Plant adaptations to climate Due to harsh conditions, plants are sparse and small, however, variations in temperature, rainfall, geology and soils can lead to wide differences in species diversity. There are a number of ways in which vegetation in HA and SA areas combat drought:

Ephemerals Def: Plants with a short life cycle which flower after rain and then seed and die. (they escape drought by remaining as seeds until rain falls when they germinate)

Succulents Def: Plants which store water in fleshy stems and leaves e.g. Cacti. Cope by collecting and storing water during seasonal rains to draw upon during dry periods.

To reduce transpiration they close their stoma during the day and open them at night when it is cooler. Many also have thickened, waxy leaves or cuticles which act like waterproofing to reduce water loss. Plants with adaptive mechanisms like this are called xerophytes.

Phreatophytes Obtain water from long roots which extend to groundwater below the water table e.g. Mesquite bush Many have small leaves/spines to reduce transpiration losses Some loose their leaves in the dry but continue to photosynthesise on their green stem e.g. Palo Verde Stomata are more numerous on the underside of the leaf.

Halophytes High evaporation can create salt pans. Plants growing in saline soils are called halophytes e.g. Saltbush excretes salt into its leaves when conditions become too saline.

Harsh conditions make food supply scarce. Many plants e. g Harsh conditions make food supply scarce. Many plants e.g. Prickly Pear cactus have evolved spines to protect themselves Others contain poisonous latex The Creosote bush gives off toxic substances to deter other plants from growing nearby Some plants are parasitic e.g. orobanca

Different HA and SA areas contain different types of vegetation e. g Different HA and SA areas contain different types of vegetation e.g. Australian deserts are dominated by spinifex grass and eucalyptus. The Namib has euphorbia succulents.

Animal adaptations