Before the Adventure Update, biomes were much smaller and less distinct.
Biome placement was controlled by temperature and rainfall values, allowing interface biomes and making it nearly impossible to generate desert near taiga or rain forest near tundra while making transitions from biome to biome smoother. Height variation was less dependent on biome type, allowing cliffs and mountains to generate up to 128 y-axis in any biome (new versions only allow tall mountains to spawn in Extreme Hills and Savanna Plateau M). Tall grass was also much less present in pre-1.8 worlds (except in the "Plains" and "Rainforest" biomes).
|Rain Forest||Rainforests are very wet biomes with many trees, which have a 1 in 3 chance of being big, instead of 1 in 10 like all other biomes. They only generate oak trees, and have a large amount of tall grass and ferns. A biome is classified as a rainforest if the temperature is greater then 97% and the rainfall is more than 90%. This could be the biome with some of the most cliffs and hills, because the world generator reduces height variation at lower rainfalls.|
|Seasonal Forest||Seasonal Forests spawn with a temperature of 97% or greater, and a rainfall value between 45% and 90%. They are commonly found between forest and rain forests, and near plains biomes. They are identical to forests, except they have less trees and are only capable of spawning oak trees. They have a little bit of tall grass.|
|Forest||A biome with many trees and a little bit of tall grass. Wolves can spawn here. Forest is the only biome where birch trees spawn. It generates when the temperature is between 50% and 97%, and the rainfall is 35% or greater.|
|Swampland||Identical to shrubland with only the unused color variables and the biome name differing. It generates when the temperature is between 50% and 70%, and the rainfall is greater than 40%. Because 50% temperature and below causes snowfall, the swamp biome can have snow (although it will not regenerate and will rain instead of snow). Even though the swamp biome only generates at above 50% temperature, snow can still generate on hills because the higher the altitude, the higher the temperature that snow can spawn in.|
|Savanna||A biome with mostly flat terrain and a few trees, although some hills do spawn. It seems to be one of the flattest biomes in the game, alongside desert and tundra, due to the game reducing height variation at lower rainfall values. The grass color can range from dull orange to blue-ish gray. It generates with a temperature between 50% and 95%, and a rainfall value of less than 20%
|Shrubland||A biome with few trees and no tall grass. It is identical to the savanna biome. It is one of the smallest biomes in the game, and only spawns if the temperature is between 50% and 97%, and the rainfall value is below 35% and therefore too little to generate a forest.|
|Taiga||A snowy biome composed of mostly mountainous terrain and a bit of tall grass. Spruce and pine trees as well as ice can be found in this region. Wolves also appear more commonly on this biome than others. Snow is a common weather in taiga biomes. It generates when the temperature is between 10% and 50% and the rainfall is greater than 20%. In Beta 1.8 and Java Edition 1.0, taiga biomes generated without ice and/or snow due to a bug.|
|Desert||A biome consisting mostly of sand, dead bushes and cacti. Trees do not generate in deserts unless the player brings in dirt. No rain occurs in this biome. It spawns when the rainfall is less than 20% and the temperature is greater than 95%.
Since Beta 1.0 and before Beta 1.4, biome borders were rotated and didn't line up because of a bug, which was more noticeable for deserts due to the fact that they generate different ground blocks than the other biomes.
|Plains||A very flat biome with a very large amount of tall grass (more than in any other type of land). The occasional trees do exist, though very rarely. Plains are typically smaller than other biomes because they have an extremely marginal generation range, only occurring if the temperature is greater than 97% and the rainfall is greater than 45%. Despite having a larger rainfall range than rainforest, the rainfall values fall into this range less often because they sometimes go outside of 0%-100% and are capped at those values, and can become "stuck" at 0% or 100% for some time.|
|Tundra||Snowy, barren terrain with very few trees. The occasional trees do exist, though very rarely. Ice can be found over water. Snow is a common weather in tundras. It generates when the temperature is below 50% and the rainfall is less than 20%.
In Beta 1.8, Notch also said that this biome would be left out until "Beta 1.9". This is because snow was causing problems with the new biome generator.
|Sky||A hidden biome before Beta 1.9 Prerelease 4, this biome was exclusive to, and the sole biome of the Sky Dimension. It would generate floating islands with oceans of air surrounding them. Trees were uncommon. No weather occurred here. It had small patches of snow, although it would not accumulate again. It had green with some extra blue hue for foliage colors.|
|Ice Desert (corner case biome)||An unused biome before Beta 1.8 that was in the code but never implemented into the temperature/rainfall table and thus did not actually generate. It was a biome of sand with snow on top of it and had snowfall and ice.|
|Hills/Cliffs||Mountains are hills with extreme slopes. Prior to the 1.8 update, these highly mountainous landforms were found in all type of biomes, but from the Adventure Update onwards are very rare outside the Extreme Hills and Mesa biomes. They were generated as part of the terrain generation algorithm.
Cliffs are often carved into hills, and sometimes have caves protruding into them. These caves contain the same blocks which one would find at the same layer in the hill they are carved out of.
|Ocean||Oceans are huge bodies of water with every single water tile being a spring. Prior to the Adventure Update, oceans were generated as part of the terrain generation algorithm, but since then they are part of the Ocean biome.|
|Beaches||Beaches are usually generated next to oceans or lakes and covered all nearby low elevated shorelines. They could be found in any biome. They came in two varieties: sand beach and gravel beach. Sandstone was located below sand in sand beaches.
Gravel beaches had no such border and thus posed dangers like falling into caverns located right underneath them.
Due to the changes in the terrain generation algorithm in the Java Edition Beta 1.8 update beaches were removed completely from the game. They later returned with Minecraft Java Edition 1.1 as a separate biome, but were lacking the spaciousness of old beaches from Beta versions ever since, and only came in the sand variety.