Classifying Life http://www.youtube.com/watch?v=F38BmgPcZ_I&safe=active

Why do biologists classify organisms? Biologists use classification to organize living things into groups so that they are easier to study. What are the levels of classification? A domain is the largest level of organization. Within a domain there are kingdoms. Within kingdoms, there are phyla. Within phyla are classes. Within classes are orders. Within orders are families. Each family contains one or more genus. Finally, each genus contains one or more species.

How are taxonomic keys useful? Taxonomic keys are useful tools that help determine the identity of organisms. How are organisms classified into domains & kingdoms? Organisms are placed into domains & kingdoms based on: cell type ability to make food number of cells in their bodies

3 Domains of Life Domain Archea (bacteria) Been on Earth for 3 billion years Thrive in harsh environments such as: hot springs and hydrothermal vents Autotrophs – using chemosynthesis Heterotrophs Differ chemically from Eubacteria and in cell structure. Domain Bacteria (bacteria) Eubacteria which include most bacteria Found nearly everywhere

Domain Eukarya Organisms in this domain have eukaryotic cells. Eukaryotes are organisms with cells that contain nuclei. There are 4 kingdoms within this domain

Kingdom Protista Single celled or simple multicellular organisms Eukaryotic cells Evolved 2 billion years ago and are made up of all eukaryotes that are not plants, animals or fungi. Can be animal-like, plant-like or fungus-like in their characteristics

Kingdom Plantae Usually green and can utilize the process of photosynthesis making them autotrophic Complex, multicellular organisms

Kingdom Fungi Originally classified as plants, but do not do photosynthesis so eventually were placed in their own kingdom Includes molds and mushrooms Can be unicellular or multicellular Heterotrophs

Kingdom Animalia Complex, multicellular organisms Most can move and have nervous systems that help them sense and react to their surroundings Cells lack cell walls unlike plants, fungi, bacteria, and most protists Heterotrophs