Gas Exchange

Question 1

Ventilation

Answer 1

A mechanical process that moves gas into and out of the body
Passive and active

Question 2

Respiration

Answer 2

Biological process occurring in all cells in the body where food and oxygen are taken in to release energy for the cell

Question 3

Water as a respiratory medium

Answer 3

Kroghs diffusion coefficient
air = 11 seawater = 0.000034
As a resp. medium water paws greater phys. challenges than air
Oxygen solubility reduces as salinity increases

Question 4

Water density

Answer 4

800x denser than air
Viscosity 35x higher at 40 degrees and 100x at 0 degrees

Question 5

Importance of light and oxygen

Answer 5

Earliest life were heterotrophs required autotrophs
linked by photosynthesis and respiration

Question 6

Gas exchange - 2 mechanisms

Answer 6

Diffusion - across membrane
Convection - brings inspired gas to peripheral regions and removes waste

Question 7

Gas exchange - structures

Answer 7

Internal = usually actively ventilated
External = relies on water movement

Question 8

Ventilation processes

Answer 8

Unidirectional- different entrance and exit
Tidal (in-out)
Non directional (unpredictable)

Question 9

Bimodal breather

Answer 9

Can breath air or water

Question 10

Gas exchange - diffusion

Answer 10

O2 and CO2 move across epithelium - transport into tissue
From high partial pressure to low partial pressure

Question 11

Echinoderms - gas exchange

Answer 11

Sea stars perform gas exchange across epithelium of branchial papulae and tube feet
Complex respiratory trees in holothurians

Question 12

Polychaete - gas exchange

Answer 12

Distributed gills along body wall
Forced over gills by ciliary beating
Tentacles function as gills

Question 13

Molluscs - gas exchange

Answer 13

Diverse respiratory system
Mantle overhangs which contains internal gills
Ciliary action generates current around gills
These gills also serve secondary function as feeding organs

Question 14

Crustaceans

Answer 14

-Branchial chambers ventilated by specialised appendage that drives water through an opening
-Negative pressure is created within branchial chamber drawing water in

Question 15

Merostomata

Answer 15

Pairs of hinge plate book gills

Question 16

Fish

Answer 16

Gills - counter current flow

Question 17

Sharks

Answer 17

Well developed spiracles that allow water to be drawn into the buccal cavity over gills (active ventilation)

Question 18

bi modal respiration

Answer 18

-Obtain oxygen from two different sources: water (via gills) and air (via specialized respiratory structures such as lungs or other air-breathing organs)
-Cope with hypoxic conditions – particularly where warm water temperatures significantly reduce the amount of dissolved O2

Question 19

Gas exchange: Speeding up diffusion

Answer 19

*Pump blood through the gills
*Pump water across the gills (ventilation)
*Increase gill surface area – have thin gill epithelium (gill cover)
*Optimizing convection – concurrent (same direction of bloodflow) vs countercurrent gas exchange

Question 20

Respiration versus Metabolism

Answer 20

-Respiration includes the transport of oxygen into the body/cells and transport of carbon dioxide out of the body
-Metabolism includes the cellular processes by which energy is obtained such as through the breakdown of glucose (includes cellular respiration).

Question 21

Aerobic metabolism

Answer 21

requires oxygen
-efficient = 38 atp from 1 glucose
- carried out by eukaryotes in the mitochondria via kreb cycle

Question 22

Anaerobic respiration

Answer 22

doesnt require oxygen
inefficient but faster = only 2 atp
performed by eukaryotes and pro.
completed in the cytoplasm by glycolysis

Question 23

Steady state locomotion

Answer 23

• “Cruising”/”Routine” behavior: Fueled aerobically, primarily using red muscle fibers
• Can be sustained for long periods of time

Question 24

Unsteady state locomotion

Answer 24

• Sudden, intense exertion (“burst”): Fueled anaerobically, primarily utilizing white muscle fibers
• Causes lactate accumulation
• Can lead to fatigue

Question 25

Energy savings during locomotion: Flying birds

Answer 25

• Social behavior also provides energy savings to locomotion.
• E.g., birds are flying in a v-formation.

Question 26

Energy savings during locomotion: Schooling fish

Answer 26

• Fish can use the same principles to save energy when swimming schools, with following fish taking advantage of the eddies produced by leading this.
• Fish take advantage of eddies produced by leading fish
• In the striped surfperch, we see this effect both in terms of pectoral fin beat frequency and in terms of oxygen consumption, with both traits lower in following or trailing fish.

Question 27

metabolism

Answer 27

-a useful characteristic to measure as it can tell us a lot of information about an animal´s ambient state, in particular helping us to understand what factors increase or decrease the energetic demand of an individual, influencing how much food it needs.
-the rate at which an animal consumes energy and is measured in units of calories per unit time or watts

Question 28

what is metabolic rate referred to as

Answer 28

metabolic rate is sometimes referred to aa the rate of heat production

Question 29

standard metabolic rate

Answer 29

an ectotherm´s minimal maintenance costs and is an integrated measure of an animal´s physiological energy expenditures

Question 30

basal metabolic rate

Answer 30

An endothermic animal that thermoregulates, like birds or humans
the amount of energy (calories) that an organism needs to maintain basic bodily functions while at rest.

Question 31

routine metabolic rate

Answer 31

includes both minimum maintenance costs and the energetic needs to maintain routine activity.

Question 32

Maximum metabolic rate

Answer 32

represents an animal´s maximum aerobic metabolic limits

Question 33

Aerobic scope

Answer 33

Difference between an organism’s resting metabolic rate (RMR) or basal metabolic rate (BMR) and its maximum aerobic metabolic rate (MAMR)

Question 34

Factors that influence metabolic rate

Answer 34

intensity of physical activity and the temperature of the environment
gender, food, age, circadian rhythms, body size, reproduction, hormones, and more

Question 35

Specific Dynamic Action

Answer 35

Increase in metabolic rate caused by food ingestion

Question 36

Body size

Answer 36

• Larger animals in general have high absolute metabolic rate than smaller animals
• However, this increase in metabolic rate is slower than linear (1:1)

Question 37

Hypoxia

Answer 37

• Episodes of low dissolved oxygen following natural (e.g., rock pool) or anthropogenic (e.g., eutrophication follow runoff of pollutants from land) factors
• Oxygen solubility declines at warmer temperatures, so hypoxic events exaserbated by climate change

Question 38

3 strategies to cope with hypoxia

Answer 38

-Enhance oxygen uptake, transport, and delivery
-Rely more heavily on anaerobic metabolism
-Depress their metabolic needs for lower reliance on aerobic metabolism

Question 39

Methods to measure metabolic rate

Answer 39

Indirect calorimetry - Most accurate but technically and logistically difficult
Direct Calorimetry - by burning the materials under pure oxygen conditions, and measuring the heat released
– Respirometry - Measures an animal´s rate of respiratory gas exchange, particularly oxygen consumption, as a proxy for aerobic metabolism

Question 40

Field metabolic rate

Answer 40

Metabolic rate measured in a free-roaming animal and holistic measurement of metabolic rate in a particular ecological context
- biologgers and otoliths microchemistry