20 Questions
What is the primary function of water in the body in terms of heat transfer?
Water helps to absorb and transfer heat from areas where it is generated to areas that need more heat or can dissipate excess heat.
What is specific heat capacity, and what is the value for water?
Specific heat capacity is the heat required to raise the temperature of 1g of a material by 1°C (or K). The specific heat capacity of water is 4.18Jg−1K−1.
Why does water have a high specific heat capacity?
Water has a high specific heat capacity because hydrogen bonds restrict molecular motion, requiring a large amount of energy to break these bonds and raise its temperature.
How does the specific heat capacity of water affect aquatic habitats?
The high specific heat capacity of water helps to maintain a stable temperature in aquatic habitats, making them more thermally stable than terrestrial habitats.
What is the main difference in energy expenditure between the ringed seal and the Arctic loon?
The ringed seal expends more energy to move through water due to its higher viscosity, while the Arctic loon expends more energy to stay aloft in air due to its lower density.
Why does the ringed seal have an easier time maintaining its body temperature than the Arctic loon?
The seal has an easier time maintaining its body temperature because water has a higher thermal conductivity, allowing it to dissipate excess heat more efficiently.
How does the viscosity of water affect the movement of organisms in aquatic habitats?
The higher viscosity of water creates more drag on a body moving through it, requiring more energy to move at the same velocity as in air.
What is the effect of water's thermal conductivity on submerged animals?
Water's high thermal conductivity conducts heat away from the bodies of submerged animals.
Why is it easier for the Arctic loon to maintain a temperature above that of the environment?
It is easier for the loon to maintain a temperature above that of the environment because air acts as an insulator, reducing heat loss.
What is the overall effect of water's physical properties on organisms living in aquatic habitats?
Water's physical properties, such as its high specific heat capacity and thermal conductivity, provide a more stable thermal environment for organisms living in aquatic habitats.
What is the role of water's high specific heat capacity in the human body?
To maintain a stable body temperature
Why is the specific heat capacity of water higher than that of air?
Because hydrogen bonds restrict molecular motion
What is the consequence of water's high specific heat capacity on aquatic habitats?
The habitats are more thermally stable
How does the density of water affect the energy expenditure of the ringed seal?
It increases the energy needed for movement
What is the effect of water's thermal conductivity on the ringed seal's body temperature?
It conducts heat away from the body
Why is the ringed seal better adapted to its aquatic habitat than the Arctic loon?
Because the seal's body temperature is more stable in water
What is the effect of air's low thermal conductivity on the Arctic loon's body temperature?
It insulates the body from the environment
How does the viscosity of water affect the movement of the ringed seal?
It increases the drag on the seal's body
What is the main difference in the habitats of the ringed seal and the Arctic loon?
The seal lives in water, the loon in air
What is the general consequence of the physical properties of water on organisms living in aquatic habitats?
They are positively affected by the high specific heat capacity
Study Notes
The Origins of Life
- The first organisms likely emerged in warm water, not a pond, and most hypotheses place the first cells in the oceans.
- The formation of the first cells involved a small volume of water becoming enclosed in a membrane, allowing chemical reactions to occur between solutes.
Properties of Water
- Water molecules (H2O) have covalent bonds between oxygen and hydrogen atoms, making them polar due to unequal sharing of electrons.
- This polarity gives water molecules a partial positive charge (hydrogen atoms) and a partial negative charge (oxygen atom), allowing them to attract and repel each other.
Hydrogen Bonds
- Hydrogen bonds are a type of intermolecular force that forms between two water molecules, with a slightly positive hydrogen atom in one molecule attracted to a slightly negative oxygen atom in another.
- Hydrogen bonds are weak, but due to the large number of water molecules, they have significant effects.
- Hydrogen bonds are responsible for water's unique properties, such as cohesion and surface tension.
Cohesion and Surface Tension
- Cohesion is the attraction between water molecules, which allows them to stick together.
- Surface tension is the property of water that causes it to behave as if it has an "elastic skin" at its surface.
- This is due to the attraction between water molecules and the air particles above them, causing them to minimize their surface area.
