Herpetology Review: Mating, Development, and Physiology

These flashcards cover key concepts in amphibian and reptile biology, including mating behaviors, reproductive strategies, embryonic development, physiological adaptations, and ecological relationships.

What is the seasonal pattern of mating in amphibians in temperate regions?

Mating is seasonal in temperate regions.

What mediates mating in amphibians?

Mating is hormonally mediated but can also be stimulated by environmental conditions.

What is 'amplexus' in amphibian mating?

Amplexus refers to the various mating positions that vary by species.

Which amphibian group demonstrates complex mating rituals?

Salamanders have complex mating rituals.

Define internal fertilization in amphibians and provide examples.

Internal fertilization is when sperm is introduced into the female reproductive tract; examples include Ascaphus, salamanders, and caecilians.

Define external fertilization in amphibians and provide examples.

External fertilization refers to eggs being laid and fertilized by males; examples include frogs and cryptobranchidae.

What stages occur during embryogenesis in amphibians?

Cleavage, blastulation, and gastrulation.

Describe the cleavage stage of embryogenesis.

Rapid cell division with little growth resulting in a solid ball of cells.

What process involves reorganizing the embryo into a multilayered structure?

Gastrulation.

Define oviparity. What are its costs and benefits?

Oviparity is egg-laying; costs include eggs being exposed and less maternal control, while benefits include lower maternal burden and broad dispersal.

Define viviparity. What are its costs and benefits?

Viviparity is live-bearing; costs include higher maternal energy and fewer offspring, while benefits include increased offspring survival and protection from predators.

How do developing reproductive and amphibian embryos obtain their nutrients?

Oviparous embryos obtain nutrition from yolk (lecithotrophy), while viviparous embryos receive nutrients from the mother (matrotrophy).

What is the pharyngula stage and its significance?

A stage of remarkable similarity across vertebrates indicating shared developmental blueprints.

Define metamorphosis and distinguish between indirect and direct development.

Metamorphosis is a period of rapid morphological change; indirect development involves a larval stage, while direct development does not.

What is the importance of heterochrony in amphibian evolution?

Heterochrony refers to shifts in the timing of development of traits, which can lead to evolutionary changes.

Define the term 'paedomorphosis.'

Retention of juvenile features in adults of descendant species.

What factors influence growth and development rates in herpetofauna?

Genetics, environmental temperature, food availability, and developmental stage.

Distinguish between determinate and indeterminate growth.

Determinate growth stops at sexual maturity, while indeterminate growth continues throughout life.

What are some forms of parental care exhibited by amphibians?

Egg attendance, egg guarding, egg brooding, feeding, and guarding young.

What did Twitty's research on salamander embryos reveal?

It revealed the roles of intrinsic and extrinsic factors in growth regulation.

What is embryonic induction?

The process where one tissue or organ specifies the fate of another.

Distinguish between intrinsic and extrinsic growth factors.

Intrinsic growth factors are genetic, while extrinsic factors are environmental.

What is a self-differentiating system in limb formation?

It is when limb discs can differentiate into limbs regardless of the graft location.

Define an equipotential system in developmental biology.

A system where all parts have equivalent capacity to form a whole structure.

How do amphibian and reptilian epidermises differ?

Amphibians have moist, vascularized skin, while reptiles have dry scales.

What are parotoid glands?

Clusters of poison glands near the head of many toads, producing toxins for defense.

Define proximate causes of aposematic coloration.

Mechanisms like pigment production and neural control of color change.

Define ultimate causes of aposematic coloration.

Evolutionary reasons such as predator avoidance through warning coloration.

How do amphibian eyes differ from mammal eyes?

Amphibians can see well in low light and have UV vision, along with wider fields of vision.

What is the function of a lateral line in amphibians?

It senses pressure changes, vibrations, and movements in water.

What is Jacobson's organ?

An auxiliary olfactory organ for detecting non-volatile compounds, found in squamates.

How do amphibian and reptile respiratory systems differ?

Amphibians use buccal pumping and have a 3-chambered heart, while reptiles have 3 to 4 chambers and use negative pressure ventilation.

What is the circulatory system difference between amphibians and reptiles?

Amphibians have a 3-chambered heart with incomplete separation, while reptiles have partial separation or fully divided hearts.

What are the strengths and limitations of amphibian respiratory/circulatory systems?

Strengths include versatility in breathing; limitations include blood mixing and reliance on moist skin.

What factors affect amphibian habitats due to physiological limitations?

Moist skin requirement limits their habitat to areas with water or high humidity.

What are two purposes of amphibian coloration?

Aposematic for warning signals and cryptic for camouflage.

How are caecilians ecologically different from other amphibians?

Caecilians are fossorial, have elongated bodies, and often lack limbs.

Identify key bone landmarks on a lizard.

Mandible, maxilla, frontal, femur, tibia, humerus, radius, metatarsals.

What adaptation do tree frogs have for their environment?

Adhesive toepads and large tympana for hearing.

How have lizards adapted morphologically to arboreal habitats?

Prehensile tails and adhesive toepads.

What is cranial kinesis?

Movement of skull bones that allows independent jaw movement.

Describe the skull variation in amphibians and reptiles.

