How do scientists organize organisms? Part IA: In what domain do I belong? Scientists sort life forms into categories based on their characteristics. First, scientists look at the types of cells an organism has to identify whether the organism is a prokaryote or a eukaryote. Cells in a prokaryote: Lack a nucleus Lack a membrane Cells in a eukaryote: Have a nucleus Have a membrane that encloses complex structures, including the nucleus Scientists also look at whether an organism likes living in an extreme environment. An extreme environment might mean an extremely hot place, a very acidic one, or a very alkaline one, for example. Considering this additional characteristic, scientists sort organisms into the three largest categories, called Domains. The three domains are: Archaea a prokaryote; many thrive in extreme environments Bacteria a prokaryote that cannot live in extreme environments Eukarya any eukaryote Using the definitions above, cut out the cards on the next page and paste them on pages 1 and 2 of your Student Journal in the correct Domain.
STUDENT GUIDE 6.12CD: Classification of Organisms 1 2 3 acidic environment 4 5 6 7 8 9 or asexual 10 11 12 very hot environment
How do scientists organize organisms? Part IB: In what kingdom do I belong? Scientists sort organisms into smaller categories than Domains, called Kingdoms. The six Kingdoms are: Eubacteria, Archaea, Protista, Fungi, Plantae, and Animalia. CELL COMPOSITION Unicellular composed of a single cell Multicellular composed of multiple cells EATING Autotrophic makes own food Heterotrophic eats other organisms REPRODUCTION Asexual offspring arise from a single parent Sexual offspring arise from the mating of two parents ABILITY TO MOVE Yes can move around on its own (also referred to as motile ) No cannot move around on its own (also referred to as sessile ) Cut out the cards on the next page. To decide on which kingdom an organism belongs, consider the definitions above, what you learned in Part IA, and your own knowledge about whether the organism has the ability to move or not. Sort and paste the organisms into the correct kingdoms on pages 3 and 4 of your Student Journal.
STUDENT GUIDE 6.12CD: Classification of Organisms 1 2 3 acidic environment 4 5 6 mulitcellular 7 8 9 or asexual 10 11 12 very hot environment
Reflections and Conclusions Write the answers to the questions for this section in your Student Journal. Use a separate, blank sheet of paper, if you need more room to write out your answers or draw illustrations to support your answers. 1. Review the definitions on page 1 of this Student Guide to help you describe the difference between the two categories. Also, look at the organisms you sorted into domains to identify one of each type. 2. Review the cards for the organisms that you sorted into the Animalia and Eubacteria kingdoms. Compare and contrast the lists of characteristics to find two characteristics organisms in both kingdoms share. 3. During this activity, you learned about how scientists examine differentiating characteristics in organisms. To help you answer this question, think about two or three different kinds of plants with which you are familiar. List the characteristics for each one. Analyze what characteristics the different plants have in common and where they seem to differ. Could scientists apply what you discovered in your analysis to help them classify different kinds of plants?