Herpetology exam 3

According to Newton's 3rd Law of Motion, what are the two forces involved in locomotion?

Muscular force and reactive force.

In the context of locomotion, what are the two components of the reactive force?

The vertical component and the propulsive component.

What are the three essential parts of a lever system in biological locomotion?

The fulcrum, the out-lever (with out-force), and the in-lever (with in-force).

Why does lateral bending of the vertebral column increase stability during quadrupedal walking?

It helps maintain the center of mass within the triangles of support created by the limbs.

How does the muscle action of salamanders differ between swimming and walking?

Swimming involves undulatory movement of the body, whereas walking involves limb-driven movement with lateral bending of the vertebral column.

What is the function of the joint between the sternum and the coracoid in lizards?

It increases the stride rate during locomotion.

Why are bipedal lizards classified as 'dynamic bipeds'?

They only maintain bipedalism while in motion, relying on momentum and dynamic balance rather than static posture.

How is lateral undulation limited in turtles?

It is restricted by the rigid structure of the shell (carapace and plastron) which limits vertebral flexibility.

What are the primary segments of the anuran hindlimb and pelvis involved in jumping?

The pelvis, femur, tibiofibula, and the elongated tarsal bones.

What are the three main locomotor muscle groups in snakes?

Epaxial muscles, hypaxial muscles, and ventral muscles.

How do snakes utilize pivot points during lateral undulation?

They push their body against irregularities in the substrate to create pivot points, which generate the force necessary for forward motion.

How does concertina locomotion function in snakes?

The snake anchors the posterior part of its body while extending the anterior part, then pulls the posterior part forward, repeating the cycle.

What is the primary purpose of sidewinding locomotion in snakes?

It allows movement across loose or shifting substrates (like sand) by minimizing surface contact and maximizing traction.

How does rectilinear locomotion differ from lateral undulation?

Rectilinear locomotion involves moving in a straight line using ventral scales and muscles without lateral body bending.

How does an airfoil generate lift in aquatic environments?

By creating a pressure differential between the upper and lower surfaces of the appendage as water flows over it.

What is the difference between undulatory and oscillatory swimming?

Undulatory swimming involves wave-like body movements (e.g., snakes), while oscillatory swimming involves flapping or rowing appendages (e.g., turtles).

What is the function of metatarsal tubercles in burrowing anurans?

They act as 'spades' on the hind feet to facilitate digging into the substrate.

How does internal concertina locomotion work in caecilians?

The skin moves independently of the vertebral column, allowing the animal to anchor its skin against the burrow walls while the body moves forward inside.

How does head shape correlate with burrowing strategy in amphisbaenians?

Head shape (e.g., spade-shaped, wedge-shaped, or rounded) is specialized to minimize resistance based on the density and type of soil being penetrated.

What is the difference between wet and dry adhesion in climbing herpetofauna?

Wet adhesion (frog toe pads) relies on surface tension and mucus, while dry adhesion (gecko toe pads) relies on van der Waals forces via microscopic setae.

What is the primary distinction between parachuting and gliding?

Parachuting is a passive descent that slows the rate of fall, while gliding is an active, controlled flight that allows for horizontal distance.

What is Newton's first law of motion?

A body at rest will remain at rest, and a body in motion will remain in motion unless acted on by an external force.

What is the mathematical formula for Newton's second law of motion?

Force (F) equals mass (m) times acceleration (a), or F = m x a.

What is Newton's third law of motion?

For every action there must be an equal but opposite reaction.

Which animal groups are characterized by locomotion using sprawling limbs?

Most salamanders, lizards, and to a lesser degree, crocodylians.

What is the typical lateral footfall pattern in most tetrapods?

RH, RF, LH, LF (Right Hind, Right Fore, Left Hind, Left Fore).

How do salamanders move while swimming?

They use lateral undulations, where a traveling wave passes down the trunk from the front of the body to the tail.

How do lizards enhance their stride length during locomotion?

By utilizing substantial lateral bending of the trunk.

What anatomical feature characterizes the pectoral girdle of lepidosaurs?

A tongue-in-groove sliding joint between the medial sternum and the paired coracoid bones.

What defines a 'dynamic biped'?

An animal capable of supporting itself on two legs only while it is running.

What anatomical specializations allow for bipedalism in certain lizards?

Long hindlimbs, short forelimbs, a robust sacral articulation, and a short presacral vertebral column.

What is the primary effect of the anatomical specializations in bipedal lizards?

A posterior shift in the center of gravity.

How does crocodylian limb movement differ from that of lizards?

Crocodylian limb movement is more nearly parasagittal, meaning the limbs move in a plane parallel to the vertebral column.

