Review final

An accumulation of snow and ice, that lasts year round, and thick enough to flow downhill under its own weight (gravity)

Snowfall accumulates and survives
following summer

There are only two:
Mountain glaciers (Flow from high to low elevation)
Continental glaciers (Vast ice sheets covering large land areas  and Ice flows outward from thickest part of sheet)

Basal Sliding
Also known as basal slip
Basal →forming or belonging to a bottom layer
Significant quantities of meltwater forms at glacier base
Water decreases friction, ice slides along substrate

Move via Plastic Deformation
Below about 60 m depth (brittle/plastic transition)
Grains of ice change shape
New grains form while old grains disappear
Crevasses form at surface—upper zone is brittle (formed
due to stretching as glacier passes over convex slopes)

Zone of accumulation—area of net snow addition
Colder temperatures prevent melting
Snow remains across the summer months
Zone of ablation—
area of net ice loss

Accumulation - Advance

Ablation - Retreat

Erosional
Depositional

When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice

Soil Formation Factors
Natural Factors
Climate
Organics (biology)
Relief (slope steepness) and topography
Parent material (substrate composition)
Time
CLORPT
The Human Factor
Agricultural landscapes
Nutrient loss through leaching
Soil erosion

O Horizon
Mostly organic matter (e.g., decomposing leaves, soil
microorganisms)
Forms humus
20-30% or more organic matter
Different thicknesses
Able to retain water and nutrients

A Horizon
Topsoil (plows disrupt this zone)
Takes ~500 years to form 1”
Humus and clay particles provide
essential chemical links between
soil nutrients and plants
Dark in color
Rich organic compounds present

E Horizon
Light in color
Composed of coarse sand, silt
and resistant minerals
Fine particles removed by
*eluviation* (leaching, or removed
by water)
As rainfall increases, so does the
rate of eluviation

B Horizon
 Subsoil
 Reddish or yellowish
 Composed of accumulations of clays,
aluminum, and iron by *illuviation*
 In humid tropics, some materials in this horizon
may have formed in place from weathering
processes
 Caliche, or calcrete, in arid soils
* A, E, & B, soil horizons = Solum = true definable
soil of the profile*

C Horizon
The deposit at Earth’s surface
from which the soil developed
Parent material
Plant roots or soil
microogranisms are rare

R Horizon
Bedrock (e.g., granite, sandstone)
Could exist between <6 to 60 feet
below topsoil

Within a soil profile, soils
organized into distinct layers:
O, A, E, B

Distinguished base on: color,
texture, structure, consistence
(cohesiveness), porosity,
mineral content, moisture,
chemical processes

Ecology – study of relationships between organisms and
their environment and among the various ecosystems in
the biosphere
Biogeography – study of the distribution of organisms,
spatial patterns, and processes (physical and biological)

Abiotic (non-living organisms)
Sun, climate, and more (e.g., rain, temperature, soil, pollution)
Involve gaseous, hydrologic, and mineral cycles

Biotic (living organisms)
Primary producers (plants, cyanobacteria)

Habitat
 Type of environment where an organism resides (home)
 Includes both biotic and abiotic elements of the environment
 Size and character vary with each species needs

Niche
Function, occupation, or roll in which organisms fit into
their respective ecosystem
Determined by physical, chemical, biological needs of organism
Different from habitat, in that habitat is an environment that can
be shared by many species, whereas niche is the unique role
that a species performs within that habitat
Ex: Dung beetle consumes dung throughout life, store dung in
burrows, lay eggs in them which feed on it; in turn, performs a
unique role in its environment by aerating soil and releasing
nutrients

Takes place in structures within green leaves called
chloroplasts
Green pigment in chloroplast that are light sensitive is
chlorophyll

Respiration – the consumption of stored
energy (photosynthesis in reverse)
C6H12O6 + 6 O2 →6 CO2 + 6 H2O + heat
energy
Both photosynthesis and respiration
occur simultaneously in leaves
The balance of the two is called net
photosynthesis