Ch. 2
Properties of water: water stays liquid over a broad range of temperatures and resists changes between its solid, liquid, and gaseous states. Because water is dense it provides support for organisms, but water is also viscous meaning that it resists the flow or movement of a body through it.
Many inorganic nutrients are dissolved in water; water dissolves various substances making them accessible to living systems and providing a medium within which they can react to form new compounds. The powerful solvent properties of water are responsible for the presence of minerals in streams, rivers, lakes and oceans.
Lower the pH= more acidic; higher the pH= more basic; 7 is neutral, includes most streams and rivers
Soils consist of particles of clay, silt and sand as well as particles of organic material, in varying proportions. Soils with abundant clay and silt hold more water than coarse sands, through which water drains quickly. However because clay particles are small and hold water tightly, less water is available to plants in a clay soil than in a soil with a mixture of particles of different sizes, commonly called a loam.
As soils dry out the remaining water is held ever more tightly because a greater proportion of that water lies close to the surfaces of soil particles.
Plants acquire the inorganic nutrients they need—other than oxygen, carbon, and some nitrogen—as ions dissolved in water in the soil around their roots. Nitrogen exists in soil as ammonium (NH4 1) and nitrate ions (NO3 2), phosphorus as phosphate ions (PO4 32), calcium and potassium as their elemental ions Ca21 and K1, respectively.
Plants can reduce water loss by closing their stomates; closing of the stomates prevents further water from escaping, but it also prevents the carbon dioxide required for photosynthesis from entering the leaf. (Trade off)
Terrestrial animals reduce their use of water for eliminating excess salts by concentrating salts in their urine or by excreting them through salt glands.
Hyperosmotic organisms: tend to gain water from their surroundings and lose solutes; hypo-osmotic organisms they tend to lose water to the surrounding seawater and must replace it by drinking seawater, the incoming salt is excreted by gills and kidneys.
The soil horizons consist of: O (organic layer) A (topsoil) B (subsoil) C (weathering rock) & R (bedrock aka parent rock)
The strength of the attractive forces holding water in the soil is called the water potential of the soil, this is mostly generated by the attraction of water to the surfaces of soil particles.
Leaves themselves generate water potential when water evaporates from leaf cell surfaces into the air spaces within the leaves, a process known as transpiration.
The column of water in a xylem element is continuous from the roots to the leaves, because it is held together by hydrogen bonds between the water molecules. So low water potentials can draw water upward though the xylem elements in against the osmotic potential of the living root cells and the pull of gravity. Transpiration creates a continuous gradient of water potential from leaf surfaces in contact with atmosphere to the surfaces of root hairs in contact with the soil water. This explanation of the mechanism of water movement from roots to leaves is known as the cohesion- tension theory.
Gas exchange between the atmosphere and the interior of the leaf occurs through small openings at the leaf surfaces, called stomates (Figure 2.12). (Many botanists prefer the term stomata, singular stoma, from the Latin for “mouth.”) The stomates are the points of entry for CO2 and the exits for water escaping to the atmosphere by transpiration.
Many mangroves maintain high concentrations of organic solutes—various amino acids and small sugar molecules—in their roots and leaves to increase their osmotic potential. In addition, salt glands in the leaves secrete salt by active transport to the exterior leaf surface. Many mangrove species also exclude salts from their roots by active transport. Because many of these adaptations parallel those of plants from environments with scarce water, the mangrove habitat can be thought of as an osmotic desert, even though plant roots are frequently immersed in water.
Osmoconformers: (i.e. Marine invertebrates) isotonic they conform to their environment
Osmoregulators: (i.e. Ray-finned fish) regulate their inside content
Animals & Nitrogen: Most carnivores, whether they eat crustaceans, fish, insects, or mammals, consume excess nitrogen. This nitrogen is part of the proteins and nucleic acids in their diet, and it must be eliminated from the body when these compounds are metabolized. Most aquatic animals produce a simple metabolic by-product of nitrogen metabolism: ammonia (NH3). Although ammonia is mildly poisonous to tissues, aquatic animals eliminate it rapidly in copious dilute urine, or directly across the body surface, before it reaches a dangerous concentration within the body.
