Biology of Animals - Quiz 3

Cutaneous respiration

diffusion through the membrane - a process where gas exchange occurs through the skin. Pros: minimal energy. Cons: you have to be small and simple

Tracheal system (arthropod system)

Series of branching tubes

Can be ventilated with movement

Direct transport to cell

Independent of a circulatory system

First step!

Countercurrent flow

a mechanism where two fluids (liquids or gases) move in opposite directions across a boundary to maximize the transfer of heat or a substance, like oxygen

CONCEPT: Selection differs in aquatic versus terrestrial systems

Selection differs between aquatic and terrestrial systems due to the contrasting physical and chemical environments, which shape traits like feeding, attachment, and life history strategies

CONCEPT: Smaller organisms can acquire oxygen via simpler, more direct mechanisms

Smaller organisms can effectively respire via passive diffusion or cutaneous

CONCEPT: Countercurrent flow maximizes gas exchange

Countercurrent flow maximizes gas exchange by having fluids move in opposite directions, which maintains a constant concentration gradient that allows for more efficient transfer of a substance like oxygen from water to blood in fish gills.

CONCEPT: Mammals have a highly inefficient respiratory system

Air exits where enters; bidirectional

Dead air in passageways where gas exchange does not occur

Passive gas exchange between capillaries and alveoli, active in the diaphragm

CONCEPT: Birds have an efficient, unidirectional system adapted for flight

Air enters through the trachea directly into air sac - then to the lungs, then again to the second air sac, then exits the body

2 cycles of inhalation/exhalation

CONCEPT: Efficiency in the respiratory system is related to metabolic rate

The body needs to supply cells with the oxygen required for metabolic processes like cellular respiration. A higher metabolic rate requires more oxygen, which in turn necessitates a more efficient respiratory system to meet the demand

Gastrovascular cavity

Central digestive/circulatory compartment in simple animals

One opening

Diffusion

Small, aquatic animals

Open circulatory system

Lacks blood vessels, capillaries

Has hemolymph (fluid) and hemocoel (blood sinus)

Water, proteins, salts, phagocytic cells

20-40% volume!

Simplest in terrestrial organisms

BATHED IN BLOOD

Single closed circulatory system

Distinct blood vessels, capillaries

Hydrostatic pressure - what differentiates closed vs open circulatory systems - blood can move fast! More efficient

Failsafe valves

5-10% volume!

Heart = pumps one time in circuit

Sinus venosus - holding chamber before atrium

Blood pressure highest before ventricle

Conus or Bulbous arteriosus = holding chamber after ventricle

Slow and low metabolism and blood pressure

Double closed circulatory system

Distinct blood vessels, capillaries

Hydrostatic pressure - what differentiates closed vs open circulatory systems - blood can move fast! More efficient

Failsafe valves

5-10% volume!

Differential pumping pressure

Larger body size

Pulmonary circuit - low pressure

Systemic circuit - high pressure

Importance: endothermy, terrestrial ecology, body size

Diastole

relaxation (chambers fill)

Systole

contraction (blood pumped)

Main anatomy of mammal heart

Left atrium (oxygenated)

Left ventricle (oxygenated)

Tricuspid valve

Right atrium (deoxygenated)

Right ventricle (deoxygenated)

Bicuspid valve

Aorta

Hemoglobin

Oxygen transportation

All kingdoms (common), not all organisms

Vertebrates

Binds 4 oxygen

Confined to RBCs

Terrestrial environments

Red

Hemocyanin

Oxygen transportation

2nd most common

Cephalopods (Mollusca) & Crustaceans (Arthropoda)

Hemolymph

2 copper (Cu) binds to 1 oxygen

Free-floating protein, high densities

Cold, low oxygen environments

Efficacy decreases with acidification

Colorless to blue

CONCEPT: Circulation is important for transporting gas, nutrients, and waste

Circulation delivers oxygen from the lungs and nutrients from the digestive system to all cells, while also removing waste products like carbon dioxide, which is then taken to the lungs to be exhaled.

CONCEPT: Cellular respiration in larger animals requires respiratory pigments, with oxygen saturation variable throughout the circulatory system

Larger animals require respiratory pigments like hemoglobin to transport enough oxygen for cellular respiration

CONCEPT: Differences in the efficiency of the pump systems in closed v. open systems are tightly correlated with metabolism & ecology

Open system - small, simple organisms

Closed system - single pump = slower metabolism, double pump = larger bodies and higher metabolism

CONCEPT: Respiratory pigments (hemoglobin & hemocyanin) facilitate gas exchange & also are correlated with ecology

Respiratory pigments like hemoglobin and hemocyanin facilitate gas exchange by dramatically increasing the blood's oxygen-carrying capacity beyond what can be dissolved in plasma alone. Their structure and function are strongly correlated with an animal's ecology, adapting to environmental factors like oxygen availability, metabolic needs, and habitat type.

CONCEPT: Metabolic rate is associated with body size and endothermy

For endotherms (warm-blooded animals), smaller animals have a higher metabolic rate per unit of mass compared to larger animals. This is because their larger surface-area-to-volume ratio leads to faster heat loss, requiring a higher metabolic rate to maintain a stable internal temperature. Additionally, endothermy as a whole results in a much higher metabolic rate than that of an ectotherm (cold-blooded) of the same size, because endotherms must expend energy to generate their own body heat.

CONCEPT: More specialized circulatory systems are important for the evolution of endothermy, terrestrial ecology, and larger body sizes

Specialized circulatory systems were crucial for the evolution of endothermy, terrestrial ecology, and larger body sizes because they enabled the efficient transport of oxygen and nutrients necessary to meet higher metabolic demands and overcome the limitations of simple diffusion over greater distances - and 4 chambers with specialization means no deoxygenated blood left circulating around body.

External respiration

Occurs as a function of partial pressure differences in oxygen and carbon dioxide between the alveoli and the blood in the pulmonary capillary

Internal respiration

Occurs as a function of partial pressure differences in oxygen and carbon dioxide between tissue and the blood in the capillary, which are opposite of those present at the respiratory membrane