4. The so-called Brush lily, with its characteristic form that
corresponds to its reproduction cycle, is highly toxic,
particularly for cattle. Its scientific name, Boophane haemanthoides,
comes from boos, which means beef and phonos meaning to kill.
The cricket Dictyophorus spumans absorbs the plant toxins that help
protect it from predators. Its black carapace, trimmed with
red and orange, warns predators of its toxic qualities.
© Jean-Michel Battin
It is known that living organisms have evolved throughout the course of Earth's history. The processes of evolution enable animals and plants to adapt progressively to their environment. In this way, animals from cold regions possess fur or thick plumage while animals from hot regions possess close-cropped fur and long legs, to distance their body from ground surface heat. Moreover, vegetation in drylands present characteristics acquired over time that allows them to survive high temperatures and water shortages. To prevent dessication and therefore save water, the vegetation has reduced the number and surface area of leaves, which develop into scales or thorns. The loss of leaves during the hot and dry season also helps to save water.
They orient their leaves towards the shade, develop rounded or padded
forms and stock water in specific organs such as thickened stems (fleshy,
succulent plants, cacti)
and oversized trunks (baobabs).
Such plants optimize water absorbtion by spreading out their roots horizontally over a large area below the plant or by driving their roots deep into groundwater reserves (See diagram).
Only halophytes (salt-tolerant plants) develop in certain soils of the drylands where they contain a high salt content (salinity).
Plants protect themselves from herbivores in two ways:
Depending on the climate and soil type, various groups of plants develop
concurrently to form living communities that are the basis of terrestrial
The phenomenon of desertification limits vegetation cover to a single level.
In drylands, six major types of plant formations are observed:
forms that develop in coastal drylands.
2. the formation of fleshy or succulent plants (cacti, euphorbias, senecios).
3. shrubland steppes with discontinuous cover.
4. herbaceous savannah with open spaces where grasses predominate.
5. the shrub bushland (shrub, mallee, catinga) where plants often possess thorns.
6. dry forests with tall trees that shed leaves during the dry season.
Which plants characterize the arid environment in your region?
Which plants characterize other arid regions?
Are there any similarities in plant type?
Paste photos or pictures of these plants on the wall chart.
Place several of these plants in plastic pots (Only select plants that are abundant in your area). Calculate the quantity of water needed for watering. Do certain plants need more water than others to grow?
Why do you think this is so?
Which tree plays an important economic role in your region?
Describe the tree and all its possible uses.
Identify a tree that you recognize well. Visit it regularly and keep a check on it. If needs be, water it occasionally, add some compost, etc.
Do you see any improvement in the condition of the tree over days, weeks?
Which of the following plants have adapted to aridity over
the course of evolution:
• water lilies