*****SPECIAL THANKS TO K.A. :)
Properties of water: water stays liquid over a broad range of temperatures and resists changes between its solid, liquid, and gaseous states. Because water is dense it provides support for organisms, but water is also viscous meaning that it resists the flow or movement of a body through it.
Many inorganic nutrients are dissolved in water; water dissolves various substances making them accessible to living systems and providing a medium within which they can react to form new compounds. The powerful solvent properties of water are responsible for the presence of minerals in streams, rivers, lakes and oceans.
Lower the pH= more acidic; higher the pH= more basic; 7 is neutral, includes most streams and rivers
Soils consist of particles of clay, silt and sand as well as particles of organic material, in varying proportions. Soils with abundant clay and silt hold more water than coarse sands, through which water drains quickly. However because clay particles are small and hold water tightly, less water is available to plants in a clay soil than in a soil with a mixture of particles of different sizes, commonly called a loam.
As soils dry out the remaining water is held ever more tightly because a greater proportion of that water lies close to the surfaces of soil particles.
Plants acquire the inorganic nutrients they need—other than oxygen, carbon, and some nitrogen—as ions dissolved in water in the soil around their roots. Nitrogen exists in soil as ammonium (NH4 1) and nitrate ions (NO3 2), phosphorus as phosphate ions (PO4 32), calcium and potassium as their elemental ions Ca21 and K1, respectively.
Plants can reduce water loss by closing their stomates; closing of the stomates prevents further water from escaping, but it also prevents the carbon dioxide required for photosynthesis from entering the leaf. (Trade off)
Terrestrial animals reduce their use of water for eliminating excess salts by concentrating salts in their urine or by excreting them through salt glands.
Hyperosmotic organisms: tend to gain water from their surroundings and lose solutes; hypo-osmotic organisms they tend to lose water to the surrounding seawater and must replace it by drinking seawater, the incoming salt is excreted by gills and kidneys.
The soil horizons consist of: O (organic layer) A (topsoil) B (subsoil) C (weathering rock) & R (bedrock aka parent rock)
The strength of the attractive forces holding water in the soil is called the water potential of the soil, this is mostly generated by the attraction of water to the surfaces of soil particles.
Leaves themselves generate water potential when water evaporates from leaf cell surfaces into the air spaces within the leaves, a process known as transpiration.
The column of water in a xylem element is continuous from the roots to the leaves, because it is held together by hydrogen bonds between the water molecules. So low water potentials can draw water upward though the xylem elements in against the osmotic potential of the living root cells and the pull of gravity. Transpiration creates a continuous gradient of water potential from leaf surfaces in contact with atmosphere to the surfaces of root hairs in contact with the soil water. This explanation of the mechanism of water movement from roots to leaves is known as the cohesion- tension theory.
Gas exchange between the atmosphere and the interior of the leaf occurs through small openings at the leaf surfaces, called stomates (Figure 2.12). (Many botanists prefer the term stomata, singular stoma, from the Latin for “mouth.”) The stomates are the points of entry for CO2 and the exits for water escaping to the atmosphere by transpiration.
Many mangroves maintain high concentrations of organic solutes—various amino acids and small sugar molecules—in their roots and leaves to increase their osmotic potential. In addition, salt glands in the leaves secrete salt by active transport to the exterior leaf surface. Many mangrove species also exclude salts from their roots by active transport. Because many of these adaptations parallel those of plants from environments with scarce water, the mangrove habitat can be thought of as an osmotic desert, even though plant roots are frequently immersed in water.
Osmoconformers: (i.e. Marine invertebrates) isotonic they conform to their environment
Osmoregulators: (i.e. Ray-finned fish) regulate their inside content
Animals & Nitrogen: Most carnivores, whether they eat crustaceans, fish, insects, or mammals, consume excess nitrogen. This nitrogen is part of the proteins and nucleic acids in their diet, and it must be eliminated from the body when these compounds are metabolized. Most aquatic animals produce a simple metabolic by-product of nitrogen metabolism: ammonia (NH3). Although ammonia is mildly poisonous to tissues, aquatic animals eliminate it rapidly in copious dilute urine, or directly across the body surface, before it reaches a dangerous concentration within the body.
*****SPECIAL THANKS TO K.A. :)