The Terrestrial Environment Flashcards
It greatly increases the constraint imposed by gravitational forces?
Dessication (constraint)
It results from the displacement of water that helps organisms in aquatic environments overcome the constraints imposed by gravity?
The upward force of buoyancy
What do you call the tendency of an object to float in a fluid?
Buoyancy
What are the structural materials that is needed in terrestrial environments to remain erect against gravitational force?
- skeletons (for animals)
- cellulose (for plants)
Example that imposes the unique constraint against the life on land
Macrocystis pyrifera (kelp)
What is a Macrocystis pyrifera?
A giant kelp inhabiting the waters off the coast in California
- It grows in dense stands called kelp forests
- Anchored to the bottom sediments
- can grow 100 feet or more toward the surface
Macroalgae (kelp) or Seaweed
How does the kelp kept afloat?
They have gas-filled bladders attached to each blade
When the kelp plants are removed from the water, what will happen?
they collapse into a mass
Why would the kelp collapse into a mass when it is removed from the water?
Lacking supportive tissues strengthened by cellulose and lignin
Light passing through a canopy of vegetation becomes ____
Attenuated (reduce)
What influeces the amount of light that passes through reaching the ground?
- density
- orientation of leaves in a canopy
Foliage density is expressed as
LAI
LAI
Leaf Area Index
Leaf Area Index (LAI)
the area of leaves per unit of ground area
The amount of light reaching the ground in terrestrial vegetation ___ with the ____
varies with the season
In forest, how many percent of light striking the canopy reaches the ground?
1- 5 percent
_____ on the forest floor enable plants to endure ____ ____
- Sunflecks
- shaded conditions
Sunflecks
a specific area that has small amount of light that can pass through
Formula to get the LAI
LAI = total leaf area/projected ground area
- a natural product formed and synthesized by the weathering of rocks and the action of living organisms.
- a collection of natural bodies of earth, composed of mineral and organic matter and capable of supporting plant growth.
Soil
It is a breaking of rocks into small particles (formation of soil)
Weathering
Types of Rocks
- Igneous
- Sedementary
- Metamorphic
- a pioneer of modern soil studies
- one eminent soil scientist that will not give an exact definition of soil
Hans Jenny
Soil is a ___ ___ of ______ ____ and ____ ___ on Earth’s surface.
- natural product
- unconsolidated mineral and organic matter
Why is the Soil a foundation for all terrestrial life?
- it is the medium for plant growth
- a principal factor controlling the fate of water
- nature’s recycling system (breaks down waste products and transforms into their basic elements)
- a habitat to a diversity of animal life
Where does soil formation begin?
Begins with the weathering of rocks and minerals
Water, wind, temperature and plants break down rocks
Mechanical weathering
- the activity of soil organisms, the acids they produce, and rainwater break down primary minerals
- it alters the chemical composition of rocks
Chemical weathering
Mechanical weathering results from the ____ of ___ ___
Interaction of several forces
Rock surfaces flake and peel away, when?
when exposed to the combined action of water, wind, and temperature
How does Water work to form rock into soil?
Water seeps into crevices, freezes, expands, and cracks the rock into smaller pieces
Wind-borne particles, such as __ and __, wearaway at the __ ____.
- dust and sand
- rock surface
Growing ___ of trees ___ rock apart.
- roots
- splits
Five Interrelated Factors Involve in Soil Formation
- Parent material
- Climate
- Biotic factors
- Topography
- Time
- it provides the substrate from which soil develops
- where soil came from
- what rock it started
Parent material
Where could the original parent material originate?
- underlying bedrock
- glacial deposits (till)
- sand and silt carried by the wind (eolian)
- gravity moving material down a slope (colluvium)
- sediments carried by flowing water (fluvial) including water in floodplains
glacial deposits
till
sand and silt carried by the wind
eolian
gravity moving material down a slope
colluvium
sediments carried by flowing water, including water in floodplains
fluvial
It shapes soil development through temperature, precipitation, and its influence on vegetation and animal life
Climate
How does Climate shapes soil development?
Through temperature, precipitation, and its influence on vegetation and animal life
The vegetation, animals, bacteria, and fungi—add organic matter and mix it with mineral matter
Biotic Factors
- influences the amount of water entering the soil and the rates of erosion
- the contour of the land, can affect how climate influences the weathering process.
Topography
It can affect how climate influence the weathering process
The contour of the land
- it is a crucial element in soil formation
- forming well-developed soils may require 2000 to 20,000 years.
Time
How many years will it take to form a well-developed soils?
2000 to 20,000 years
Soils differ in the ___ ___ of __, ___, and ___
- physical properties
- color, texture, and depth
- indicates what element is present in the soil
- has a little direct influence on soil function
- indicates the chemical composition of the rocks and minerals form which the soil was formed
Color
an organic matter that makes soil dark or black
Humus
What is color of the soil if oxides of iron is present?
Yellowish-brown to red
What is color of the soil if manganese oxides is present?
Purplish to black
What is color of the soil if Quartz, kaolin, gypsum, and carbonates of calcium and magnesium is present?
Whitish and grayish
What color indicates poorly drained soils or soils saturated by water?
