Download Weathering and Soil Formation *** Practice Test

Earth’s Changing Surface
Chapter 2:
Weathering and
Soil Formation
*** Practice Test ***
Soil that is rich in humus can easily
support plant life is said to be _______.
Soil that is rich in humus can easily
support plant life is said to be fertile.
Plowing field along the curves of a
slope is called ___________.
Plowing field along the curves of a
slope is called contour plowing.
Living animals in the soil help the soil
by _______________________________.
Living animals in the soil help the soil
by mixing the soil and making humus.
What kind of weathering causes
mineral composition of rocks to
change?
What kind of weathering causes
mineral composition of rocks to
change?
Chemical weathering
Decomposers are the soil organisms
that _____________________________
_____________________.
Decomposers are the soil organisms
that break down and digest the remains
of dead animals.
How long did it take the thick, fertile
soil of North American prairies to
develop?
How long did it take the thick, fertile
soil of North American prairies to
develop?
Many thousands of years
What can cause the loss of soil that is
not protected by plant cover?
What can cause the loss of soil that is
not protected by plant cover?
Erosion by water or wind
One cause of mechanical weathering is
_________, or the wearing away of rock
by rock particles.
One cause of mechanical weathering is
abrasion , or the wearing away of rock
by rock particles.
When animals add their wastes to the
soil, then die and decay in the soil,
they are contributing to the formation
of _______________.
When animals add their wastes to the
soil, then die and decay in the soil,
they are contributing to the formation
of humus.
What ecological disaster occurred on
the Great Plains during the 1930s?
What ecological disaster occurred on
the Great Plains during the 1930s?
Dust Bowl (severe wind erosion of
prairie/farm soil)
What kind of weathering is caused by
plant roots and animal activity?
What kind of weathering is caused by
plant roots and animal activity?
mechanical weathering
Most of the work of mixing humus
within the soil is done by ____________.
Most of the work of mixing humus
within the soil is done by earthworms.
A permeable rock weathers easily
because it _____________________
__________________.
A permeable rock weathers easily
because it contains many small,
connected air spaces.
The particle size, or texture, of soil
determines _____________________
_______________.
The particle size, or texture, of soil
determines the amount of air and water
the soil can hold.
Ice wedging causes mechanical
weathering by means of ________
and ________ of water.
Ice wedging causes mechanical
weathering by means of freezing
and thawing of water.
Iron becomes soft and crumbly and
reddish-brown because it has been
chemically weathered by ________.
Iron becomes soft and crumbly and
reddish-brown because it has been
chemically weathered by
or oxidation.
oxygen
What agent of mechanical weathering
in which rock is worn down by a
grinding action?
What agent of mechanical weathering
in which rock is worn down by a
grinding action?
abrasion
The two most important factors in
determining the rate of weathering are
________ and _______.
The two most important factors in
determining the rate of weathering are
rock type and climate .
Soil formation begins with the
weathering of ____________.
Soil formation begins with the
weathering of bedrock .
Loam is made up of ____, ____, and
_____.
Loam is made up of silt , sand, and
clay.
In conservation plowing, why are dead
weeds and stalks of the previous year’s
crop left in the ground?
In conservation plowing, why are dead
weeds and stalks of the previous year’s
crop left in the ground?
to retain moisture and keep the soil in
place (prevent erosion)
The best type of soil in which to grow
plants is called ______________.
The best type of soil in which to grow
plants is called loam .
Uniformitarianism means that ________
___________________________________
_____________________.
Uniformitarianism means that the same
geological processes operate today
that operated in the past.
Compare and contrast topsoil and
subsoil.
Compare and contrast topsoil and
subsoil.
Both are made from minerals and rock
material weathered from bedrock.
Topsoil is darker and closer to the
surface and has more humus while
subsoil is below the topsoil and has
very little humus.
Describe three ways soil can be
damaged or lost.
Describe three ways soil can be
damaged or lost.
1. water erosion.
2. wind erosion.
3. exhausted by too much farming.
Bacteria and fungi in soil are called
_________________ because they break
down dead plants and animals.
Bacteria and fungi in soil are called
decomposers
because they break
down dead plants and animals.
Some plants produce acids that result
in ______________ weathering.
Some plants produce acids that result
in chemical weathering.
What is the most important factor in
causing marble statues to weather?
What is the most important factor in
causing marble statues to weather?
carbonic acid in rain water
Chemical weathering can be caused by
___________, or precipitation combined
with pollutants.
Chemical weathering can be caused by
acid rain , or precipitation combined
with pollutants.
Rock that contains tiny, connected
spaces through which water can move
is ____________.
Rock that contains tiny, connected
spaces through which water can move
is permeable.
One agent of chemical weathering is
_______________, which combines with
water to form H2CO3.
One agent of chemical weathering is
carbon dioxide, which combines with
water to form H2CO3.
Humus makes soil ________, or rich in
nutrients that plants need to grow.
Humus makes soil fertile , or rich in
nutrients that plants need to grow.
Humus is found in the ___ Horizon,
also known as ____________.
Humus is found in the A Horizon, also
known as topsoil.
The layer of soil containing fine
particles and minerals but little organic
matter is called the ___ Horizon, or
______________.
The layer of soil containing fine
particles and minerals but little organic
matter is called the B Horizon, or
subsoil .
Why is it important to aerate the soil?
Why is it important to aerate the soil?
Plant roots and soil animals need
oxygen and water in the soil. Loose
soil holds more air and water.
What is litter, in reference to soil
formation?
What is litter, in reference to soil
formation?
Layer of dead plant material (leaves
and stems) on the topsoil.
Describe two ways burrowing animals
enrich soil with substances that plants
need to grow.
Describe two ways burrowing animals
enrich soil with substances that plants
need to grow.
1. Add humus and nitrogen to the soil
with their waste.
2. Mix the soil with their digging.
What is crop rotation?
What is crop rotation?
When farmers plant different crops in
fields every year to keep the soil from
being depleted or exhausted by using
up the same nutrients year after year.
Explain how every living thing on land
depends on soil.
Explain how every living thing on land
depends on soil.
Plants (producers) need the soil and
all animals (consumers) need the
plants for food and oxygen.
Who was George Washington Carver?
Who was George Washington Carver?
(1864-1943) He taught new methods of
soil conservation and encouraged
farmers to plant peanuts to restore soil
fertility.
Describe how freezing and thawing of
water causes mechanical weathering.
Describe how freezing and thawing of
water causes mechanical weathering.
Water seeps into cracks in the rocks
and then freezes causing expansion
which causes the rock to crack more
and allow more water into the rock.
How is bedrock related to topsoil?
How is bedrock related to topsoil?
The rock particles and minerals in the
topsoil come from weathered bedrock.
Consider the importance of rain forests,
coral reefs, and topsoil. Which do you
think is more important to a healthy
biosphere on the Earth?
Consider the importance of
ecosystems located in rain forests,
coral reefs, and topsoil. Which do you
think is more important to a healthy
biosphere on the Earth?
Any choice could be valid. Give your
opinion and support it with facts.