Tundra
The tundra is the simplest biome in terms of species composition and food chains, which may have only formed within the last 10,000 years. The word "tundra" comes from the Finnish word tunturi, meaning "treeless plain".
Types
Arctic tundra
Alpine tundra
?Antarctic tundra: there are similarities between cold deserts and tundra
Climate
6 to 10 week growing season; long, cold, dark winters
Rainfall
On average, 15 to 25 cm/yr, but some may get more precipitation
Temperature
Extremely cold climate
Average annual is below 0°C
Average winter temperature is -34° C (-30° F)
Average summer temperature is 3-12° C (37-54° F)
Soil
No true soil; permanently frozen subsoil, permafrost, consisting of gravel and finer material
Limitation of drainage
Flora
Low biotic diversity
Antarctica consists of 2 angiosperm spp.; ~100 spp of mosses; ~30 spp of liverwort
Antarctic hair grass (Deschamsia antarctica) and Antarctic pearlwort (Colobanthus quitensis) are the only native plant species found on the continent.
Short season of growth and reproduction
Ground-hugging forms; mats/cushions; rosettes
Regional Expressions
High latitudes of the northern hemisphere in a belt around the Arctic Ocean
Evolution of the biome
The tundra, a biome that is cold and low in productivity may have only formed within the last 5 million years
During much of the Mesozoic, the Earth was warmer, even at and above Arctic Circle, therefore conditions didn't exist to create tundra
It is possible that a cold and low productive environment dominated by bryophytes and lichens may have existed in previous geological times
Additional Resources
Rain Comes to the Arctic, With a Cascade of Troubling Changes (YaleEnvironment 360, 20Feb2024)
The Flora of Antarctica: Life on a Frozen Continent (In Defense of Plants, Nov 2019)