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UNI / Biology / BIOL 1012 / What is the meaning of water balance in biology?

What is the meaning of water balance in biology?

What is the meaning of water balance in biology?


School: University of Northern Iowa
Department: Biology
Course: Life: The Natural World
Professor: Barton bergquist
Term: Fall 2016
Tags: Biology, terrestrial, and Environment
Cost: 25
Name: Biology 1012 Life: The Natural World Week 6, Chapter 5 Notes
Description: All the main points of Chapter 5 in the textbook
Uploaded: 10/02/2016
3 Pages 13 Views 3 Unlocks

Chapter 5 ­ The Terrestrial Environment

What is the meaning of water balance in biology?

5.1 ­ Life on Land Imposes Unique Constraints

Desiccation ­ when something that usually contains moisture is dried out completely ∙ This has been the biggest constraint imposed by terrestrial living environments Water Balance ­ when organisms must contain a balance of water between themselves and  their surrounding environment 

∙ Certain plants have evolved different cells to prevent water loss as they have adapted to  terrestrial life

The need to remain erect in a terrestrial environment has resulted in strong evolution of  structural materials

∙ Giant kelp can stay standing in water due to the gas­filled bladders in each blade of the  plant, but when taken out of water, they cannot support their own weight

What is the meaning of the leaf area index (lai)?

∙ However, a tree that is normally in a terrestrial environment can remain standing on its  own

Variations in temperature and precipitation are also part of a terrestrial environment ∙ These have a short term effect on metabolic processes and a long term effect on the  evolution and distribution of terrestrial life (plant and animal)

∙ Results in distinct patterns of terrestrial ecosystems

5.2 ­ Plant Cover Influences the Vertical Distribution of Light

∙ The amount of light that gets through a canopy and reach the ground varies with both  the quantity and location of the leaves

∙ As you move from the top of the canopy to the bottom, light decreases because of the  cumulation of leaves and the Leaf Area Index (LAI)

What is the meaning of regolith in soil?

Leaf Area Index (LAI) ­ the area of leaves per unit of ground area

∙ The amount of light reaching the ground varies with the seasons

∙ Only about 1­5% of light reaches the ground If you want to learn more check out What are the procedures of research?

∙ Sunflecks on the forest floor enable plants to endure shaded conditions

5.3 ­ Soil is the Foundation Upon Which All Terrestrial Life Depends ∙ Soil is the medium for all plant growth

∙ Also the main factor controlling fate of water in terrestrial environments ∙ Nature’s recycling system (waste products are broken down)

∙ Habitat for small mammals all the way to microbial life

Soil is difficult to define, but one known thing is that it is a living system full of small animals,  fungi, and bacteria

Regolith ­ unconsolidated layer of debris over the hard, unweathered rock ∙ Soil is formed at this interface between rock and air

5.4 ­ The Formation of Soil Begins with Weathering

∙ Formation of soil begins with weathering of rocks and their minerals

∙ Mechanical weathering (also called physical weathering) ­ when water, wind and  temperature break down rock

∙ Chemical weathering ­ the activity of soil organisms the acids they produce, and  rainwater break down primary minerals

5.5 ­ Soil Formation Involves 5 Interrelated Factors

Five interdependent factors:

1. Parent material

2. Climate We also discuss several other topics like What does periphery mean?

3. Biotic factors ­ plants, animals, bacteria, and fungi

4. Topography ­ influences the amount of water that enters the soil and rates of erosion 5. Time ­ required for full development of distinctive soils

Parent material ­ material form which soil develops

∙ Physical characteristics and chemical composition of the parent material play an  important role in determination of soil properties, especially during the early stages Leaching ­ movement of solutes through the soil

5.6 ­ Soils Have Certain Distinguishing Characteristics

Soil differs in the physical properties of texture, color, and depth

∙ Color has little direct effect on how a soil functions, but it can be used to relate chemical  and physical properties

∙ Soil texture is the proportion of different sized soil particles ­ silt, sand, and clay ∙ Texture is largely determined by parent material, also influenced by soil forming process ∙ Soil depth varies across landscape, depending on slope, weathering, vegetation, and  parent material We also discuss several other topics like What is the importance of the central dogma?

5.7 ­ The Soil Body Has Horizontal Layers of Horizon Don't forget about the age old question of Does the economy of the united states affect world markets?

∙ Soil develops in horizons (layers)

∙ Four horizons are commonly recognized, but that doesn’t mean that they are all present  in every type of soil

∙ O ­ organic layer (or horizon)

∙ A horizon (topsoil) We also discuss several other topics like What is yale's approach to an attitude change?

o Characterized by accumulation of organic matter

∙ B horizon (subsoil) in which mineral materials accumulate

∙ C horizon ­ unconsolidated material under the subsoil

5.8 ­ Moisture­Holding Capacity Is an Essential Feature of Soils

Saturated ­ when water exceeds what the pore space in the soil can hold Field capacity ­ when water fills all the pore spaces and is held there by capillary forces Capillary water ­ water held between soil particles by capillary forces

Wilting Point ­ when moisture levels decrease to a point at which plants can no longer extract  water

Available Water Capacity ­ amount of water retained by the soil between field capacity and  wilting point

5.9 ­ Ion Exchange Capacity Is Important to Soil Fertility

∙ Soil particles, especially clay particles and organic matter, are important to nutrient  availability and cation exchange capacity of soil ­ the number negatively charged sites  on soil particles that can attract positively charged ions If you want to learn more check out Who wrote the age of reason according to the wealth of nations?

∙ Cations are in a state of equilibrium

5.10 ­ Soil Formation Processes Form Different Soils

5 main soil forming processes:

1. Laterization ­ humid environments, tropical, subtropical regions

2. Podzolization ­ cool, moist climates

3. Calcification ­ evaporation and water uptake by plants exceed precipitation 4. Salinization ­ similar to calcification, but in much drier climates

5. Gleization ­ areas with high rainfall and poor water drainage

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