Transcript desert - JBHA-Sci-US-tri1

BIOME PROJECT
THE 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
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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 (12months/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
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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 Bloom
Wax coated leaves that minimize transpiration
Using deep roots to tap into groundwater
Octillo
Use widely spread shallow roots to colect water after brief showers and store it in their
spongy tissue
Drop 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
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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
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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
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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/