What are two common types of terrestrial locomotion used by crocodylians?

The high walk and a bounding gait.

Why can't turtles shift their center of gravity by bending their vertebral column?

Because their limb girdles are enclosed within the shell.

How do turtles move their limbs given the constraints of their shell?

The humerus and femur can only move within the limits of the openings between the carapace and plastron.

What strategy do turtles use to move their center of gravity forward?

They lift the hindfoot before placing the contralateral forefoot, allowing the center of gravity to fall forward before the forefoot catches the substrate.

What is the term for jumping locomotion?

Saltation.

What anatomical features allow anurans (frogs) to jump effectively?

A short, relatively rigid vertebral column and greatly elongated hindlimbs.

Which muscles are involved in the anatomy of a frog's jump?

Semimembranosus, semitendinosus, gracilis major, gluteus maximus, and cruralis.

In terrestrial locomotion, what is the combination of movements used by salamanders?

Lateral undulations combined with limb movements.

What is functional limblessness in Squamata?

A condition where limbs have evolved to be no longer used effectively for locomotion, occurring at least 25 times in the group.

How does concertina locomotion function?

A portion of the body is anchored against the walls of a burrow or surface while another portion is moved forward.

Why is sidewinding advantageous on shifting substrates?

Forces are directed vertically against the substrate, which prevents the slipping that occurs when pushing at an angle against loose material like sand.

How does rectilinear locomotion work?

Both sides of the body act synchronously, sequentially contracting and relaxing to draw the body forward in a straight line.

What are the primary advantages of aquatic locomotion compared to terrestrial?

Water provides greater support against gravity and its density allows for the generation of substantial reaction forces.

How do aquatic snakes differ from terrestrial snakes in their swimming?

They use regular axial waves that increase in amplitude posteriorly and often possess modifications like a laterally compressed tail to increase surface area.

What is the 'kick and glide' system in oscillatory swimmers?

A method using synchronous extension of large, webbed hindfeet to provide propulsion while minimizing side-to-side movement.

How do sea turtles generate lift-based propulsion?

They adjust the angle of their elongate, winglike forelimbs during both the downstroke and upstroke to generate a forward component of lift.

What are common morphological specializations of fossorial squamates?

Smooth skin, reduced scale counts, and secondary bone contacts in the skull to increase rigidity.

How do burrowing squamates use internal concertina locomotion?

The skin is loosely connected to the axial muscles, allowing vertebral flexion to press the body against tunnel walls for stability and penetration.

What adaptations do sand-swimmers have to move through loose sand?

Wedge-shaped heads, countersunk lower jaws to prevent ingestion of sand, and smooth scales to minimize friction.

How do chameleons differ from other lizards in their walking gait?

They keep their vertebral column nearly straight and place their feet directly beneath the body in the parasagittal plane.

What are zygodactylous toes?

A specialized toe arrangement found in chameleons that aids in grasping objects while climbing.

How does wet adhesion function in amphibians?

Specialized toe pads with polygonal epithelial cells secrete mucus, and the viscosity of this mucus contributes to the adhesive force.

What are scansors in gecko toe pads?

Pads with transversely expanded, platelike scales called lamellae located beneath the toe tips.

What are setae and spatulae in the context of gecko adhesion?

Setae are the microscopic hairs on scansors, and spatulae are the even smaller, terminal structures that maximize surface contact.

Under what conditions do gecko setae lose their adhesive force?

When the setal angle exceeds 30 degrees to the substrate, which happens as the toes curl up from the surface.

What is the difference between parachuting and gliding?

Parachuting involves falling at an angle steeper than 45 degrees, while gliding involves falling at an angle flatter than 45 degrees.

How does the lizard Draco support its patagia for gliding?

The patagia are supported by five to seven elongate ribs that are spread by muscular action.

How does the paradise tree snake (Chrysopelea paradisi) glide?

It flattens its body into a broadly rounded, ventrally concave triangular shape while undulating through the air.

What is the primary function of the metatarsal tubercle in burrowing amphibians?

It is used to dig by extending the legs alternately and turning the foot upward to expose the tubercle against the substrate.

Why do some arboreal frogs have extensive webbing between their digits?

The webbing acts as a surface area expansion to facilitate parachuting or gliding during aerial movement.

What is the role of the iliocostalis muscle in Draco lizards?

It pulls the first two ribs forward, which triggers the spreading of the entire airfoil supported by the remaining ribs.

How does body size affect adhesion in frogs?

Larger species have larger individual cells and lower channel density, which disproportionately increases the area of surface contact.

What are the two primary types of aquatic suction feeding mechanisms?

