LT Animal

Question 1

fish: number of ventricle, atria, circuits, blood mixing?

Answer 1

1 ventricle, 1 atrium, 1 ciruit, no blood mixing

Question 2

amphibians: number of ventricle, atria, circuits, blood mixing?

Answer 2

1 ventricle, 2 atria, 2 circuits, blood mixing

Question 3

reptiles (except crocodilians): number of ventricle, atria, circuits, blood mixing?

Answer 3

1 ventricle, 2 atria, 2 circuits, blood mixing (& partial septum)

Question 4

birds and mammals: number of ventricle, atria, circuits, blood mixing?

Answer 4

2 ventricles, 2 atria, 2 circuits, no blood mixing (complete septum)

Question 5

What are vertebrates?

Answer 5

Animals with heads and spinal cords protected by a backbone.

Question 6

What is a closed circulatory system?

Answer 6

Blood pumped through vessels in a unidirectional flow (heart → arteries → capillaries → veins → heart).
Valves prevent backflow.

Question 7

What is an open circulatory system?

Answer 7

Hemolymph pumped into a cavity where it surrounds cells before returning to the heart.
(not always enclosed in vessels)

Question 8

Functions of the respiratory system?

Answer 8

Oxygen diffusion into the blood.
Carbon dioxide diffusion out of blood into the air.

Question 9

Characteristics of respiratory systems?

Answer 9

Extensive capillary networks.
Large, thin surface area.
Must remain moist for gas exchange.

Question 10

Respiratory structures in tetrapods vs. aquatic organisms?

Answer 10

Gills in water.
Lungs in terrestrial environments.
Amphibians: Use lungs, mouth lining, and skin for respiration.

Question 11

What are systemic and respiratory capillary beds?

Answer 11

Systemic: Oxygen delivered to cells.
Respiratory: CO₂ removed from blood and expelled.

Question 12

Fish circulatory and respiratory systems?

Answer 12

Respiration:
Gills specialized for water.
Breathing: Water enters mouth → forced through gill slits → oxygen diffuses across filaments.
Circulation:
Single loop.
Low blood pressure (muscle movement aids return flow).

Question 13

Amphibians’ respiratory system?

Answer 13

Simple lungs.
Mouth lining for gas exchange (at rest on land).
Skin for underwater respiration.

Question 14

Amphibians’ circulatory system?

Answer 14

3 chambers: 1 ventricle, 2 atria.
2 loops: Pulmocutaneous and systemic circuits.
Blood mixing reduced by:
Ventricular ridge.
Timed contractions.

Question 15

Reptiles’ respiratory system?

Answer 15

Lungs with alveoli for efficient gas exchange

Question 16

Reptiles’ circulatory system?

Answer 16

Non-crocodilian:
3 chambers.
2 circuits.
Partial septum reduces blood mixing.
Crocodilian:
4 chambers.
2 circuits.
Blood mixing via foramen of Panizza (hole between two aortae).
Aortae:
Main: Carries oxygenated blood.
Bypass: Active during apnea (carries deoxygenated blood).

Question 17

Birds and mammals’ respiratory system?

Answer 17

Highly branched lungs with alveoli for gas exchange.
Efficient for oxygen uptake (endotherms, high activity levels).

Question 18

Birds and mammals’ circulatory system?

Answer 18

4 chambers: Fully separate systemic and pulmonary circuits.
No blood mixing (convergent evolution).

Question 19

What did all tetrapods evolve from

Answer 19

fish-like ancestors

Question 20

What are characteristics of animals with high metabolic demands?

Answer 20

Extensive use of muscles for activities like flying (birds) or running (mammals).
Endothermy: Internal mechanisms to regulate body temperature.
Require efficient respiratory and circulatory systems to supply oxygen and remove CO₂.

Question 21

Why do birds and mammals have high metabolic needs?

Answer 21

Endothermy demands a continuous supply of energy to maintain body temperature.
High muscle activity levels (e.g., flying or running) require rapid oxygen delivery.

Question 22

What adaptations support high metabolism in birds and mammals?

Answer 22

Highly efficient lungs with extensive branching and alveoli for gas exchange.

Question 23

What are characteristics of animals with low metabolic demands?

Answer 23

Ectothermy: Dependence on the environment for temperature regulation.
Lower muscle activity (e.g., “sit-and-wait” predators like reptiles).
Tissues require less oxygen, and CO₂ buildup is slower.

Question 24

Why do reptiles have low metabolic needs?

Answer 24

They are ectotherms and don’t expend energy on temperature regulation.
They engage in less frequent, intense physical activity compared to endotherms.