Reptiles

Question 1

How many openings does the reptilian skull have and why?

Answer 1

Two; openings (fenestration) provide additional surface for muscle attachment (Diapsid) giving more power to the jaw for hunting prey.

Question 2

What are Chelonians and what is unique about their skull?

Answer 2

Turtles; have lost their skull fenestration and have now an anapsid skull.

Question 3

What features of reptilian skin limits water loss?

Answer 3

Dry/scaly, permanent stratum corneum (moulting), beta-keratin makes skin more rigid.

Question 4

What features of the amniotic egg meant it was evolutionarily successful ?

Answer 4

Calcium-impregnated shell prevents evaporation of fluids inside but allows gas exchanges, large quantities of yolk allows embryo to attain a relatively advanced state of development before it hatches (no metamorphosis).

Question 5

What kind of teeth do reptiles have?

Answer 5

Turtles have a horny beak, all other reptiles have them teeth on both the palate and the jaws, most have homodont dentition however partial heterodoxy occurs in snakes (i.e. fangs).

Question 6

How did orientation of limbs change from amphibians to reptiles?

Answer 6

In amphibians, orientation is outward from main axis, however in reptiles the appendages are rotated towards the body meaning the limbs are more parallel to main axis.

Question 7

Why is parallel limb orientation important for reptiles?

Answer 7

Provides better support for the weight of the body and makes greater agility and speed possible.

Question 8

Give an overview of reproduction in reptiles?

Answer 8

Internal fertilisation, males have a copulatory organ, females can store sperm for months, most species are oviparous.

Question 9

What do viviparous reptiles exhibit?

Answer 9

A placentae formed by the appositions of maternal and embryonic tissues.

Question 10

What are the sexual chromosomes most reptiles?

Answer 10

XY Male /XX Female

Question 11

What is the less likely sexual chromosomes of reptiles i.e. Komodo dragons?

Answer 11

WZ Female /WW Male

Question 12

What term is given to sex determination in reptiles?

Answer 12

Temperature dependant sex determination

Question 13

What sex does high incubation temperatures cause in turtles?

Answer 13

Females

Question 14

How can the Viviparous lizard select the sex of her embryos?

Answer 14

Can influence gestation temperature by basking behaviour.

Question 15

What is Parthenogenesis?

Answer 15

Complete absence of male contributions; no sexual reproduction

Question 16

What species exhibit parthenogenesis?

Answer 16

Whiptail lizards, geckos and blind snakes.

Question 17

How do reptilian lung differ from that of amphibians?

Answer 17

More developed; divided into chambers and sub-chambers (faveoli) which increase the surface area for gas exchange.

Question 18

What is unique of turtle respiration?

Answer 18

Some gas exchange takes place inside the mouth, in the cloaca and across the leathery skin that covers the shell.

Question 19

What term is given to the type of breathing reptiles use?

Answer 19

Negative pressure breathing.

Question 20

Describe how most reptiles breathe?

Answer 20

They have no diaphragm, but expand and compress the body cavity by movements of the ribs produced by contracting the intercostal muscles.

Question 21

How come some lizards can only run for 1-2 minutes?

Answer 21

Lateral movements to the left compress the left lung and vice versa. Air is pumped between lungs but little in/out through the trachea.

Question 22

Why do snakes have a single dominant left lung?

Answer 22

The anterior part is non-respiratory and instead functions as an air sac, glutei help respiration when ingesting large prey.

Question 23

Describe the key features of lungs in turtles?

Answer 23

Lie within protected ridged shell, fixed rib cage cannot act to ventilate lungs, they have specialised sheets of muscle within the shell that contract and relax the lungs, air pressure in lungs can be changed by moving limbs in and out.

Question 24

What type of air flow do alligators exhibit?

Answer 24

Unidirectional.

Question 25

What differs with the heart of crocodilians?

Answer 25

The separation of the ventricles in complete (4 chambered heart) and an incomplete septum which reduces mixing of blood.

Question 26

What kind of vision do reptiles that are active during the day use?

Answer 26

Reptiles that are active during the day have complex eyes (rods and oil droplets) that can see colour well.

Question 27

What kind of vision do reptiles that are active at night use?

Answer 27

Lizards have large pupillary and lens aperture, and snakes use infrared vision.

Question 28

What organ do some snakes have for infrared vision?

Answer 28

Pit organ.

Question 29

What does the vomeronasal organ do?

Answer 29

Located on the palate to detect chemicals via the tongue.

Question 30

How can you tell how much the vomeronasal organ is used?

Answer 30

Degree of the fork of the tongue.

Question 31

How does the pit organ in snakes work?

Answer 31

Detection of infrared radiation > transient receptor potential channels > activates thermosensors in the vertebrate nervous system .

Question 32

What structure detects airborne vibrations in reptiles?

Answer 32

External visible tympanic membrane.

Question 33

What structure detects ground vibrations in reptiles?

Answer 33

The quadrate which forms part of the jaw joint.

Question 34

What term is given to reptiles’ thermoregulation?

Answer 34

Ectotherms

Question 35

What belongs to Squamata?

Answer 35

Lizards and snakes

Question 36

How can snakes be distinguished from legless lizards?

Answer 36

Lack of eyelids, external ears and ear opening.

Question 37

What family contains most of the snake species?

Answer 37

Colubroidea.