Human Survival in the Desert
Basic Desert Facts <ul><ul><li>Sub-deserts: since these areas are not truly a hyperarid climate they are called pseudodese...
Continued <ul><ul><li>Temperatures exhibit daily extremes because the atmosphere contains little humidity to block the Sun...
Continued <ul><li>Canopy in most deserts is very rare. Plants are mainly ground-hugging shrubs and short woody trees. Leav...
What Happens to the Body in Extreme Heat? <ul><li>People suffer heat-related illness when their bodies are unable to compe...
Continued <ul><li>Heat Stroke- Heat stroke occurs when the body is unable to regulate its temperature. The body's temperat...
Continued <ul><li>Heath Cramps- Heat cramps are muscle pains or spasms usually in the abdomen, arms, or legs that may occu...
Body Systems Affected   <ul><li>The Cardio Vascular System-Blood pressure increases, blood thickens due to the removal of ...
Adaptations <ul><li>The bodies first line of defense is sweat. When the body reaches a certain temperature water is releas...
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Desert Power Point

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Desert Power Point

  1. 1. Human Survival in the Desert
  2. 2. Basic Desert Facts <ul><ul><li>Sub-deserts: since these areas are not truly a hyperarid climate they are called pseudodeserts.(The Great Victorian Desert, The Chihuahuan Desert) These areas have more permanent vegetation than true deserts including trees and large shrubs. The average rainfall in these areas is typically 4-16 inches per year. </li></ul></ul><ul><ul><li>True Deserts-These are deserts typically characterized like by the great sand dunes of the Arabian Desert. These hyperarid areas receive less than 4 inches of rain per year causing very little permanent vegetation. </li></ul></ul>
  3. 3. Continued <ul><ul><li>Temperatures exhibit daily extremes because the atmosphere contains little humidity to block the Sun's rays. Desert surfaces receive a little more than twice the solar radiation received by humid regions and lose almost twice as much heat at night. Many mean annual temperatures range from 20-25° C(68-86 degrees Fahrenheit) . The extreme maximum ranges from 43.5-49° C. Minimum temperatures sometimes drop to -18° C. </li></ul></ul><ul><ul><li>Soils are course-textured, shallow, rocky or gravely with good drainage and have no subsurface water. They are coarse because there is less chemical weathering. The finer dust and sand particles are blown elsewhere, leaving heavier pieces behind . </li></ul></ul>
  4. 4. Continued <ul><li>Canopy in most deserts is very rare. Plants are mainly ground-hugging shrubs and short woody trees. Leaves are &quot;replete&quot; (fully supported with nutrients) with water-conserving characteristics. They tend to be small, thick and covered with a thick cuticle (outer layer). In the cacti, the leaves are much-reduced (to spines) and photosynthetic activity is restricted to the stems. Some plants open their stomata (microscopic openings in the epidermis of leaves that allow for gas exchange) only at night when evaporation rates are lowest. These plants include: yuccas, ocotillo, turpentine bush, prickly pears, false mesquite, sotol, ephedras, agaves and brittlebush. </li></ul>
  5. 5. What Happens to the Body in Extreme Heat? <ul><li>People suffer heat-related illness when their bodies are unable to compensate and properly cool themselves. The body normally cools itself by sweating. But under some conditions, sweating just isn't enough. In such cases, a person's body temperature rises rapidly. Very high body temperatures may damage the brain or other vital organs. </li></ul><ul><li>Several factors affect the body's ability to cool itself during extremely hot weather. When the humidity is high, sweat will not evaporate as quickly, preventing the body from releasing heat quickly. Other conditions that can limit the ability to regulate temperature include old age, youth (age 0-4), obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug use and alcohol use. </li></ul>
  6. 6. Continued <ul><li>Heat Stroke- Heat stroke occurs when the body is unable to regulate its temperature. The body's temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. Body temperature may rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not provided. Typical symptoms are extremely high body temp., nausea, dizziness, red dry skin(no sweat), throbbing head ache, and confusion </li></ul><ul><li>Heath Exhaustion- Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids. Those most prone to heat exhaustion are elderly people, people with high blood pressure, and people working or exercising in a hot environment. </li></ul>
  7. 7. Continued <ul><li>Heath Cramps- Heat cramps are muscle pains or spasms usually in the abdomen, arms, or legs that may occur in association with strenuous activity. If you have heart problems or are on a low-sodium diet, get medical attention for heat cramps. </li></ul><ul><li>Dehydration- condition caused by the excessive loss of water from the body, which causes a rise in blood sodium levels. Since dehydration is most often caused by excessive sweating, vomiting, or diarrhea, water loss is usually accompanied by a deficiency of electrolytes. If untreated, severe dehydration can lead to shock. </li></ul>
  8. 8. Body Systems Affected <ul><li>The Cardio Vascular System-Blood pressure increases, blood thickens due to the removal of water from dehydration. </li></ul><ul><li>Integumentary System- In extreme heat people are at seriously risk of sunburn. Also if dehydrated skin can become very dry due to nothing to sweat out. </li></ul><ul><li>Muscular System- Lack of water decreases ability of muscles to operate properly, especially since the body extracts water from muscles and other organs when sufficient water isn’t being taken in. </li></ul>
  9. 9. Adaptations <ul><li>The bodies first line of defense is sweat. When the body reaches a certain temperature water is released through millions of tiny pours on your body so they can evaporate and lower your temperature. </li></ul><ul><li>If water from sweat and excretion is not replaced the body draws water from it’s muscles and organs in order to keep running. However this greatly decreases the function of the organs and muscles. </li></ul>

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