Bio 307 exam 2

igneous, sedimentary, metamorphic

Give three ways in which rock are formed

Biological growth and decomposition, climate, biotic factors, topography, time

Give four ways parent material may be broken down or added to soil

Occurs due to the products released by plants and lichens by acid rainwater

How does chemical weathering of parent material occur

Till

Parent material added by glaciers or rivers

Loess

Parent material added by wind

Contribute to the breakdown of parent material, and also accumulate humus

What role does biological growth and decomposition play in soil formation

Humus

organic, dark material remaining after decomposition by microorganisms

Influences the nature of the biotic interactions within the soil, also directly influences the accumulation of soil parent material and different soil layers

What role does climate play in soil formation

Animals, bacteria, and fungi all contribute to the formation of soil, Vegetation is largely responsible for organic matter in the soil, color of soil, and the nutrient content in the soil

What role do biotic factors play in soil formation

Influences the amount of water that enters the soil influences the rate of erosion and downhill transport of soil material

How does topography affect soil ecology

O horizon

surface layer resting on a mineral layer composed of fresh or partially decomposed organic material that has not been mixed into the mineral soil

Oi and Oa Layer

Layer consisting of partially decomposed organic matter

A horizon

Upper layer of mineral soil is characterized by an accumulation of humus

B horizon

Zone of extensive illuviation, a deposit of materials that leaked out of the A zone (silicates, clay, iron, aluminum, and humus)

C horizon

Layer that consists of primarily weakly weathered material which resembles parent material

R horizion

Layer of unweathered parent material, bedrock

Eluviation

transport of soil material from upper layers of soil to lower layers of soil

Illuviation

the accumulation in a lower soil horizon of materials brought down from upper horizons

It can tell you about the amount of organic material, iron oxides, and drainage and aeration

What does the color of the soil tell you?

Dark brown to black

Color of soil with large amounts of organic material

Red to yellow

Color of soil in presence of iron oxides, and good drainage and aeration

Gravel

Not considered part of the fine fraction of soil

Sand

Most easily seen fine soil, feels gritty to touch

Silt

Scarcely seen by human eye, looks and feels like flour

Clay

Finest soil, cannot be seen with a microscope. Plasticity is its most important property

Depends on slope, vegetation, weathering, and parent material

How does soil differ from one place to another

Field Capacity

The maximum amount of water the soil can hold following drainage of gravitational water flow

Permanent wilting point

the soil dries out to a point at which plants are unable to absorb enough water to replace that lost by evapotranspiration

Soil micelles

Complexes of humus and clay that limit ion mobility

Contain aluminum, silica, and oxygen arranged in tetrahedral patterns

What elements do clays possess

Isomorphous substitution

Ability to change shape when pressure is applied and retain shape when pressure is removed

Percent base saturation

percentage of sites occupied by ions other than hydrogen

Hydrogen atoms are added by rain water, acids from organic matter, and by metabolic acids produced by microorganisms and plants

How does soil become more acidic over time?

High acidity leads to aluminum toxicity, which kills plants

How does low pH in soil affect plants

It is relatively stable structurally and chemically, underground climate is less variable than above, atmosphere mostly remains saturated with water

Give three characteristics of soil that make it a good place for organisms to live

soil particles hamper movement, and most organisms must depend on pore space because it determines the availability of living space, humidity and oxygen

What are some problems of living within the soil

Arctic

Cold and dry

Alpine

Lower latitude, develops on mountains

Cryoplanation

Tundra shaped by continual freezing and thawing expanding of the soil layers - creates frost hummocks

Frost hummocks

Small earthen mounds and stone polygons formed from cryoplanation

Permafrost

Ground that is permanently frozen

Solufluction terraces

Supersaturated soils that creep downward over the underlying permafrost

Krummholz

Transition zone between forest and tundra, found south of artic tundra and below alpine tundra, has gnarled trees

Muskeg

grassy flooded bogs in boreal/ north coniferous forest

Temperate rainforest

parallels the Pacific coast from Alaska to California It includes some of the world's tallest trees such as Sitka spruce, western hemlock and redwoods, that are prized for their value as lumber

Pinon-Juniper Woodland

open growth of small trees with a well developed understory of grasses and shrubs

Along the coastal plains of South Atlantic and Gulf States, used for paper products

Where are southern pine forests found?

temperate deciduous forest

Most wide spread forests require fairly high rainfall that falls throughout the year Trees lose their leaves in fall as protection against cold and water loss during winter when water is frozen and therefore unavailable

Valuable wood, make space for mining, raising cattle

Why are tropical rainforests being cleared?

Due to the leaching of nutrients from the high rainfall and the fact that decomposers rapidly break down organic matter and return it quickly to existing plants

Why are soils in tropical rainforests poor?

Lianas

Climbing woody vines that drape rainforest trees.

Epiphytes

Photosynthetic plants that grow on other trees rather than supporting themselves

Prairies, steppes, pampas, veldt

Give four names for grassland communities

Tallgrass prairie

extends from the forest- grassland ecotone in Wisconsin, Indiana and Illinois tall grass has been converted to farmland, trees and shrubs common along streams

Short grass prairie

West of the tallgrass region is a grassland ecotone called the mixed-grass prairie Which gives way to shallow-rooted short grasses that eventually grades into desert or forest at higher elevations short grasses must use moisture in the upper soil layers beneath which is a permanent dry zone into which the roots do not penetrate

Tropical Savanna

grasslands with varying degrees of tree and shrub cover growing in soils low in nutrients and moisture Africa, South America and Australia

well adapted to surviving periodic fires and low soil nutrient levels Shrubby vegetation covers large portions of arid and semiarid land

What are shrubs?

Mediterranean Climate

mild rainy winters and long, hot dry summers support a growth of tough, small broadleaf shrubs and trees with heavily waxed leaves that grow together

Chapparal biome

covers over six million acres of southern California hillsides dry shrublands normally lack a well-developed understory and much ground litter, they are still highly flammable!

Northern desert shrub community

continental climate with hot summers and prolonged winters arid Great Basin of North America

Temperature inversion

warm air floats over cold as the atmosphere is cooled from below

Rain shadow deserts

moist air descends on the leeward (down wind) side of the mountain, the air will be heated and dried

Arroyos

Deep canyons

Washes

Large river beds

Littoral zone

shallow, well-lit waters close to shore

Limnetic zone

open sunlit waters from outside the littoral zone where photosynthesis is impossible

Profundal zone

Deep open water below the depth of effective light penetration

Benthic zone

Bottoms of lakes and ponds, rich organic matter

Limnology

study of freshwater ecosystems

Lentic

standing water habitats

Lotic

running water habitats

Plankton

Tiny organisms that float in the water

Nekton

free-swimming animals that can move throughout the water column

Neuston

Organisms that live right at the sea surface but remain underwater

Phytoplankton

Base of food chain

Zooplankton

small free-floating animals that eat phytoplankton

Epilimnion

Upper, photosynthetic organisms

Hypolimnion

Beneath epilimnion, cut off from surface air, constant contact with mud and nutrients

Metalimnion

Between epilimnion and hypolimnion, steep temperature gradient, thermocline

BOD

biological oxygen demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials

Oligotrophic lakes

nutrient-poor and generally oxygen-rich

Eutrophic lakes

Nutrient rich, oxygen poor, warm, plants

Redox-potential of lake sediments

If oxygen is oxidized in the mud, it is insoluble and unavailable, if it is reduced in the mud it is available to nutrients

Fall turnover

a mixing of the lake waters in temperate lakes, caused by falling temperatures in autumn, warmest water near the bottom

Spring turnover

mixing of lake waters in the spring due to wind and warming lake temperature, warmest water is at the top

Stratification in temperate lakes

Waters freeze from top-down, as ice forms on top and fish can survive further down

Riffles

shallow areas of swiftly flowing water

Pools

Deep water flowing slowly over smooth sandy, muddy bottom

Runs

fast flowing stretches of streams over bedrock or rock and sand with smooth surface water

Aufwuchs/periphyton

Mat of photosynthetic organisms

Basin wetlands

shallow basins ranging from upland topographic depressions to filled in lakes and ponds

Riverine wetlands

develop along shallow and periodically flooded banks of rivers and streams.. River bottoms

Fringe wetlands

coastal areas of large lakes or at edge of marine estuaries

Marsh

a wetland typically covered with grasses

Swamp

A wetland ecosystem in which shrubs and trees grow

Life on sandy shores

difficult, little surface area for attachment, organisms must be buried in sand or mud, deposit or filter feeders

Life on rocky shores

create tide pools, diversity, sudden fluctuations in temperature and salinity

Type of water in coral reef

Warm, nutrient poor waters, activities of tiny coral animals

Zooxanthellae

within the cells of coral polyps which can undergo photosynthesis and transfer organic material to tissue, deposit calcium carbonate

Estuaries

Partly enclosed coastal ecosystems where ocean meets land, seawater mixes with freshwater, nutrient rich, productive