Eating Habits and Reproduction

All organisms are classified into groups, so ... How do these scientist divided all this organisms? They used many characteristics that could help them, like the type of cell and the amount of cells. These groups were still too big, so they used more characteristics. Two of these are the way the organism gets its food and the way the organism reproduces.

How they get their food - Autotrophs or heterotroph?
Discovery:
http://www.discovery.com/tv-shows/other-shows/videos/assignment-discovery-shorts-06-07-07-08-autotrophs-heterotrophs/

Another characteristic is the way the animal reproduces- Sexually or Asexually
Reproduction:

 https://www.youtube.com/watch?v=ELvTgZnTwSI