Podcast
Questions and Answers
Which characteristic is NOT a synapomorphy of amphibians?
Which characteristic is NOT a synapomorphy of amphibians?
What is the primary mode of respiration for salamander species that lack lungs?
What is the primary mode of respiration for salamander species that lack lungs?
Which of these is the correct pairing of amphibian group and its common name?
Which of these is the correct pairing of amphibian group and its common name?
Where is the highest species diversity for salamanders?
Where is the highest species diversity for salamanders?
Signup and view all the answers
What is the approximate total number of amphibian species recognized in February 2021?
What is the approximate total number of amphibian species recognized in February 2021?
Signup and view all the answers
What is a notable characteristic of the integument of amphibians?
What is a notable characteristic of the integument of amphibians?
Signup and view all the answers
Which of the following best describes the global distribution of amphibians?
Which of the following best describes the global distribution of amphibians?
Signup and view all the answers
The presence of nasolabial grooves in some salamanders is associated with what function?
The presence of nasolabial grooves in some salamanders is associated with what function?
Signup and view all the answers
What is a characteristic of the dentition of amphibians?
What is a characteristic of the dentition of amphibians?
Signup and view all the answers
Which of the following describes the typical adult diet of amphibians?
Which of the following describes the typical adult diet of amphibians?
Signup and view all the answers
Which of the following is NOT a typical characteristic of frogs and toads related to their saltatorial locomotion?
Which of the following is NOT a typical characteristic of frogs and toads related to their saltatorial locomotion?
Signup and view all the answers
What is the primary function of the nictitating membrane found in frogs?
What is the primary function of the nictitating membrane found in frogs?
Signup and view all the answers
Arboreal frogs are best characterized by which of the following features?
Arboreal frogs are best characterized by which of the following features?
Signup and view all the answers
What is the main function of the mucous glands in anuran skin?
What is the main function of the mucous glands in anuran skin?
Signup and view all the answers
How do caecilians differ significantly from other amphibians regarding their eyes?
How do caecilians differ significantly from other amphibians regarding their eyes?
Signup and view all the answers
Which structure is NOT associated with salamander reproduction?
Which structure is NOT associated with salamander reproduction?
Signup and view all the answers
What is the main function of the spermatophore during salamander reproduction?
What is the main function of the spermatophore during salamander reproduction?
Signup and view all the answers
What is a key characteristic of the axolotl, belonging to the genus Ambystoma?
What is a key characteristic of the axolotl, belonging to the genus Ambystoma?
Signup and view all the answers
What is a primary difference between 'explosive breeders' and 'prolonged breeders' among anurans?
What is a primary difference between 'explosive breeders' and 'prolonged breeders' among anurans?
Signup and view all the answers
Which of the following best describes the function of a male advertisement call in frogs?
Which of the following best describes the function of a male advertisement call in frogs?
Signup and view all the answers
What purpose does the vocal sac serve in frogs?
What purpose does the vocal sac serve in frogs?
Signup and view all the answers
A frog exhibits the behavior of producing 'whines' when alone and 'chucks' when surrounded by other males. What does this indicate?
A frog exhibits the behavior of producing 'whines' when alone and 'chucks' when surrounded by other males. What does this indicate?
Signup and view all the answers
What is the major difference between external and internal fertilization as it relates to anuran (frog/toad) reproduction?
What is the major difference between external and internal fertilization as it relates to anuran (frog/toad) reproduction?
Signup and view all the answers
In some species of frogs, adult parental care includes the behaviour of transporting tadpoles to water, what is the likely significance of this behavior?
In some species of frogs, adult parental care includes the behaviour of transporting tadpoles to water, what is the likely significance of this behavior?
Signup and view all the answers
Which of the following is a characteristic that both terrestrial and semiaquatic anurans share?
Which of the following is a characteristic that both terrestrial and semiaquatic anurans share?
Signup and view all the answers
What role does the male play in the reproductive process of frogs?
What role does the male play in the reproductive process of frogs?
Signup and view all the answers
How do females of some treefrog species transport their eggs?
How do females of some treefrog species transport their eggs?
Signup and view all the answers
What change signals the start of metamorphosis in tadpoles?
What change signals the start of metamorphosis in tadpoles?
Signup and view all the answers
What is a unique characteristic of generalized tadpoles?
What is a unique characteristic of generalized tadpoles?
Signup and view all the answers
What distinguishes the Darwin’s frog's reproductive strategy?
