Autotrophs are the food chain creators, which means they produce their own nutrients and energy through a process known as photosynthesis. They comprise algae, plants, and also some bacteria and fungi.
Cyanobacteria (blue-green algae) are a type of prokaryotic, autotrophic bacterium that contains photosynthetic pigments (chlorophyll and phycocyanin).
Dogs, fungi & tigers are heterotrophic organisms. They cannot prepare their own food and hence depend on other organisms for food.