Three biomes in Minecraft will be updated with new features. Those are deserts, taigas, and savannahs biomes. Biome Chooser Addon is not only added some new mobs such as Meerkats and Ostriches but also stuff like new trees and bushes.
Biome Chooser Addon Feature
Desert Biome in Biome Chooser Addon is called Meerkats which only lives in the desert. It will instantly die if you spawn them in the other biomes that are not desert
You can see the new trees which are a custom model for blocks. These blocks replace the Shulker. They also spawn randomly in the desert or you can use Berry Bush to spawn this biome specific tree.
Foxe replaces Wolves that can be found randomly in Taiga biomes
Here is the Berry Bush which is a biome specific bush. It will also spawn here and can shear them to get berries. It takes 10 minutes to grow this Berry Bush.
Campfire is an entity which can only be spawned by summoning a Zombie Villager
Ostriches are two-legged birds. It replaces Chickens and can be used as rideable mounts
A giant tree is called Baobabs
This is a Termites! It's similar to spiders but smaller and attack trees!
You can get .ZIP file here: Biome Chooser Addon