What distinguishes the Darwin’s frog's reproductive strategy?
Signup and view all the answers
How long does the tadpole development period generally last?
How long does the tadpole development period generally last?
Signup and view all the answers
Which statement best describes the fate of eggs in the Surinam toad species?
Which statement best describes the fate of eggs in the Surinam toad species?
Signup and view all the answers
What feeding strategy can some New Mexico spadefoot toads adopt?
What feeding strategy can some New Mexico spadefoot toads adopt?
Signup and view all the answers
What is the primary method terrestrial amphibians use to absorb water quickly?
What is the primary method terrestrial amphibians use to absorb water quickly?
Signup and view all the answers
What adaptation helps some amphibians become less vulnerable to predation?
What adaptation helps some amphibians become less vulnerable to predation?
Signup and view all the answers
How do many amphibians typically respond to dry nights?
How do many amphibians typically respond to dry nights?
Signup and view all the answers
Which of the following diseases is associated with severe amphibian population declines?
Which of the following diseases is associated with severe amphibian population declines?
Signup and view all the answers
What role do aquaporins play in amphibians?
What role do aquaporins play in amphibians?
Signup and view all the answers
Which of the following features is commonly associated with toxin secretion in amphibians?
Which of the following features is commonly associated with toxin secretion in amphibians?
Signup and view all the answers
How do poison dart frogs acquire their toxins?
How do poison dart frogs acquire their toxins?
Signup and view all the answers
What environmental factor forces Spea multiplicata tadpoles to metamorphose quickly?
What environmental factor forces Spea multiplicata tadpoles to metamorphose quickly?
Signup and view all the answers
What unique phenotype do tadpoles express when they consume fairy shrimp?
What unique phenotype do tadpoles express when they consume fairy shrimp?
Signup and view all the answers
Which structure is mentioned as being extended in some salamanders to deliver toxins?
Which structure is mentioned as being extended in some salamanders to deliver toxins?
Signup and view all the answers
What is a primary disadvantage of cutaneous respiration in amphibians?
What is a primary disadvantage of cutaneous respiration in amphibians?
Signup and view all the answers
What is a significant challenge faced by aquatic amphibians?
What is a significant challenge faced by aquatic amphibians?
Signup and view all the answers
What percentage of amphibian species are currently classified as at risk?
What percentage of amphibian species are currently classified as at risk?
Signup and view all the answers
How do frogs primarily respire while submerged in water?
How do frogs primarily respire while submerged in water?
Signup and view all the answers
What mechanism do frogs use to draw air into their lungs?
What mechanism do frogs use to draw air into their lungs?
Signup and view all the answers
Which statement accurately describes the structure of a frog's heart?
Which statement accurately describes the structure of a frog's heart?
Signup and view all the answers
During cutaneous respiration, where does most of the oxygen come from?
During cutaneous respiration, where does most of the oxygen come from?
Signup and view all the answers
Which process is described as the feeding method for certain species of Caecilian?
Which process is described as the feeding method for certain species of Caecilian?
Signup and view all the answers
What percentage of Caecilian species are known to be viviparous and matrotrophic?
What percentage of Caecilian species are known to be viviparous and matrotrophic?
Signup and view all the answers
What role do mucus glands in frogs play when they are out of water?
What role do mucus glands in frogs play when they are out of water?
Signup and view all the answers
Study Notes
Amphibian Diversity
- Global Amphibian Assessment shows a 60% increase in recognized amphibian species since 1985.
- As of February 2021, there are 8,275 extant amphibian species.
- Anurans (frogs and toads) number 7,301.
- Urodelans (salamanders and newts) number 760.
- Caecilians (Gymnophionans) number 214.
- Species diversity is highest in tropical regions.
- Amphibians are globally distributed, except for isolated oceanic islands.
Amphibian Synapomorphies
- Amphibians possess short, straight ribs.
- Amphibians have highly specialized skin with a high concentration of glands, compared to any other group of tetrapods.
- Gas exchange (cutaneous respiration) primarily occurs through the skin.
- Teeth are pedicellate, meaning teeth are positioned on stalks.
- Salamanders and frogs have distinctly structured ears.
- Adults are carnivorous, with frogs having green rod cells in their eyes.
Order Urodela (Salamanders and Newts)
- Approximately 760 species in 10 families.
- New species are still being discovered in American tropics and southern Appalachia.
- Salamanders are more diverse in North America than Europe and Asia combined.
