Presentation on theme: "How do Scientists Classify Organisms?"— Presentation transcript:
1 How do Scientists Classify Organisms? Chapter 7 lesson 1
2 Kingdoms of Living Things Biologists use a scientific system that organizes living things into groups.Organisms are classified according to internal and external characteristics.(Would a turtle and a dog be classified together?)Scientists use dichotomous keys to help identify organisms.
3 BacteriaBacteria are among the smallest of organisms and are the most numerous.Bacteria are single-celled and do not have a nucleus.Bacteria are divided into two kingdoms: archaebacteria and eubacteriaArchaebacteria are the oldest known organisms
5 Protists Most protists are single-celled All protist cells have a nucleus.Animal like protists are called protozoa.Algae are an example of plant like protists.Many Fungi-like protists have harmful effects on plants and animals.
6 FUNGI Fungi can be single-celled or multicellular organisms All fungal cells have a nucleus.Fungi cell walls are made of the same substance that forms insect shells. (Think of a roach when you step on it.)Fungi absorb nutrients from their environment by decomposing organic tissue.