refers to a class of animals that spend part of their time on
land and part in the water; they are an intermediate form between
fishes and reptiles. Members of this class include frogs, toads,
study of the distribution of different species of organisms
around the planet and the factors that influenced that distribution.
study of the universe's origin, structure, and evolution; a
theory of the origin and structure of the universe.
molecular weight organic acids resulting from plant decay.
molecular weight organic acids which can be extracted from soils
and near-surface sediments with aqueous base. They are derived
from the decomposition products of plant and bacterial remains.
branch of physical geography concerned with the behavior of
water in the atmosphere, on the surface of the earth and underground.
The science dealing with the properties, distribution and
circulation of water.
to liquids (especially water) in motion and the mechanics
of that motion.
algae (green, blue-green and red algae)
member of the macroscopic plant life of an area, especially
of a body of water; large aquatic plant.
enough to be observed by the naked eye
section of a mountainous region below the timberline having
cool, moist temperatures and dominated by evergreen trees
(including the climate, plant life, air water, minerals, organisms,
etc) in the geologic past, that is the period of time extending
from the formation of the earth to the present
average state or typical conditions of climate during some
past geologic period.
branch of science dealing with causes of climatic changes;
relationships between climate and sedimentation; climatic
factors and the geological record.
of past events, particularly prehistoric.
branch of science dealing with microscopic, decay-resistant
remains of certain plants and animals, particularly pollen
and spores, living and fossil.
reduced plant or wood material, containing approximately 60
percent carbon and 30 percent oxygen. An intermediate material
in process of coal formation.
structure with the capacity to give rise to a new plant, e.g.
a seed, a spore, or a part of the vegetative body capable of
independent growth if detached from the parent.
grassy, rushlike or flaglike plants growing in wet places
configuration of a land surface, including its relief.
because of unusual topography and groundwater inputs that supplement
that is cloudy with suspended particles
of transparency of fluids due to their light-scattering suspended