- Salamander species are distributed holarctically, with some recent entry into South America via the Panamanian land bridge.
- Paedomorphosis is a common trait in salamanders, meaning some remain larval-like into adulthood.
Salamanders
- Thorius pennatulus is the smallest, at 3 cm in total length.
- Andrias davidianus is the largest, at 1.5 meters in total length.
- The largest salamander in the US is the Hellbender (Cryptobranchus alleganiensis), reaching 60 cm.
Family Plethodontidae
- This family comprises over 50% of extant salamander species.
- Lungs are absent in this family, relying on cutaneous and buccopharyngeal respiration.
- Nasolabial grooves facilitate the transfer of chemical cues to the nostrils for sensory input.
- Hyobranchial apparatus allows for tongue projection, a derived trait in some taxa.
Order Anura (Frogs & Toads)
- 7,301 species in 50 families.
- Distribution is worldwide, excluding high altitudes, deserts, and Antarctica.
- Sizes vary considerably, from the smallest leaf climber frog from Cuba ( Eleutherodactylus ) to the giant frog from West Africa.
- Largest anurans can exceed 4+ kg and consume animals as large as rats and ducklings.
More Frogs and Toads
- The most obvious trait is their modification for jumping (saltation).
- Elongated hindlimbs, fused tibia and fibula, and a rigid vertebral column are structural adaptations related to jumping.
- Hind limbs and stiff spine are important for jumping movements.
- Forelimbs absorb landing impacts.
- Binocular vision from large, forward-facing eyes.
- Nictitating membrane protects the eyes.
Types of Frogs
- Common frog types: long legs for jumping, ambush predators, or adapted semiaquatic life with webbed feet for suction feeding.
More Frog Types
- Toads generally have blunt heads, heavy bodies, and short legs with little webbing.
- They are usually wide-ranging predators.
- Camouflage and toxin releases defend against predators.
- Arboreal frogs feature large heads, large eyes, and long legs with distinctive toe pads for gripping.
- Specialized mucus glands generate wet adhesion for clinging to surfaces.
Terrestrial Anurans (Frogs)
- Adult frogs are carnivorous, consuming arthropods, worms, snails, and similar small vertebrates.
- Their tongues are protrusible for catching prey, with a sticky secretion enabled by reversible saliva.
Anuran Skin
- Skin is thin, moist, and not tightly bound to the body.
- Stratified epidermis with soft keratin provides some protection; the layer is periodically shed.
- The dermis has a high gland density, with mucous glands for waterproofing and serous glands for toxin release (commonly toxic).
Order Gymnophiona (Caecilians)
- They are poorly known, with around 214 species.
- They are small to large (20 cm - over 1 meter).
- Most are tropical, excluding Australia and Madagascar.
- Eyes are reduced or covered by skin/bone.
- Only one lung remains (or is vestigial/reduced).
- Skull is reinforced for burrowing.
- Internal fertilization and skin folds (annuli) are common features.
Amphibian Reproduction
- Most amphibians lay eggs that develop into larvae or miniatures of adults.
- Some carry eggs on backs or in pouches.
- Some provide live birth and/or parental care.
- Eggs laid in water may be attached to vegetation, or float freely.
- Some transport tadpoles to water sources.
- Some feed tadpoles.
Salamander Reproduction
- Internal fertilization is common.
- Courtship rituals often involve pheromones.
- Hedonic glands are typically near the chin.
- Sperm packets called spermatophores are deposited by males.
- Spermatheca are storage areas for sperm.
- Fertilization can allow for sperm storage, maintaining viable sperm for months/years.
Salamander Courtship
- Males secrete pheromones from hedonic glands.
- Pheromones are applied to female nostrils or body.
- Some newts display elaborate courtship rituals related to sex.
- Sexual dimorphism is evident in many species.
Salamander Offspring
- Most lay eggs in water as a gelatinous mass.
- Some species show viviparous behavior, giving birth to young or with female parental care.
- European alpine salamanders have offspring that consume unfertilized eggs and are approximately 1/3 the size of the adult.
- Gestation periods range from 2–4 years; depending on species.
Paedomorphosis in Salamanders
- Some salamanders exhibit paedomorphosis, meaning juvenile traits persist beyond maturity.
- Axolotls are a well-known example of this, reaching sexual maturity without undergoing metamorphosis.
Anuran Reproduction
- "Explosive breeders" have a short breeding season, with synchronous egg-laying by all individuals at once (including males and females).
- Breeding is in temporary water habitats.
