BIOME PROJECTTHE DESERT

An Elliot-Asaf Production

What is a Desert?• A biome in which evaporation exceeds precipitation and

the average amount of precipitation is less than 10inch per year.

• Deserts have little vegetation or have widely spaced mostly low vegetation.

• The desert exhibits extremes in temperature, the temp rises to sweltering levels during the day and reaches cold temps at night.

World Distribution of Deserts• 30% of earths surface is Desert! They are situated between tropical and

subtropical regions north and south of the equator.• The largest deserts are in the interiors of the continents far from moist air

carried by the sea.

Climatogram• The graph shows the average rainfall and temperature of the biome,

per month• The graphs shows very high temperatures a very low levels of

precipitation

Three Types of Desserts

Three types of Deserts• Tropical-ex Sahara, high temp, little rainfall

(1-2months/year) sparse plant-life and rife with rocks.• Temperate Deserts-ex Mojave, daytime temps are high

in summer and low in winter. More precipitation than tropical deserts. Sparse vegetation/ mostly shrubs and cacti and very little animal species.

• Cold Deserts-Winters are cold, summers are warm/hot, and precipitation is low.

Plant and Animal species Food Web

How do plants survive in the desert

• Barrel Cactus• Having no leaves• Storing water and synthesizing food in their expandable, fleshy tissue• Reducing water lass by opening their pores to take up CO2 (for photosynthesis) only

at night

Apache BloomWax coated leaves that minimize transpiration Using deep roots to tap into groundwater

OctilloUse widely spread shallow roots to colect water after brief showers and store it in their

spongy tissueDrop their leaves to survive in a dormant state during long drying spells

How do Plants Survive ?(cont)• Devils Claw-Become dormant during dry periods, uses deep roots to

tap into ground water

Organ Pipe- Stores water within fleshy leaves. Stores biomass in seeds during day periods.

Common animals in desert!• Black-Collared Lizards:

• Coyote:

• Rattle-snakes

• Scorpion:

• Cactus Wren:

And don’t forget The jabster

How Animals Survive?• Hiding in cool burrows or rocky crevices by day and coming out at

night or in early morning.

• All animals have physical adaptations to conserve water. Insects and reptiles have thick outer coverings to prevent water loss. There feces is dry in to conserve water.

• The animals obtain water from the food they eat, many insects and small animals obtain water from dew that accumulates over night.

• Most animals are dormant during the periods of extreme heat

Desert Soil

• Very poorly developed• Large quantity of mineral particles.• Low amount of organic matter.-caused by low

plant productivity. Which is intern caused by the arid climate.

• The soil cannot retain a large amount of water. The high level of evaporation (due to heat) brings salt to surface which greatly impedes plant growth.

Common Abiotic Features

• Temperature• Soil• Precipitation (lack of)• Topography

Ex of Symbiotic relationship (mutuality)

• Between Yucca Moth and Yucca Plant• Yucca Moth pollinates the Yucca Plant

and the Yucca Plant provides a safe haven for the moth to lay eggs.

Environmental Degradation Of desert Biome

• Caused mainly by human cultivation of desert Biome• The already weak soil is being increasingly degraded by vehicles

and urban development.• The desert is used to store radioactive waste and to test

underground nuclear weapons. These cause the soil to become poisonous and kills many life forms that inhabit such areas within desert.

• Humans are depleting the deserts underground water supply to support urban-desert cities, this takes away the necessary water needed for desert animals and plants to survive.

Human Impacts on Deserts• Large desert cities• Soil destruction by vehicles and urban development• Depletion of underground water supplies• Land Disturbance and pollution from mineral extraction• Storage of Toxic and Radio-active waste• Large arrays of solar cells and solar collectors used to

produce electricity• Deserts require an extensive period of time to recover

due to their slow plant growth, low species diversity, slow nutrients cycling, and water shortages.

Sources

• www.blueplanetbiomes.org/desert.htm • www.wikipedia.com/desert/biome/.htm• www.desertusa.com/animals.html• Miller, Arthur. Living in The Environment• www.livingdesert.org/