Lab 4 Flashcards
Generalized tetrapod locomotion
Fore and hind limbs roughly equal in length and relatively small compared to the body size
Limbs splayed outward from the body
Zygopophyses of the vertebral column are small providing some support
Body only slightly elevated off the ground during movement
Advantages of snake locomotion
The ability to move through dense vegetation or in tight spaces
Movement is relatively quiet when compared to limbed lizards
Serpentine movements works well in water much like anguilliform swimming
Locomotion of snakes
Complete loss of pectoral pelvic girdles and limbs
Dramatic elongation of the thoracic region of the vertebral column
Loss of sternum- ribs only attached to vertebrae
Ribs elongate and in contact with ground
Specialized ventral scales called scutes
5 types of snake locomotion
Serpentine
Rectilinear
Concertina
Sidewinding
Lass locomotion
Serpentine
Like anguilliform swimming
Move in a s-shaped curve
Simplest and fastest form of locomotion
Used by snakes that swim too
Rectilinear
Allows the snake to move forward when lateral undulations are restricted
Using bands of muscles that attach the scutes to the ribs, the snake inches each scute forward and presses it down on the substrate while lifting up and advancing the next scute
The pattern is repeated to slowly advance
Concertina
Employed in tight spaces where some lateral movement is available
The posterior part of the body forms curves that press laterally, anchoring the snake against the wall while the anterior end extends forward.
The anterior end then does this step and this cycle is repeated
Sidewinding
Employed by snakes that need to move over very sandy and loose soils
Snake’s body is raised off of substrate, leaving only two or three points of contact
Loops of the body held off the ground move forward along successive points of contact creating a distinct track way of separate depressions in the sand
Also maintains temp with limited contact on the ground
Lass locomotion
Snake creates a lass-like loop around trees or poles
Snake grips the structure and moves its body upward
Energetically expensive
Frog features for locomotion
Hind limb greatly enlarged while fore limb is smaller or reduced
Shortened vertebral column with not ribs
Loss of tail
Pelvic girdle elongate robust
Fusion of several caudal vertebrae into Urostyle
Feeding adaptations
Eyes placed high on head
Pedicellate teeth
Muscular tongue
No secondary palate
Tadpoles
Eyes placed high on head
Many amphibians are ambush predators who obscure their bodies under the water’s surface
Eyes placed on the top of the head allow them to watch for prey above the water
Pedicellate teeth
Unique to lissamphibians
Small teeth functioned to grip
Muscular tongue
Most anurans (frogs/toads)
Some urodeles (salamanders)
Extend the tongue during prey capture
No secondary palate
Allows specialized muscles to draw the eyes downward into oral cavity
Many anurans use their eyes to aid in swallowing
Tadpoles
Most larval amphibians are herbivorous
Adult amphibians are carnivorous
Anapsids
No openings in the skull
Synapsids
One opening in the skull
Diapsids
2 openings in the skull
Turtle feeding structures
Anapsid skull
Keratinized beaks
Muscular tongue
Anapsid skull turtle
Because turtles and tortoises feed on soft foods that are swallowed whole
As a result a stronger bite force isn’t required
Keratinized beaks turtles and tortoises
Turtles lack teeth but use a sharp beak to slice or crush their food
Many turtles have keratinized structures such as plates for crushing or sharp tooth-like spines to prevent escape
Muscular tongue (turtles and tortoises)
Non-protrusible tongue and is used to transport food into the esophagus
Lizard feeding adaptations
Diapsid skull
Cranial kinesis
Well developed teeth
Protrusible tongues
Jacobsen’s organ
Diapsid skull lizards
The two temporal fenestrae allow for greater muscles attachment and connection related expansion
Provides increased bite-force
Loss of the lower temporal bar allows for greater flexibility in the skull
Cranial kinesis lizards
Independent movement of parts of the cranium
Larger mouth opening but may also act in absorbing impact forces created by rapid jaw closure or struggling prey
Well developed teeth lizards
Continually replaced
Pointed and slightly curves
Protrusible tongues lizards