- "Prolonged breeders" have extended breeding seasons or gradual arrival of individuals, allowing for some sex selection.
Frog Calls
- Male calls advertise territory and attract females.
- Calls often have multiple parts, with a quality component to attract females.
- Group calling (chorus) increases volume.
- Some frogs (like the túngara frog) have intricate and complex calls.
- Some males whine or produce chucks to communicate location/motivation, but it is costly due to energy and attracting predators.
Anuran Reproduction
- External fertilization is common in amphibians.
- Some frogs lay eggs on leaves over water; tadpoles fall into the water.
- Others build floating foam nests above water.
- Many tropical frogs lay eggs near water, waiting for rain to release tadpoles.
- Direct development involves large eggs with rapid tadpole-to-frog development.
Parental Care in Frogs
- Some frog species show parental care, with both male and female participation in guarding eggs and tadpoles.
- Some species of frogs transport tadpoles to water bodies.
- Females of some tree frog species carry eggs, and some of the species of frogs carry eggs in pouches.
General Anuran Life-History Strategy
- Generalized tadpole features (long tail with a complete fin, internal and external gills).
- Tadpoles' mouths may be specialized for herbivory or carnivory.
- Striking metamorphosis from tadpole to adult.
- No salamander-like paedomorphosis in anurans is found.
Metamorphosis of a Tadpole
- Tadpole metamorphosis is characterized by a two-stage life cycle.
- Changes are stimulated and controlled by hormones from the anterior pituitary gland, specifically thyroxine.
- Physical changes, starting with degeneration of the tail, lead to the larval-to-adult transition.
Anuran Life-History Strategy
- Frogs and toads occupy various habitats and feed on various items.
- Breeding takes place in temporary bodies of water.
- Eggs are often laid in large masses and hatch in a short time.
- Metamorphosis in tadpoles is quick, before pools dry.
- Some species have phenotypic plasticity in response to environmental conditions, allowing them to adapt to new food sources (like insect consumption).
Caecilian Reproduction
- Internal fertilization is typical.
- Intromittent organ is present.
- Most viviparous and/or matrotrophic.
- Some species provide uterine milk to develop young, supplying nutrients after the yolk is gone.
- Dermatophagy is a feeding method with some species.
Respiration
- Amphibians depend on cutaneous respiration for gas exchange.
- Moist skin is needed for cutaneous respiration. Skin cannot increase respiratory surface with physical activity.
- Lung respiration is also available in some, especially in more terrestrial anurans, allowing for a more efficient method of gas exchange.
- Direct transition into the adult phase relies primarily on lung respiration when anurans are completely terrestrial.
Blood Flow
- Heart has a septum separating atria, but ventricles are undivided.
- Deoxygenated/oxygenated blood are kept slightly separate and travel to their designated locations based on oxygenation state.
- Blood flow is modified during cutaneous respiration or pulmonary respiration.
- Blood passing through the lungs or skin is oxygenated, then distributed throughout the body.
How Do Frogs Survive in Dry Conditions?
- Some frogs stay underground and come out only after it rains.
- They tend to reproduce during periods of more frequent rainfall.
- Adaptations involve behaviors and skin modifications.
- Skin may be less permeable to water in some species, retaining more body moisture.
Water Intake
- Amphibians do not drink water in the traditional sense; they take it through osmosis.
- Aquatic amphibians have mechanisms to handle osmotic changes from water influx.
- Terrestrial amphibians use the pelvic patch that absorbs water quickly, helped by aquaporin actions.
Mucus, Toxins, and Venom
- Some frogs and salamanders use mucus glands for defense.
- Sticky mucus traps or deters predators; others have poison glands in their skin.
- The secretions are irritating or toxic, deterring predation.
- Some species are poisonous as a means of defense against predators or competitors.
Declining Amphibian Diversity
- Many are classified with risk levels of some concern.
- Diseases are from invasive frog species that are spreading and causing problems.
- Chytridiomycosis, caused by a fungus, is a serious threat, decimating amphibian populations and causing high mortality rates in certain species.
Important Roles of Amphibians to Human Welfare
- Amphibians serve as models in teaching (biodiversity, communication, ecology, etc.) and research (toxicology, medicine, ecosystems).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the fascinating characteristics of amphibians, including respiration methods, diversity, and anatomical features. This quiz covers various aspects of amphibian biology, such as their integument and dietary habits. Challenge yourself to identify key traits that define these unique creatures!
