Kingdoms and Domains Biology 112

Outcomes:  The student will be expected to:  Develop a list of characteristics shared by living things  Identify the general characteristics that distinguish the members of each recognized kingdom  Demonstrate an understanding that the recognized kingdoms of living things represent a diversity of organisms exhibiting extensive variety in terms of form and function

Characteristics of Living Things  No single characteristic is enough to describe a living thing  Some nonliving things share characteristics with living things  All living things:  Made up of units called cells  Reproduce  Are based on a universal genetic code  Grow and develop  Obtain and use materials and energy  Respond to their environment  Maintain a stable internal environment  Taken a group, change over time

The Six Kingdoms of Life  Prokaryotes  Used to be called Kingdom Monera  Eubacteria and Archaebacteria  Lack nuclei, mitochondria, and chloroplasts as well as reproduce by binary fission  Been evolving for 3.5 billion years  Eukaryotes  Protista, Fungi, Plantae, and Animalia  Been evolving for 2.0 billion years

The Three Domain System  Scientists have grouped organisms based on how long they have been evolving independently  As a result, the domain has been introduced as being even more inclusive (larger and sharing less characteristics) than the kingdom  Domain Eukarya  Domain Bacteria  Domain Archaea

Domain Bacteria  Unicellular and prokaryotic  Cells have thick walls that surround the membrane made of peptidoglycan  They may photosynthesize and some require oxygen  Examples include Streptococcus, salmonella, E. coli

Domain Archaea  Unicellular and prokaryotic  Many can only survive in the absence of oxygen  Their cell walls lack peptidoglycan but membranes contain a lipid that are not found in any other organism  Example: Thermococcus litoralis

Domain Eukarya  Consists of the four remaining kingdoms  Protista – displays the greatest variety among its members  Fungi – heterotrophs; most found on dead and decaying matter  Plantae – multicellular and photosynthetic, non-motile, cell walls contain cellulose (when they are present)  Animalia – multicellular and heterotrophic, no cell walls