Transcript Texas Ecoregions

TEXAS
ECOREGIONS
7.8B: I can analyze the effects of
weathering, erosion, and deposition on the
environment in ecoregions of Texas
WHAT IS AN ECOREGION?
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Ecoregion - a major ecosystem (smaller than a
biome) with distinct geography, plants and animals,
and receives uniform solar radiation and moisture
IN THE NATURAL WORLD, ENVIRONMENTS ARE
CHARACTERIZED BY:
 Types
of soil
 Precipitation
 Temperature
 Land features
 Vegetation
 Animal wildlife
MECHANICAL/PHYSICAL WEATHERING
 Mechanical
or physical weathering is the
process by which rock is broken down into
smaller pieces by physical changes.
MECHANICAL/PHYSICAL WEATHERING
Some ways that rock can be broken down physically
include:
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Temperature Change – a rise in temperature will cause a
rock to expand and a decrease in temperature will cause a
rock to contract. Repeated changes in temperatures will
cause the rock to crumble.
Abrasion – rock can be broken down by the action of other
rocks; wind, water, glaciers, and gravity carry different
sized pieces of sediment that can strike a rock causing it
to break apart or wear down.
Animal Action – animals digging and burrowing can cause
rock to break apart of become more exposed to other
agents of weathering.
Plant Growth – roots of plants break apart rock as they
grow and increase in size
CHEMICAL WEATHERING
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The breakdown of rocks by
chemical reactions. Occurs
more often in locations with
high precipitation rates and
high temperatures.
 Oxidation
– when materials in
rock react with the oxygen in
air or water causing a change.
(ex. rusting and corchemical
rosion).
 Acid
Rain – Some acids form naturally when
chemical in the atmosphere combine with water in
the air and cause acid precipitation. The acid rain
weathers rock and changes its composition.
 Acids from organisms - Lichen and mosses produce
weak acids that break down the rock that they grow
on.
EROSION
Erosion is the process by which
weathered rock pieces are carried
away.
 During the process of erosion,
sediment is removed from one area on
Earth’s surface and carried to another.
 Erosion is reduced by vegetation (plant
life).
 Agents of erosion include the following
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– Moving water – Wind – Glaciers –
Gravity
DEPOSITION
Deposition the placement of sediment
after being carried from place of origin
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Some formations due to deposition are…
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Floodplains – the sediment that is deposited after flood waters
recede
Deltas – when a river flows into an ocean, the river slows down
and deposits the sediment it was carrying
Alluvial fans – when a stream flows down hill onto a flat land
surface, the sediment forms a fan-shaped deposit –
Beaches – when water moves down hill and meets a
nonflowing body of water, it slows down and deposits the
sediment. Waves also help shape the beach.
Dunes – when wind carrying sand is blocked by an upward
slope, it slows down and deposits the sediment, causing the
sand to pile up
WHAT IS THE TOPOGRAPHY OF THE ECOSYSTEMS?
WHICH ECOREGIONS HAVE THE MOST PRECIPITATION?
WHAT EFFECT COULD THAT HAVE ON VEGETATION?
ON EROSION AND DEPOSITION?
1. PINEY WOODS
Due to abundant
precipitation and
abundant vegetation
that holds the soil in
place, there is very
little erosion.
 Thick vegetation near
rivers
inhibits/prevents river
erosion.
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2. OAK WOOD & PRAIRIES
Has gently rolling hills
and lightly wooded
plains.
 moderate rainfall that
helps shape the land.
 Trees and grasses
prevent large amounts
of soil erosion due to
water and wind.
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3. BLACKLAND PRAIRIE
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nutrient-rich soils
receive good amounts of
rainfall through the year.
If the land is clear-cut of
natural vegetation for
construction, nutrients
can easily be eroded.
If the land is used for
farming and it is not
managed well, nutrients
will be quickly used up.
4. GULF COAST PRAIRIES/MARSHES
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Wave action, a cause of
weathering, erosion and
deposition, is constant along
the Texas Coastline.
Sediments are weathered and
eroded along beaches and
carried out into the ocean to
form barrier islands (like
Galveston).
Can have extensive flooding
from storms and hurricanes
Estuaries (salt and fresh water
meet)
HOUSTON is in this ecoregion!
5. COASTAL SAND PLAIN
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Soil in the region is
primarily sand-based.
If there isn’t enough
vegetation to keep the
soil in place, rainfall
received can cause
severe erosion.
Catastrophic events
such as hurricanes can
increase wave erosion
and deposition.
6. SOUTH TEXAS BRUSH COUNTRY
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The area is known as
“Brush Country” due to
the shorter trees and
many shrubs.
Overgrazing of the land
has allowed nutrient-rich
topsoil to erode way.
Runs from edges of the Hill
Country to the Lower Rio
Grande Valley
Mostly dry and covered
with grasses and thorny
brush prickly pear cacti
7. EDWARDS PLATEAU
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Erosion has left most of
the region with very
shallow soils (less than
10 inches) lined with
limestone rock layers.
High amounts of rain in
a short amount of time
can cause flash
flooding.
Rainwater mixes with
carbon dioxide in the
atmosphere and soils to
form carbonic acid, which
acts to dissolve away
limestone.
8. LLANO UPLIFT
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The soil is not as prone to
flooding because it allows water
to infiltrate very easily 
Underground lakes in the
Edward’s Aquifer area
The region is described as
rough, hilly terrain.
The weathering has exposed the
granite dome underneath 
Enchanted Rock (Austin area)
Plant roots causes mechanical
weathering in this region
9. ROLLING PLAINS
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Soils in this area are
most fertile and
sought after for crop
production.
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Periods of drought
and then sudden
increase in rainfall
causes large amounts
of erosion and
deplete the soil of
nutrients.
10. HIGH PLAINS
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“Texas Panhandle”- is on a high,
flat plateau.
Largest and most completely flat
areas of its size in the world!
Mostly flat and grassy, treeless
The region extends to the Palo
Duro Canyon-the nation’s 2nd
largest canyon.
Palo Duro Canyon was formed by
water erosion from the Red River.
The water deepens the canyon by
moving sediment downstream.
Wind and water erosion gradually
widen the canyon over long
periods of time.
11. TRANS PECOS
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Desert portion” of Texas. Hot dry
desert that is cool at night
bedrock has a large amount of
calcium.
Home of the tallest mountain in
Texas, The Guadalupe Peak.
(8,749 feet).
Pines and Oaks dominate the
tree species.
Soils are shallow and rocky.
Soils in the canyon bottoms
and valleys are deeper as a
result of deposition.
TRANS PECOS
12. MARINE ENVIRONMENT
Marine topography refers to the shape the land
along coastlines, but they occur also in significant
ways underwater.
 The effectiveness of marine habitats is partially
defined by these shapes, including the way they
interact with and shape ocean currents.
 Marine topographies include coastal and oceanic
landforms ranging from coastal estuaries (where
freshwater and saltwater meet) and shorelines to
coral reefs.
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