Adhesion and Capillary Action
- Adhesion is the attraction between water molecules and other substances, such as glass or cellulose.
- Capillary action is the movement of water through narrow tubes or spaces, driven by the release of energy as hydrogen bonds form between water and the tube material.
Solvent Properties
- Water is a polar solvent, allowing it to dissolve a wide variety of substances, including charged and polar molecules.
- Water's solvent properties are essential for metabolic processes and transport in living organisms.
Metabolism and Transport
- Cytoplasm is an aqueous solution, where water serves as a medium for metabolic reactions and the movement of solutes.
- In transport systems, water acts as a solvent for the transport of substances, such as minerals and sugars, in plants and animals.
Physical Properties of Water
- Buoyancy: The upward force exerted on an object by a fluid, which affects the density of living organisms and their ability to float or sink.
- Viscosity: The stickiness of a fluid, which affects how easily it can flow.
- Thermal conductivity: The rate at which heat passes through a material, which is high in water and affects the ability of aquatic organisms to maintain body temperature.
- Specific heat capacity: The heat required to raise the temperature of a material, which is high in water due to the energy required to break hydrogen bonds.
Importance of Water's Physical Properties
- Buoyancy affects the energy requirements for movement in different habitats.
- Viscosity affects the energy required for movement in water.
- Thermal conductivity and specific heat capacity affect the ability of organisms to maintain body temperature and resist changes in temperature.
The Origins of Life
- The first organisms likely emerged in warm water, not a pond, and most hypotheses place the first cells in the oceans.
- The formation of the first cells involved a small volume of water becoming enclosed in a membrane, allowing chemical reactions to occur between solutes.
Properties of Water
- Water molecules (H2O) have covalent bonds between oxygen and hydrogen atoms, making them polar due to unequal sharing of electrons.
- This polarity gives water molecules a partial positive charge (hydrogen atoms) and a partial negative charge (oxygen atom), allowing them to attract and repel each other.
Hydrogen Bonds
- Hydrogen bonds are a type of intermolecular force that forms between two water molecules, with a slightly positive hydrogen atom in one molecule attracted to a slightly negative oxygen atom in another.
- Hydrogen bonds are weak, but due to the large number of water molecules, they have significant effects.
- Hydrogen bonds are responsible for water's unique properties, such as cohesion and surface tension.
Cohesion and Surface Tension
- Cohesion is the attraction between water molecules, which allows them to stick together.
- Surface tension is the property of water that causes it to behave as if it has an "elastic skin" at its surface.
- This is due to the attraction between water molecules and the air particles above them, causing them to minimize their surface area.
Adhesion and Capillary Action
- Adhesion is the attraction between water molecules and other substances, such as glass or cellulose.
- Capillary action is the movement of water through narrow tubes or spaces, driven by the release of energy as hydrogen bonds form between water and the tube material.
Solvent Properties
- Water is a polar solvent, allowing it to dissolve a wide variety of substances, including charged and polar molecules.
- Water's solvent properties are essential for metabolic processes and transport in living organisms.
Metabolism and Transport
- Cytoplasm is an aqueous solution, where water serves as a medium for metabolic reactions and the movement of solutes.
- In transport systems, water acts as a solvent for the transport of substances, such as minerals and sugars, in plants and animals.
Physical Properties of Water
- Buoyancy: The upward force exerted on an object by a fluid, which affects the density of living organisms and their ability to float or sink.
- Viscosity: The stickiness of a fluid, which affects how easily it can flow.
- Thermal conductivity: The rate at which heat passes through a material, which is high in water and affects the ability of aquatic organisms to maintain body temperature.
- Specific heat capacity: The heat required to raise the temperature of a material, which is high in water due to the energy required to break hydrogen bonds.
Importance of Water's Physical Properties
- Buoyancy affects the energy requirements for movement in different habitats.
- Viscosity affects the energy required for movement in water.
- Thermal conductivity and specific heat capacity affect the ability of organisms to maintain body temperature and resist changes in temperature.
Explore the formation of the first cells and the evolution of life on Earth, from Charles Darwin's 'warm little pond' to modern hypotheses about the origins of life in the oceans.
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