Deserts 101
Transcript
Wind whips over a barren wasteland.
Vast nothingness as far as the eye can see, or so it may seem.
Creatures peek out of burrows, scurry across the sand, and soar through the sky, revealing a landscape not as lifeless as it might first appear.
Deserts are often defined as areas of land that receive less than 10 inches of rainfall each year.
These regions are low in humidity and can even be moisture-deficient, evaporating water faster than it is received.
While most deserts are found in the mid-latitudes, these diverse ecosystems occur on all seven continents and make up nearly one-third of Earth’s total land mass.
Deserts are sometimes classified into four major types: subtropical, semiarid, coastal, and polar.
Subtropical deserts are found along the equator, and the Tropic of Cancer, and the Tropic of Capricorn.
They are the hottest deserts on Earth, with daytime temperatures that can reach up to 120 degrees Fahrenheit.
Semiarid deserts are located in Asia, Europe, and North America.
These cold-winter deserts often form when tall mountain ranges block moisture through a process called the rain-shadow effect.
Coastal deserts form alongside the tropical western edges of certain continents.
Despite their proximity to water, coastal deserts remain dry.
Polar deserts are found in the Arctic and Antarctic.
The other end of the extreme, winter temperatures in the Antarctic Desert average around minus 50 degrees Fahrenheit.
While deserts experience extreme temperatures and receive very little precipitation, they are still important habitats for plants and animals.
Desert animals, such as the coyote, have evolved to withstand harsh desert conditions by burrowing into the cool ground and emerging at night, when desert temperatures drop.
Many desert plants, including the saguaro cactus, have established long and shallow root systems to better absorb what minimal moisture might be present in the ground.
Highly specialized to survive in such a harsh environment, desert wildlife is particularly vulnerable to ecological changes.
Existing deserts have become less habitable because of rising temperatures that dry up scarce water resources and increase the risk of wildfires.
Additionally, new desert areas are beginning to form through desertification.
This phenomenon occurs when factors such as deforestation, climate change, and resource mismanagement degrade the biological productivity of a region, thereby creating a desert.
For instance, in Central Asia, poor irrigation practices and excessive water usage dried up the Aral Sea and formed the youngest desert on the planet.
But by practicing responsible agriculture, better management of limited water resources, and limiting further development, it may be possible to curb desertification while protecting our surprisingly rich desert ecosystems.
Vocabulary List
whip
(verb) to move quickly and forcefully
barren
(adjective) having no or few plants growing on it
vast
(adjective) very large
peek
(verb) to look at something quickly and secretly
burrow
(noun) a hole or tunnel dug in the ground by an animal for shelter
scurry
(verb) to move quickly with short steps
soar
(verb) to fly high in the air
reveal
(verb) to make known or show something that was previously hidden or unknown
lifeless
(adjective) dead; not showing any signs of life
deficient
(adjective) lacking in something essential or necessary
diverse
(adjective) showing a great variety
mountain range
(noun) a group of mountains or hills, usually in a line
coastal
(adjective) situated on or near a coast
proximity
(noun) the state of being near or close
average
(verb) to usually be a particular size or amount
precipitation
(noun) the process of water falling to the ground from the atmosphere, especially in the form of rain, snow, sleet, or hail
evolve
(verb) to develop gradually over a period of time
withstand
(verb) to be able to resist or tolerate something, especially something unpleasant or difficult
harsh
(adjective) severe or unkind
burrow
(verb) to dig a hole or tunnel in the ground
particularly
(adverb) especially; more than usual or more than others
vulnerable
(adjective) easily harmed or hurt
habitable
(adjective) suitable for people to live in
scarce
(adjective) not plentiful or abundant
degrade
(verb) to make or become worse in quality, condition, or standard
excessive
(adjective) more than is necessary, normal, or desirable
curb
(verb) to control or restrain something
Grammar Lesson
In this lesson, we will learn:
- how to use while
WHILE
While deserts experience extreme temperatures and receive very little precipitation, they are still important habitats for plants and animals.
While is:
- a conjunction (subordinating conjunction)
- a noun
- a verb
while (1)
(conjunction) during the time that something is happening
subject + verb + while + subject + verb
Someone called while you were out.
someone called = independent clause
while = subordinating conjunction
you were out = dependent clause
while + subject + verb + comma + subject + verb
While you were out, someone called.
When a sentence starts with a subordinating conjunction, we need a comma after the dependent clause.
while (2)
(conjunction) used to highlight the contrast of two things
subject + verb + comma + subject + verb
The first two services are free, while the third costs $25.00.
For this meaning, we use a comma even though while is not at the beginning of the sentence.
while (3)
(conjunction) although
while + subject + verb + comma + subject + verb
While I like Tim personally, I don’t think what he’s doing is right.
= Although I like Tim personally, I don’t think what he’s doing is right.
For this meaning, while is usually used at the beginning of the sentence.
while (4)
(noun, singular) a period of time
subject + verb + a while
This could take a while.
subject + verb + for a while
We talked for a while.
subject + verb + in a while
I’ll see you in a while.
subject + verb + after a while
He started to relax a bit after a while.
while away (5)
(phrasal verb) to spend time in a pleasant and lazy way
subject + while away + noun + -ing form
He whiled away the hours watching old movies.
They whiled away the time playing board games.