Deserts

Stephen KozlowskiMarshall PlumleyDmitriy Adamia

What is a Desert?

• Deserts cover over 1/5 of Earth’s surface • Less than 50cm of precipitation annually– Some deserts receive less than 1.5cm

• Very little/no vegetation• Not restricted by latitude or elevation• Deserts are second only to tropical rain forests

in the variety of plants and animals that live there

Different Types of Deserts

• Different categories:– Hot and Dry: Generally warm throughout the year, extremely

hot summers, very little, if any, vegetation, found in inland equatorial/tropical regions

– Semiarid: Long, dry summers (sometimes has monsoon season), sparse vegetation and animal life

– Coastal: long, warm summers, cooler winters, some shrubs– Cold: widely scattered plant life (some deciduous and lichen

plant life) , almost no life at higher latitudes/elevations, cold summers , very long, cold winters.

Hot Dry Desert

• Very low precipitation (generally under 1.5cm annually)• Virtually lifeless• Animals are mainly nocturnal, and burrow during the day

to keep out of the heat and to conserve water, usually coming out at dusk or dawn to graze during the cooler parts of the day– Insects, birds, and small animals (like lizards, mice/rats, foxes)

are dominant species• Plants are generally low-lying shrubs and short trees with

water-conserving capabilities (small, thickly coated leaves, or spines on cacti)

Sahara Desert Gobi Desert

Semiarid Desert

• Moderately long, dry summers with a rainy season, with concentrated storms (monsoons) that bring 2-4 cm annually

• Much more lively than the hot dry desert• Animals are similar to hot dry, with he majority being small

animals like jackrabbits, mice/rats, lizards, though the semiarid has a greater population of large animals, with deer-like animals (white tailed deer, antelope) and mountain lions

• Vegetation often has traits to keep it safe from the hazardous environment (spines on a cactus, thorns on trees) and to reduce transpiration; most of the leaves have reflective attributes to reduce water loss, and produce odors of undesirable tastes (coyote melon, creosote)

Baja California Sonoran Desert

Coastal Desert• Cold Current from Ocean suppresses rain fall; the Atacama desert has the lowest

precipitation, but remains cool because of this type of phenomena– Average annual rainfall is 8-13 cm

• Majority of moisture is received from fog• Mainly large rock formations and sand dunes• Vegetation is adapted to be able to soak up lots of moisture and store it for later use;

some plants have extensive, shallow root networks in the soil to take in as much water as possible– Several types of bushes and grasses are found in this type of desert, with a much smaller

amount of trees• Very specialized animals live in this type of desert, most of which go dormant during

the long, waterless summers (toads that seal themselves in a burrow with some kind of gelatinous secretion can remain inactive for 8-9 months; some insects lay eggs that are dormant until the environment produces the necessary conditions for them to hatch and live; fairy shrimps similarly lay dormant eggs). Other animals include coyotes, badgers, various birds and reptiles

Atacama desert Namibia’s Coastal Desert

Cold Desert

• Long, very cold winters, with short, moist summers. Annual precipitation is 15-26 cm.

• Only a small amount of plants and animals can survive in a cold desert– Most plants are deciduous or lichens, and are widely

scattered, thus, there is a wide distribution of animal life throughout the land

– Like the other deserts, the majority of animals are burrowers, and there are more small animals (mice, ground squirrels) than the large animals (antelope)

Arctic Desert White Desert

Bibliography

• http://www.saskschools.ca/~stmarypa/bio20/biology20deserts/sld001.htm

• http://www.ucmp.berkeley.edu/exhibits/biomes/deserts.php