Zoology- Birds/Amphibians/Reptiles

Describe the parts of the amniotic eggs and their purposes.

Shell: Water-tight protective covering that allows for retention of water and nutrients.

Albumin: Provides the embryo with water, protein, and acts as a cushion.

Chorion: Membrane surrounding the embryo, yolk sac, and allantois. Functions in gas exchange between the embryo and the external environment.

Amnion: Fluid filled cavity providing an internal aquatic environment.

Yolk Sac: Provides nutrients to the embryo.

Allantois: Stores nitrogen waste produced by the embryo and facilitates respiration.

Why is the amniotic egg an important adaptation?

The evolution of the extraembryonic membranes led to less dependence on water for development and allowed amniotes to branch out into drier environments. The shell provides protection for the developing embryo while still being permeable enough to allow for the exchange of carbon dioxide and oxygen.

Why/how did the Testudines evolve to have anapsid skulls?

Turtles were originally classified as anapsid (no temporal fenestrae). More recent molecular and fossil evidence shows that turtles arose with the diapsid (two temporal fenestrae) line and secondarily lost the two temporal fenestrae, thus they only appear to be anapsid but are classified as diapsid.

Describe the metamorphosis of the order Anura.

1. Mating occurs in water, often in vegetation. Females secrets a gelatinous mass and lays the eggs in the mass, where the male then releases sperm over them.

2. Eggs develop into tadpoles. Tadpoles are herbivores, have gill buds, a lateral line, and a long finned tail.

3. Tadpole undergoes complete metamorphosis into an adult frog:

Develops lungs, leg buds, external ear drums, and a carnivorous digestive system. Gills and lateral line disappear at the same time. Hind legs develop before front legs. Tail is slowly reabsorbed.

Describe the Amphibian Circulatory System.

3-Chambered heart; Double Circuit

1. Enter right atrium: Deoxygenated blood

2. Enter left atrium: Oxygenated blood

3. Both atriums empty into the ventricle. Some blood mixing occurs.

4. Ventricle sends deoxygenated blood to the respiratory organs and oxygenated blood out to the body.

Describe the Reptile Circulatory System.

3-Chambered heart; Double Circuit

1. Enter right atrium: Deoxygenated blood

2. Right atrium blood goes to the ventricle, then back out the the lungs to be oxygenated.

3. Enter left atrium: Oxygenated blood

4. Left atrium blood goes to the ventricle, which sends mostly oxygenated blood to the aorta and out to the body.

5. Little mixing of blood occurs in the ventricle due to the partial septum and pressure differences.

*Crocodiles and Alligators have a 4-chambered heart.

Describe the Avian Circulatory System.

4-chambered heart; two atria and two ventricles.

1. Oxygenated blood and Deoxygenated blood are kept separate.

2. Enter right atrium: Deoxygenated blood

3. Right atrium sends blood to the right ventricle, which is then sent to the lungs to be oxygenated.

4. Enter left atrium: Oxygenated blood from lungs.

5. Left atrium sends blood to the left ventricle, which is then sent to the aorta and out to the body.

Describe Countercurrent Respiration in birds.

Inhale 1: Air travels to the posterior air sac.

Exhale 1: Air travels from posterior air sac to the lungs.

Inhale 2: Air travels from the lungs to the anterior air sac. At the same time, new air travels to the posterior air sac.

Exhale 2: Air in the anterior air sac leaves the body, and air in the posterior air sac enters the lungs.

Describe the temperature dependent sex determination in reptiles.

Crocodilia:

Cooler- Female

Warmer- Male

86-91 F- Mix of sexes

Sphenodontia:

Cooler- Female

Warmer- Male

70 F- Equal chance M/F

Testudines:

Cooler- Male

Warmer- Female

82-89 F- Equal chance M/F

Squamata:

Sex is determined by sex chromosomes.

Match the Order to the correct common name of its members.

Urodela ("tail"): Salamanders, Axolotls, etc.

Anura ("without tail"): Frogs and Toads

Apoda ("no legs"): Caecilians

Crocodilia: Alligators, Crocodiles, Caiman, and Gharials.

Sphenodontia: Tuataras

Squamata: Lizards and Snakes

Testudines: Turtles, Tortoises, and Terrapins

List the benefits of flight.

1. The ability to flee predators.

2. The ability to catch flying prey such as flying insects or smaller birds.

3. Nesting off the ground to provide more safety from predation.

List and describe the adaptations that allow flight in birds.

1. One ovary

2. No urinary bladder

3. Countercurrent respiration: always fresh oxygenated air in the respiratory system while flying.

4. Homethermic: They maintain a constant elevated body temperature to support the metabolism for flight.

5. Feathers: Feather arrangement forms wings into airfoils.

6. Pneumatic bones: very light bones to reduce weight while flying.

7. Skeleton: All vertebrate except the neck are fused to create support while flying.

8. Muscles: Main leg muscles are in the thigh instead of lower legs to maintain a close center of gravity and improve cold resistance.

9. Enlarged nervous and sensory system organs to control balance and other aspects of flight.

Describe the differences between lizards and snakes.

Lizards: Four limbs

Snakes: No limbs

Lizards: Moveable eyelids, External ears.

Snakes: No moveable eyelids, no external ears.

Lizards: Straight teeth position

Snakes: Teeth are curved backwards

Lizards: Most have excellent vision

Snakes: Most have poor vision

Lizards: Use tongue to catch and eat prey.

Snakes: Use construction or venom to kill and eat prey.