Re: Which plants do not need sunlight and how do they survive?

Dear Taeko,

Before I can answer your question, I need to define what a plant is.  
Initially, living things were classified into two kingdoms: Plant and 
Animal.  This classification was based on plants having cell walls and 
animals not having cell walls.  Since bacteria and fungi have cell walls, 
scientists used to study them as unique groups of plants.  Today, 
scientists have placed bacteria and fungi into their own kingdoms.  
Bacteria are in the Kingdom Monera.  They are prokaryotic (no cell 
nucleus).  Fungi are in the Kingdom Fungi(no photosynthesis).  
Remaining in the plant kingdom today are eukaryotic (have a cell nucleus) 
organisms that use photosynthesis to survive.  As you may know, some 
plants, like the Venus Fly Trap are photosynthetic and carnivorous.  
However, they cannot sustain themselves just on their carnivorous diet.

Some bacteria do not need sunlight to survive.  They live next to 
hydrothermal vents in the deep sea, far below a depth which sunlight can 
penetrate.  Hydrothermal vents release superheated water with dissolved 
minerals and sulfur into the ocean.  The bacteria use the oxygen and carbon 
dioxide in the seawater along with the sulfur from the vents to produce 
food.  This process is known as chemosynthesis.

Organisms in the Kingdom Fungi are not photosynthetic.  Fungi do 
not need sunlight to survive.  They act as parasites or saprophytes to 
obtain their food.  

If we still considered bacteria and fungi as plants, then we could say that 
there are some plants that do not need sunlight to survive.

Good luck with your science fair!