Adaptation in deserts and osmoregulation evolution

Desertification

The process by which vegetation in drylands, such as grasslands or shrublands, decreases and eventually disappears

2 main causes of desertification

climatic variation and human activities

Climatic variation

Climate change, drought, moisture loss on a global level

Human activities

Include the expansion and intensive use of agricultural lands, poor irrigation practices, deforestation and overgrazing

Drought evaders

exist as seeds before rain comes and grows where it rains. They flower quickly to produce seeds and then die

Drought resistors

perennial plants that possess the abilities of storing water, locating underground or minimising the use of water by various measures

Normal plants

Leaves are photosynthetic, simple stem, basic root system

Desert plants

Leaves evolve into thorns or have a waxy surface, stem succulent and photosynthetic, roots shallow but wide spreading or can be deep

Convergence

Structural similar solutions to the same environmental problems

Camels

Hump contains fat (storage of energy and water). Coat keeps the cooling sweat close to body. Long legs so further from the ground

Honeypot ants

Stay underground, abdomen swells with stored water, fat or honey.

Reflective coloration - white hair or scales in desert animals also help reflect the intense sunlight of the desert

Spiny animals

Desert scorpions are nocturnal and live in burrows or found under rocks

Like many cacti, many lizards also evolved spines as protection from predators

Water conservation

Kangaroo rats are only active at night and stay underground during day

Anhydrobiosis

Extreme dehydration is fatal for most animals. A few aquatic invertebrates live in temporary ponds and can lose almost all their body water and survive. An example of this is tardigrades.

Biomimicry

Biomimicry is a practice that learns from doing and mimics the strategies found in nature to solve human design or engineering challenges