Presentation on theme: "How do Scientists Classify Organisms? Chapter 7 lesson 1."— Presentation transcript:
How do Scientists Classify Organisms? Chapter 7 lesson 1
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.
Bacteria Bacteria 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 eubacteria Archaebacteria are the oldest known organisms
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.
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.