Photosynthesis is the process by which trees and all other flora (plants) get energy. And I think that it directly helps animals, such as ostriches, by providing food and O2 (oxygen). Without oxygen, humans and animals couldn't survive because there is too much CO2 (carbon dioxide) in the air (humans get this thing called carbon dioxide poisoning, which can kill you eventually). Also, without food, we would all starve to death.
Hope this helps! :)