Frogs have reduced cartilage and bone fusion, while caecilians have compact, heavily ossified skulls.

What is a urostyle and in which group is it found?

A rod-like bone in anurans (frogs) that supports jumping locomotion.

What are the components of a turtle's shell?

Carapace (dorsal shell) and plastron (ventral shell).

What is CT scanning used for in herpetology?

To produce 3D digital images for studying skeletal anatomy non-destructively.

Define thermosensitive period.

A critical period during incubation affecting sex determination based on temperature.

What is the pivotal temperature?

The temperature at which 50% male and 50% female offspring are produced.

Differentiate between oviparity and viviparity in reptiles.

Oviparity involves eggs, while viviparity involves live-bearing species.

What advantages do shelled reptile eggs provide over amphibian eggs?

Increased protection against microorganisms and desiccation.

What hypotheses explain the evolution of viviparity in reptiles?

Maternal manipulation, cold climate adaptation, hypoxia, and placental feeding.

Explain genetic sex determination (GSD).

GSD involves genes initiating testis or ovary development (e.g., XY or ZW systems).

What is environmental sex determination (TSD)?

TSD is when incubation temperature affects sex development through gene expression.

What are the types of genetic sex determination in tetrapods?

XY (males heterogametic) and ZW (females heterogametic) systems.

Describe the different types of temperature-dependent sex determination.

Type Ia (warm females), Type Ib (warm males), Type II (extreme temps affect both).

What does the Charnov-Bull model explain?

It predicts TSD evolves when fitness of males and females maximized at different temperatures.

Define sexual reproduction in reptiles and amphibians.

Involves two separate sexes with sperm fertilizing the egg.

What is parthenogenesis? Provide examples.

Females produce genetically identical offspring without sperm; examples include whiptail lizards.

What is the distinction of heterochrony in reptiles compared to amphibians?

Reptiles often exhibit peramorphosis, while amphibians show paedomorphosis.

How does parental care manifest in reptiles?

Examples include egg guarding, egg brooding, and transporting hatchlings.

What is the resource allocation concept in reptile reproduction?

The trade-off between reproductive effort and somatic effort for growth and survival.

Define phenotypic plasticity.

Variation in traits due to environmental conditions rather than genetic differences.

What is unisexual reproduction in whiptail lizards?

All-female reproducing through parthenogenesis from hybridization between sexual species.

How do herpetologists study movement in reptiles and amphibians?

Using methods like radio telemetry, drift fences, and mark-recapture.

What processes lead to unisexual whiptail lizards?

Hybridization between two sexual species results in parthenogenetic females.

Name other vertebrates that exhibit unisexual reproduction.

Some fishes, amphibians like gynogenetic salamanders, and parthenogenetic reptiles.

What are the movement purposes for herpetofauna?

Foraging, hydrating, breeding, and thermoregulating.

Differentiate between dispersal, migration, and homing.

Dispersal is unidirectional to unknown locations, migration is bidirectional, and homing returns to a known range.

Define home range versus territory in animal behavior.

Home range is an area for daily activities; territory is a fixed, defended area.

What factors influence home range size?

Species, habitat, food availability, population density, and temperature.

How do herps orient their movements?

Using visual, celestial, magnetic, and olfactory cues.

What mechanisms assist in thermoregulation in herps?

Behavioral (basking, sheltering) and physiological (metabolic heat production).

How does thermoregulation impact herpetological activity?

Activity levels and performance are influenced by optimal temperature ranges.

Differentiate between hibernation and aestivation.

Hibernation is dormancy due to cold; aestivation is due to heat or moisture limitation.

How do amphibians manage osmoregulation?

They absorb water through their skin and require moist surroundings.

What impact does movement have on the energy budgets of herps?

Movement is costly, affecting foraging strategies and energy use patterns.

What morphological adaptations help amphibians conserve water?

Highly vascularized skin and pelvic patches for quick water absorption.

How do amphibians regulate water loss behaviorally?

By adjusting activity patterns and selecting favorable microhabitats.

How do reptiles manage osmoregulation?

They obtain water through consumption and behavioral regulation of activity.

What osmoregulatory challenges differ by environment?

Freshwater, saltwater, and terrestrial environments present various water balance challenges.

What metabolic constraints affect herps?

Size, surface area/volume ratio, temperature, activity levels, and altitude affect oxygen demands.

What is the net cost of transport in herps?

The energy required to move a certain distance, varies by locomotion type.

What is Müllerian mimicry? Provide an example.

Toxic species resembling each other to aid predator learning; e.g., poison dart frogs.

What are microhabitats and their importance?

Small habitat patches that provide thermal buffering and shelter, affecting species distribution.

What does the ectotherm model illustrate?

The relationship between activity, body temperature, and environmental factors.

Define aposematic coloration.

Warning coloration that signals toxicity to potential predators.

What is Batesian mimicry? Provide examples.

Nontoxic species mimicking toxic ones; e.g., scarlet kingsnake mimicking coral snake.

How do evolutionary arms races manifest in herps?

Reciprocal selection dynamics, like increased toxin production in newts and snake resistance.

What is convergent evolution in herps?

Independent evolution of similar traits in unrelated species, like toepads in anoles and geckos.