Early classification 2000 years ago, Aristotle divided all living thing into two large groups Plantae and Animalia Most animals are motile (move) in order to obtain food Most plants are stationary and obtain food through photosynthesis

Micro-organisms The invention of the microscope in the 1600s made classification more difficult Many micro-organisms had characteristics of both plants and animals euglena: has flagellum to propel itself – animal characteristic goes through photosynthesis – plant characteristic

Micro-organisms - Protista Protista - Ernst Haeckel (1866) came up with the 3-rd kingdom ] Protista was the kingdom for micro-organisms that were neither plants nor animals Extremely diverse kingdom (size, habitat, behaviour)

Micro-organisms - Fungi Fungi (mushrooms, mould) were originally in the plant kingdom Fungi are sessile (stationary) and many grow in the ground – plants? No! Fungi are not photosynthetic Different methods of reproducing

Micro-organisms - Bacteria Bacteria are single celled organisms Bacteria lack membrane-bond organelles They are the smallest organisms on Earth Thy are most dominant form of life in every habitat

Micro-organisms - Archea 1990 – Bacteria Kingdom was split into Bacteria and Archaea Archaea cell membranes and walls have a unique chemical makeup (resistant to physical and chemical disruptions) Many inhabit extreme environments (salty, hot, cold, low-oxygen)

classification