Like after many apocalypses, the world did not truly end.

In the thousands of years after the climates and biomes settled, the organisms of Earth faced severe evolutionary pressures to change to fit their new situations. The challenging new environment forced life to struggle to survive, of course, but the lack of much of Earth’s former diversity provided opportunities for those who could seize them. Between the dangerous conditions and the potential for diversification, evolutionary change occurred rapidly.

Thousands of years went by, consisting of generations further and further removed from their ancestors, until those thousands of years became millions. Now, a mere moment in geological time later, the damaged world has finally found comfort in the disaster’s wake. Some organisms look mostly the same, having already been prepared for their new lives. Others are much changed, but can still be roughly identified by the name of their ancestors. Finally, a small portion of organisms have used the elapsed time to the fullest, and have assumed forms unthinkable from those from which they derived. 

POLAR/MONTANE — 

Ice cap: These consist of areas that are covered in ice or snow for more than half of the year. Though some of these areas are tundras in the summer, most are unforgiving environments with nothing to see but packed ice. The vast majority of this biome occurs in the utterly massive North and South Ice Caps. It also occurs as smaller sheets on mountain ranges.

Tundra: Tundras are cold for virtually any tree to grow but are above freezing for most of the year. Vegetation primarily includes sedges, grasses, mosses, lichens, and dwarf shrubs. They occur in polar and alpine regions, and because cold, dry conditions abound, they cover much more area than before. 

Taiga (also boreal forest): Hardy needle-bearing evergreens dominate these lands. The soil is poor due to the cold, but the ground cover includes moss, lichens, grass, and ferns. Unlike the other two polar biomes, permafrost may be absent, and also unlike them, they have not increased in area much, as reduced rainfall worldwide favors tundras and cold deserts. 

TEMPERATE — 

Temperate coniferous forest: With warm summers and cold winters, these have much more varied ground cover than taigas. Broadleaf evergreens and coniferous trees grow in varying proportions.

Broadleaf and mixed forest: Warm and rather wet with a possible dry season, these forests are composed primarily of broadleaf trees. Large trees form a distinct canopy, followed by a multi-layered understory of smaller trees, a layer of shrubs, and finally a diverse ground cover.

Temperate grasslands and shrublands: These sport warm temperatures with rainfall ranging from semi-humid to semi-arid. As the name suggests, nearly all the plants are grass and shrubs with few trees, if any. This biome goes by many names, such as prairie, pampa, steppe, and veldt. In the cold, dry climate, grasslands now dominate much of the unfrozen terrain, forcing the other two temperate biomes into smaller areas. 

TROPICAL —

Tropical rainforests: Wet and warm year-round. Extinct.

Monsoon forests: Subject to the monsoon cycle, these are wet and warm in the wet season, but dry and cooler in the dry season. Extinct.

Tropical dry broadleaf forests: Even dryer than monsoon forests, with severe dry seasons. Extinct.

Tropical grasslands and shrublands: Warm with precipitation between that of a desert and that of the tropical forests. Extinct. 

SUBTROPICAL — 

These biomes are much more similar to their temperate counterparts than their tropical ones. This is even more pronounced on the cold Earth, where subtropical biomes occur in temperatures lower than they typically did in the past. Like temperate biomes, freezing is expected each winter.

Subtropical rainforests: Temperatures here are warm in the summer and warm to cool in the winter. Plant life is markedly diverse with complex layering from canopy to undercover. Summer days are not very much hotter than winter days, but winter nights are much colder, often going below freezing.

Subtropical dry broadleaf forests: These sport wet and warm summers, with winters that function just as much as a dry season as a cold spell. Vegetation is varied, though not so much as in the subtropical rainforests.

Subtropical grasslands and shrublands: Very similar to temperate grasslands and shrublands, though hotter on average and with a less pronounced winter. They are by far the most common subtropical biome now.

DRY — 

Mediterranean forests, woodlands, and scrub: These areas are relatively warm overall, with dry, warm summers and cool, wet winters. The plant life is usually grass and shrubs with the occasional tree. Though named after the Mediterranean coast, it now occurs mostly around the new Indonesian Strait.

Hot deserts and arid shrublands: Very hot summers with only slightly cooler winters. Just as infamously on the old Earth as now, temperatures will drop greatly at night. Back then, however, hot deserts were more common. Now, cold deserts dominate.

Cold deserts and arid shrublands: Contains the bulk of the deserts, and thus have considerable variety. Some are hot in the summer but have cold winters, while others are relatively cool in the summer and have very cold winters. 

WET — 

Wetland: Wetlands have poorly oxygenated soil and are so flooded that terrestrial and aquatic flora live side-by-side. They can exist in nearly any biome, but are found especially often in tundras and taigas the world over.

Mangrove: Characterized by salt-tolerant trees that aid the deposition of water-borne sediment, these grow in brackish or even hypersaline water. Like the wetlands, the soil has very little oxygen. Unlike them, mangroves just barely survived the extinction, hugging the equator for dear life. 

AQUATIC — 

Rivers and lakes: Salt lakes are more common than they once were, as the lower sea level left saline basins behind. Rivers and lakes restricted their inhabitants from moving great distances, so when the cold came, many of these bodies of water were left empty for others to occupy.

Kelp forests: These occur mostly in temperate waters, though occasionally in polar, and, rarely, tropical. Requiring a hard substrate, plenty of nutrients, and sufficiently bright light, they grow in shallow water where nutrient upwelling is present. Through their tolerance of cold water, kelp forests survived the extinction rather well.

Coral reefs: Colonies of coral polyps that harbor much biodiversity. Extinct.

Neritic zone: This is the term for the layer of ocean atop a continental shelf. The water is relatively shallow, allowing light to illuminate the whole depth, usually as far down as the seafloor. The vast majority of sea life lives here. Though the receding oceans turned much of what was once the neritic zone into dry land, it also brought areas of deeper seafloor into the neritic zone.

Pelagic zone: This is the expanse of open ocean away from the continental shelf. It actually consists of multiple biomes stacked atop each other from the surface to the seafloor, but for simplicity’s sake is called by one name to contrast them with the neritic zone. With the land and the neritic zone encroaching, the pelagic zone is smaller than it has ever been before, though it still makes up the majority of the planet’s unfrozen area.

Midnight zone: The oceans here are trapped under the North and South caps, starved of light and subjected to intense pressure. These are not pictured, as they occur only under the caps and at the bottom of the sea.