May be used for prey capture or olfaction
Jacobsen’s organ
Pocket of nasal sensory tissue
Shared with many mammals
Picks up scent molecules from the environment and delivers them directly to the Jacobsen’s organ
Snake feeding adaptations
Diapsid skull highly modified
Extreme cranial kinesis
Constriction
Venom
Diapsid skull highly modified snakes
Loss of the upper and lower temporal bars is associated with increased mobility of the snake cranium
Extreme cranial kinesis snakes
Snake skulls are extremely flexible and capable of complex movements associated with swallowing large prey whole
Lack of contact between left and right halves of lower jaw
One negative of this is snake skulls are fragile
Constriction snakes
Suffocating prey to make consuming easier
Venom snakes
Deliver toxins to incapacitate prey and then swallow whole
Crocodilian feeding features
Diapsid skull
Eyes dorsal
Strongly socketed teeth
Rostrum shape
Secondary palate
Diapsid skull crocs
Two temporal fenestrae make robust jaw closing strong
Strongly socketed teeth
Replace teeth continuously
Teeth are deeply and firmly socketed
Sharp conical teeth
Rostrum shape
The shape of the snout is highly correlated to the type of prey they feed on
Broad snouted crocs prey on relatively large vertebrates and the shape of their rostrums may maximize gape size and structural strength
Narrow snouted crocs eat fish and allow for more rapid movement and jaw closure under water
Secondary palate crocs
Allows them to continue breathing while keeping their mouth open under water but also protects the brain and sensory structures of the head from damage due to large, struggling or hard-bodied prey in the mouth
Advantages of auditory communication
amphibians
Sound passes around objects and vegetation
Can provide greater specificity and complexity than chemical communication
Can be precisely timed
Effective at night or in dark environments
Can travel over long distances
Disadvantages of auditory communication
amphibians
Sound may alert predators
Calls can be energetically expensive
Cryptic coloration types
amphibians
Camouflage
Countershading
Camouflage
Pigmentation that matches well with their environment
Countershading
amphibians
Like many aquatic and semi-aquatic vertebrates, amphibians often display a dark dorsal surface and lighter ventral surface
Aposematic coloration
amphibians
Highly poisonous frogs are brightly colored to warn off predators
Mimicry
amphibians
Adaptations of colors and patterns to make an individual appear to be of different species in order to deceive predators
Threat mimicry
Mimics another animal that poses a threat to the predator
Aposematic mimicry
The individual mimics the coloration of a toxic species
Integumentary adaptations in amphibians
Highly glandular skin
Estivation
Pelvic patches
Vascularized skin folds
Epidermal claws
Highly glandular skin
Skin is rich in poison and mucous glands
There are two types of poison glands
Two poison glands
Dorsolateral ridges
Parotoid glands
Dorsolateral ridges
Many frogs bear conspicuous paired ridges running from near the eyes to posterior tip of the body
Parotoid glands
Typical of toads, parotoid glands lie just behind the head on either side of the body
Estivation
Some species retain successive molts of the outer layer of skin and form a temporary cocoon during periods of dormancy
Pelvic patches
Zones of increased surface area where the skin rests on the moist substrate
Increases uptake of moisture
Vascularized skin folds
Conspicuous folds of excess skin increasing surface are for respiration
Epidermal claws
Keratinized epidermal claws present in some species
Integumentary adaptations in reptiles
Scales
Spines
Rattle
Scutes
Bony plates
Claws
Beaks
Scales
Epidermal structures composed mostly of keratin
Spines
Protection against predators
Rattle
Used to warn off predators
Scutes
Modified for locomotion
Bony plates
Dermal bone is sometimes produced in conjunction with scales to increase their protective capacity
Two types of bony plates
Osteoderms
Carapace/Plastron
Osteoderms
Lie underneath scales are produced by dermis
Carapace/plastron
The carapace (upper shell) and plastron (lower shell) are complex structures composed of endochondral bone, dermal bone and scales
Claws
Made up of the upper Unguis and lower Subunguis
Beaks
Turtles and tortoises use in place of teeth
