SBI3U Diversity of Living Things Chapter 1.notebook February 12, 2012 What are Kingdoms and Domains? There is far too much structural diversity among organisms to compare them all at the species level. For this reason, biologists look at the kingdom and domain levels for similarities and differences. There are two main cell types that classify organisms into three domains. Feb 58:31 PM Prokaryotic cells • do not have membranebound nucleus • most species are unicellular • no species of prokaryotes are multicellular • some live in colonies while others are filamentous Archaea Bacteria Feb 711:10 AM SBI3U Diversity of Living Things Chapter 1.notebook February 12, 2012 Eukaryotic Cells • membranebound nucleus • more complex internal structure • usually larger than prokaryotic cells • