Chapter 2 Flashcards
A horizon
biologically active soil layer consisting of mixture of mineral materials, such as clay, silt and sand, as well as organic material, derived from overlying O horizon
B horizon
subsoil in which materials leached form above accumulate.
-may be rich in clay, OM, iron and other materials
biome
distinguished primarily by their predominant plants and are associated with particular climates.
-consist of distinctive plant formations
boreal forest
(taiga) - northern forests that occupy the area south of arctic tundra.
- though dominated by coniferous trees they also contain aspen and birch
caliche
calcium carbonate rich hardpan soil horizon; extent of caliche formation can be used to determine age of desert soils
C horizon
soil layer composed of largely unaltered parent material, little affected by biological activity
climate diagram
standardized form of representing average patterns of variation in temperature and precipitation that identities several ecologically important climatic factors such as relatively moist periods and periods of drought
Coriolis effect
phenomenon caused by rotation of earth, which produces a deflection of winds and water currents to the right of their direction of travel in the N. Hemisphere and to the left in the S. Hemisphere
desert
arid biome occupying ~ 20% of land surface of earth in which water loss due to evaporation and transpiration by plants exceeds precipitation during most of year
drought
extended period of dry weather during which precipitation is reduced sufficiently to damage crops, impair functioning of natural ecosystems, or cause water shortages for human pops.
lithosol
soils very low in OM and composed of rock frags
Mediterranean woodland/shrubland
biome associated with mild, moist winters, dry summers, between 30 and 40 degrees latitude.
- vegetation; small, tough leaves and adaptations to periodic fire
- found in Mediterranean sea, chile, S. Australia, s. Africa
mycorrhizae
mutualistic association between fungi and roots of plants
natural history
study of how organisms in a particular area are influenced by factors such as climate, soils, predators, competitors, and evolutionary history
O horizon
most superficial soil layer containing substantial amounts of OM, including whole leaves, twigs, other plants parts, highly fragmented OM
palmer drought severity index
index of drought that uses temperature and precipitation to represent moisture conditions in a region relative to long term average temp and precip within the region
sample mean
average of a sample of measurements or observations; an estimate of true pop mean
solifluction
slow movement of tundra soils down slopes as a result of annual freezing and thawing of surface soil and the actions of water and gravity
temperate forest
deciduous or coniferous forests generally found between 40 and 50 degrees latitude, where annual precip is 650 to 3000 mm
-this biome receives more winter precip than temp. grasslands
temperate grasslands
grasslands growing in middle latitudes that receive 300 and 1000 mm annual precip with max precip in summer
tropical dry forest
broadleaf deciduous forest growing in tropical regions having pronounced wet and dry season; trees drop their leaves during dry season
tropical rain forest
broadleaf evergreen forest growing in tropical regions where conditions are warm and wet year round
tropical savanna
tropical grassland dotted with scattered trees; characterized by pronounced wet and dry season and periodic fires
tundra
northern biome dominated by mosses, lichens and dwarf willows, receiving low to moderate precip and having very short growing season
