Tropical deserts

Where found- South America along Pacific Coast, Sahara and Namibia in Africa, and Central Australia (slide map of tropical deserts from text, Fig 2.1), other slides of desert maps

Why do they occur- low, variable rainfall -high pressure cells and rain shadows (slide text figure 2.2, slide Figure 2.3 equivalent).

What are their conditions (slide Figure 1.12 equivalent)

rain-less than 250 mm per year (Table 2.1 from text)

temperature – large ranges, daily, annual

Types of tropical deserts

Africa as a case study – Figure of Africa vegetation (many are available on web), Figure of African vegetation from space

Figure of Africa climate diagrams (shown previously).

Australian desert (Australian desert climate diagram)

Challenges to desert organisms

Species adaptations to desert environment (Table 2.2 from text)

Species strategies to desert environment (Table 2.3 from text)

Physiognomy (pictures of various tropical deserts)

Productivity- it is all about the water Figure 2.11, Table 3.3 from text, other tables shown previously about global productivity)

Soils and nutrients

Diversity endemics

Desertification shifting deserts and human caused changes (Figure similar to Fig 4.3 but over thousands of years)