Zoology Exam 4 Flashcards
Most distinctive turtles
Meiolaniidae
Most terrestrial turtles
tortoises
Name of turtle’s upper shell
carapace
Name of turtle’s lower shell
plastron
Function of plastron
allow the front and rear lobes to be pulled upward to close the openings of the shell
The extant turtles
Cryptodires
Pleurodires
Retract their head into their shell by bending the neck in a vertical S shape
cryptodires
Retract their heads by bending the neck horizontally
Pleurodires
Marine turtles are _________
cryptodires
Characteristics of Turtles
• Turtle shell composed of upper carapace and lower plastron.
• All turtles lay eggs.
• No turtle exhibits parental care of offspring.
• Turtles have specialization for terrestrial, freshwater, and
marine environments.
• Most turtles are long-lived with poor capacity for rapid
population growth.
• For some species, sex of offspring is determined by
temperature.
Currently accepted hypothesis about skull of turtles
diapsid origin
Characteristics of carapace
• Epidermal and bone origins.
Characteristics of plastron
Dermal ossifications.
Entoplastron and epiplastra
Characteristics of turtle shell
• Hinges may be present in shell.
• Kinetic shell.
• Occurrence of hinges may be sexually dimorphic.
• Kinetic shell evolved independently multiple times.
• Ribs external to girdles.
• Extant turtles have 8 cervical vertebrae and 10 trunk
vertebrae.
• Articulations of cervical vertebrae permit bending of neck.
Chracterstics of Shell and Skeleton of Cryptodires
- Ginglymes permit vertical rotation
* Have two sacral vertebrae
Chracterstics of Shell and Skeleton of Pleurodires
• Use ball-and-socket or cylindrical joints between cervical
vertebrae.
• Have pelvic girdle fused to the carapace with a less distinct
sacral region.
Characteristics of Turtle heart.
• Has ability to shift blood between pulmonary and systemic
circuits.
• Accomplished by having two continuous ventricular
chambers.
• Three subcompartments: cavum pulmonale, cavum
venosum, and cavum anteriosum.
Characteristics of Turtle respiration.
Large, dorsal lungs.
Changes in pressure
• Thus, both inhalation and exhalation require muscular
activity.
• In and out movements of forelimbs and soft tissue of shell
conspicuous during respiration.
• Respiration without need for ribs may have contributed to
evolution of shell.
In the respiration of Turtles, changes in pressure are a result of?
• Changes in pressure result of:
• Contracting muscles that move visceral organs upward,
compression lungs.
• Contracting muscles increase volume of visceral cavity
causing visceral organs to lower.
The characteristics of of lungs of turtles
• Attached to carapace dorsally and laterally.
• Ventrally, lungs attached to non-muscular connective tissue
of the visceral organs.
•Weight of visceral organs pull on connective tissue.
What are the patterns of Circulation and Respiration
Turtles exhibit right-to-left intracardiac shunt
•When resistance is the same in both pulmonary and system
circuit, deoxygenated blood may bypass lungs and flow into
systemic circuit.
• Function of shunt may be to match lung ventilation with
pulmonary gas flow.
• Shunt may stabilize oxygen concentration in blood.
• Shunt may reduce blood flow during breath holding to
permit more effective use of oxygen stored in lungs.
What is the relationship between thermoregulation and body suze?
Large Body Size
• Contributes to thermal inertia.
• Slows rate of heating and cooling.
• At small body sizes, temperature regulation more difficult.
• Because of their large size, many marine turtles obtain some
degree of endothermy.
• Evidence of counter-current exchange mechanism in
flippers.
Often used by turtles in social encounters.
Mechanosensory, visual, and chemosensory signals
primarily used by males
against males and sometimes females.
Mechanosensory stimulation
Courtship of tortoises
- Some tortoises have glands that enlarge during breeding
season and produce pheromones. - Head movements may function as social signal in some
tortoises. - Vocalization
Describe the Nesting behavior of turtles
- All turtles are oviparous.
- Female turtles use hind limbs to dig nest in sand or soil and deposit eggs
- Some eggs deposited in late summer or fall and exhibit
diapause during winter. - Resume development when temperatures increase in spring.
Environmental Effects on Egg Development
- Temperature, moisture, and gas concentrations can influence
turtle development. - Temperature can determine sex of embryo.
Temperature can determine sex of embryo in what way?
- Higher temperatures usually result in females.
2. Lower temperatures usually result in males.
Used by turtles navigating between feeding and breeding habitats
Visual landmarks, sun orientation, chemical cues,
mechanosensory cues, and magnetism
Navigation and Migration in Marine Turtles
• Most carnivorous.
• Males remain offshore for courtship and mating.
• Females come ashore to deposit eggs.
• Evidence for light, wave direction, and magnetism in
navigation.
Describe conservation of turtles.
- Many species produce few offspring.
- Habitat loss, especially for nesting can be catastrophic.
- Increasing occurrence of turtle diseases.
Characteristics of Lepidosaurs
• Integument covered with scales impermeable to water.
• Outer layer of epidermis shed periodically.
• Most have four appendages, but many have secondarily lost
appendages.
• Characterized by transverse cloaca and intervertebral
breakage zones.
Sister group to lizards and snakes
Tuatara
Derived from lizards
snakes
Characteristics of Tuatara
- Adult tuatara reach length of 60 cm.
- Both males and females territorial.
- Tuatara nocturnal with low body temperatures.
- Jaws and teeth produce shearing effect.
Major lineages of squamates
- Iguania
* Scleroglossa
characteristics of lizards
• Range in size from 3 cm to 3 m.
• 80% of lizards weigh less than 20 g.
• Most large lizards are herbivores.
• Most constrained by conflict between locomotion and
respiration.
• Limb reduction or loss has evolved independently more
than 60 times.
• Leglessness usually associated with life in dense grass or shrubbery where slim, elongate body can better
maneuver.
Characteristics of Amphisbaenians digging lizards (fossorial).
• Rigid skulls used for tunneling.
• Single median tooth in upper jaw
• Nippers can remove small pieces of tissue.
• Integument characterized by annuli (rings).
• Not connected to trunk.
• Forms tube that body capable of sliding forward or
backward inside.
• Some species have blunt heads.
• Others have vertically or horizontally keeled snouts.
Ancestral condition of snakes represented by?
Scoecophidia