Biology 1012 Life: The Natural World Week 6, Chapter 5 Notes
Biology 1012 Life: The Natural World Week 6, Chapter 5 Notes Biol 1012
Popular in Life: The Natural World
verified elite notetaker
Popular in Biology
verified elite notetaker
This 3 page Class Notes was uploaded by Madison Lovegren on Saturday October 1, 2016. The Class Notes belongs to Biol 1012 at University of Northern Iowa taught by Barton L Bergquist in Fall 2016. Since its upload, it has received 11 views. For similar materials see Life: The Natural World in Biology at University of Northern Iowa.
Reviews for Biology 1012 Life: The Natural World Week 6, Chapter 5 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 10/01/16
Chapter 5 The Terrestrial Environment 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 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) 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 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 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 5.7 The Soil Body Has Horizontal Layers of Horizon 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) 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 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