Blotches of various shades of yellowish-brown and gray
- proportion of different-sized soil particles
- largely determined by the parent material but is also influenced by the soil-forming process
Texture
It consists of particles larger than 2.0 mm, but they are not part of the fine fraction of soil
Gravel
It ranges from 0.05 to 2.0 mm, is easy to see, and feels gritty
Sand
It consists of particles from 0.002 to 0.05 mm in diameter that can scarcely be seen by the naked eye
Silt
It is a particles are less than 0.002 mm and are too small to be seen under an ordinary microscope
Clay
It varies across the landscape, depending on slope, weathering, parent materials, and vegetation
Depth
In the pyramid chart:
Sand
Arrow-up-left [ \ ]
In the pyramid chart:
Silt
Arrow-down-left [ / ]
In the pyramid chart:
Clay
Horizontal Arrow from Left or Right
It is soils develop in layers
Horizons
What are the four Horizons commonly recognized
- O horizon or Organic Layer
- A (sometimes E) or Topsoil
- B or Subsoil
- C horizon
Layer of Soil:
It is dominated by the organic material, consisting of undecomposed or partially decomposed plant materials, such as dead leaves
O horizon or Organic Layer
Layer of Soil:
Characterized by accumulation of organic matter
A (sometimes E) horizon or Topsoil
Layer of Soil:
In which mineral materials accumulate
B horizon or Subsoil
Layer of Soil:
The unconsolidated material underlying the subsoil and extending downward to the bedrock
C horizon
What would you discover if you dig into the surface layer of a soil after a soaking rain?
a sharp transition between wet surface soil and the dry soil below
As rain falls on the surface, it moves into the soil by ____
Infiltration
Water moves by ___ into the open ___ ___ in the soil
- gravity
- pore spaces
What determines the amount of water that can flow in?
the size of the soil particles and their spacing
It increases the rate of water infiltration
Wide pore spacing at the soil surface
In wide pores spacing at the soil surface ___ __ have a ___ ____ __ than ___ __ do.
- coarse soils
- higher infiltration rate
- fine soils
An essential feature of soils
Moisture-Holding Capacity
What is one of the important characteristics of soil?
The amount of water a soil can hold
When there is more water than pore space can hold, the soil is ___
Saturated
If water fills all the pore spaces and is held there by internal capillary forces, the soil is at ___ ____
Field capacity
When the moisture level is at a point where plants cannot extract water, the soil has reached ___ ___
Wilting point
The amount of water retained between field capacity and wilting point is the ____ ___ ____
Available Water Capacity
The available water capacity of a soil is a _____ of its ____
Function of its texture
What is important to soil Fertility?
Ion Exchange Capacity
Chemicals within the soil ____ into the soil water to form a ___
- dissolve
- solution
What do you call the chemicals that is dissolved into the soil water that forms into a solution?
Exchangeable nutrients
these ____ ____ in solution are the most ___ ___ for ___ and __ by plants
- chemical nutrients
- readily available
- uptake and use
They are held in soil by the ____ ____ of oppositely charged particles and are ___ ____ with the soil solution
- simple attraction
- constantly interchanging
A charged particle
Ion
What are Ions that carries a positive charge?
Cations
What are Ions that carries a negative charge?
Anions
What chemical elements and compounds exist in the soil solution as cations?
- Calcium (Ca2+)
- Magnesium (Mg2+), and
- Ammonium (NH4+)
What chemical elements and compounds exist in the soil solution as anions?
- Nitrate (NO3−) and
- Sulfate (SO4 2−)
The ability of these ions in soil solution to bind to the surface of soil particles depends on what?
The number of negatively or positively charged sites within the soil
What are important to nutrient availability and the cation exhange capacity of the soil?
soil particles,particularly clay particles and organic matter
What is the cation exchange capacity of the soil?
the number of negatively charged sites on soil particles that can attract positively charged ions
Cations occupying the negatively charged particles in the soil are in a state of ___ ___ with similar cations in the soil solution.
dynamic equilibrium
What is the percentage of sites occupied by ions other than hydrogen?
Percent base saturation
What is the broadest level of soil classification?
Order
The process of soil formation as regulated by the effects of place, environment, and history
Pedogenesis
Five main soil-forming processes that give rise to different classes of soils
- Laterization
- Calcification
- Salinization
- Podzolization
- Gleization
it is a process common to soils found in humid environments in the tropical and subtropical regions
Laterization
What causes the rapid weathering of rocks and minerals?
Hot, rainy condiitons
Movements of large amounts of water through the soil cause heavy ____ and most of the compounds and nutrients made available by the weathering process are _____ ___of the soil profile if __ ___ __ by plants.
- leaching
- transported out
- not taken up
It occurs when evaporation and water uptake by plants exceed precipitation
Calcification
- It is a process that functions similarly to calcification, only in much drier climates
- It differs from calcification in that the salt deposits occur at or near the soil surface
Salinization
- acidic soil solution enhances the process of leaching, causing the removal of cations and compounds of iron and aluminum from the A horizon (topsoil)
- this process creates a sublayer in the A horizon that is composed of white- to gray-colored sand
Podzolization
it occurs in regions with high rainfall or low-lying areas associated with poor drainage
Gleization
The constantly wet conditions slow the breakdown of organic matter by ______ (bacteria and fungi), allowing the matter to ______ in ___ ___ of the soil. The accumulated organic matter releases ____ ___ that react with iron in the soil, giving the soil a ___ to ______ color matter
- decomposers
- accumulate in upper layers
- organic acids
- black to bluish-gray
