator avoidance technique: resemble a random sample of certain aspects of the environment (usually immobile)
- Examples:
1. blending in
2. polymorphic coloration
3. changing body shape (Vine Snakes and Surinam Toads)

aposematic coloration

predator avoidance technique: bright coloration in animals that produce noxious or lethal chemicals from skin glands (Poison Dart Frogs)

postural warning

predator avoidance technique: assuming several defensive postures to "scare" predators
- Unken Reflex in Fire Belly Toads
- Large red eyes in Red-eyed Tree Frog

batesian mimmicry

predator avoidance technique: occurs when a nontoxic species mimics a toxic or protected one
Ex: Northern Scarlet Snake mimics the Eastern Coral Snake
Ex: Amazonian Leaf Litter Frogs
Ex: Red morph of Redback Salamander mimics Red Eft stage of Eastern Newt

Mullerian mimicry

predator avoidance technique: both potentially dangerous species resemble each other (both species are the model and mimic)

escaping

predator avoidance technique: running away or hiding:
1. Skin, armor, and spines
2. Chemical defense
3. Death Feigning
4. Tail Displays and Autonomy
5. Schooling

Microparasites and Macroparasites

agents of infectious disease

Microparasites

- reproduce inside of host
- bacteria, viruses, protists, and fungi

Macroparasites

- reproduce outside of host
- helminths and anthropods
- intensity-dependent pathology

extinction

parasites rarely drive their hosts to _____________

inbreeding, stochasticity

____________ and ____________ drive disease-induced extinction in small populations

1. Chytrid Fungus
2. Ranivirus
3. Rib Virus (Ribeiroia ondatrae)

3 parasites of conservation concern in herps

Chytrid Fungus

a pathogenic fungus that has a a devastating impact on frogs
- attacks keratinized tissue (mostly in adults)
- causes lethargy, paralysis, skin lesions, loss of pigment
- leads to impaired osmoregulation and cutaneous respiration

Ranivirus

a pathogenic fungus infecting ectothermic vertebrates (herps and fish)
- most virulent forms: Ambystoma Tigrinum Virus (ATV) and Frog Virus 3 (FV3)
- causes organ destruction (liver, spleen, kidney)
- signs of death: edema, redness, hemorrhages, ulcerations
- mosquitos infect lethargic turtles

Rib Virus

a parasitic fluke (platyhelminths) that targets limb tissue
- cycle of deformity:
1. aquatic snails
2. Amphibians

eutrophication

A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria

biodiversity crisis

loss and reduction in diversity at all levels (genetics --> ecosystems)

extinction

rate has growth exceeded the "normal" historical rates

1. habitat modification, fragmentation, and loss
2. harvest
3. introduction of exotic species
4. management tools

human impacts on herp conservation

habitat alteration/fragmentation and increased mortality due to road kills (leads to skewed sex ratios)

consequences of human-influenced habitat modification

commercial exploitation of herps

1. Consumption (frog legs)
2. Luxury Trade (American Caimans for leather)
3. Pet Trade (box turtles)

introduction of exotic species examples

1. Black and Norway Rates --> great impact on islands (lizards, tuataras, tortoises)
2. Domestic Cats --> damage in suburban and rural areas
3. Herbivores (goats and rabbits) --> change vegetation

leapord

American bullfrogs reduced ___________ frogs in California by 33% and in Arizona

minimum viable population (MVP)

minimum area required for a population or species to survive