Compensatory suction and inertial suction.

Which groups of animals utilize inertial suction feeding?

Aquatic salamanders (larvae and paedomorphic adults), larval caecilians, aquatic frogs, tadpoles, and some turtles.

What are the three main cartilages involved in the buccal and pharyngeal regions of tadpoles?

Palatoquadrate, ceratohyal, and branchial basket.

What is the function of labial teeth (denticles) in tadpoles?

They are used for feeding and are adapted to the specific diet and habitat of the tadpole.

What is the primary difference in mouth-opening mechanics between crocodylians and other reptiles?

Crocodylians open their mouths by lifting their head, rather than lowering their jaw.

What is the function of the trochlear process in turtle feeding?

It acts as a pulley to change the direction of the pull of the adductor mandibulae muscles.

How do Pleurodire and Cryptodire turtles differ in the formation of the trochlear process?

In Pleurodires, it is formed by the pterygoid bone; in Cryptodires, it is formed by the quadrate and/or prootic bones.

Which muscles are responsible for closing the mouth in crocodylians?

The adductor mandibulae and two massive pairs of pterygoideus muscles.

In salamander projectile feeding, what is the function of the subarcualis rectus muscle?

It acts as the tongue extensor.

In salamander projectile feeding, what is the function of the rectus cervicis muscle?

It acts as the tongue retractor.

What is 'inertial elongation' in the context of frog feeding?

A mechanism where the tongue is extended rapidly using momentum and muscle action to capture prey.

What are the key muscles involved in frog tongue projection?

Genioglossus, hyoglossus, and submentalis.

How do chameleons achieve tongue projection?

Movement of the ceratohyal cartilage moves the entoglossal process, powered by the accelerator and hyoglossal muscles.

What are four key skull adaptations in Alethinophidia snakes that allow them to swallow prey larger than their head?

Elongated quadrate bone, no mandibular symphysis, intramandibular joint, and a moveable maxilla.

What is a prokinetic skull in snakes?

A skull with a hinge that allows for increased mobility and gape during prey ingestion.

What is the physiological effect of constriction on a prey item?

It typically causes circulatory arrest and prevents the prey from breathing.

What are the three main groups of snakes categorized by envenomation adaptations?

Colubrids, Elapids, and Viperids.

What is the role of the retroarticular process in caecilian feeding?

It serves as a lever arm for the muscles (like the depressor mandibulae) that open the jaw.

What is the function of the ventral velum in tadpoles?

It acts as a valve to prevent the backflow of water during suspension feeding.

What is the primary feeding adaptation of Scolecophidia snakes?

Skull adaptations specifically designed for feeding on small prey like ants.

What is the function of the adductor mandibulae in terrestrial feeding?

It is the primary muscle responsible for closing the jaw.

What are the three primary dietary categories for amphibians and reptiles?

Herbivory, carnivory, and omnivory.

How does suction feeding generate the necessary force to capture prey?

It relies on generating negative pressure by rapidly expanding the volume of the buccopharyngeal cavity.

What is compensatory suction in aquatic feeding?

An increase in buccopharyngeal cavity volume that compensates for the forward movement of the head, preventing the predator's attack from creating a pressure wave that pushes prey away.

What is inertial suction in aquatic feeding?

A mechanism where the expansion of the neck accommodates displaced water, creating an inward flow that pulls prey into the mouth.

What role do denticles play in tadpole feeding?

They anchor the tadpole's mouth to a substrate while the upper and lower beaks scrape algae.

How do tadpoles increase buccal volume to facilitate suction feeding?

The paired orbitohyal muscles lift the lateral tips of the ceratohyals, dropping the floor of the mouth.

What constraint do burrowing adaptations place on caecilian feeding?

Skull modifications for burrowing limit the size of the adductor mandibulae muscles.

What is the function of the retroarticular process on the mandible in caecilians?

It provides the interhyoid muscle with a long in-lever, allowing for powerful closing of the jaws.

What are the two primary muscles responsible for closing the mouth in crocodylians?

The adductor mandibulae and the pterygoideus.

Which muscle is responsible for opening the mouth in crocodylians?

The depressor mandibulae.

How do chameleons determine prey distance?

They use accommodation (focusing) with a single eye rather than relying on binocularity.

Where is elastic energy stored during projectile tongue feeding in frogs?

The energy is stored directly within the muscle fibers themselves.

Where is elastic energy stored during projectile tongue feeding in salamanders and chameleons?

It is stored in sheets of connective tissue that are deformed by the contraction of the tongue-powering muscle.

What is cranial kinesis?

A condition where parts of the skull move relative to other parts, widespread among squamates.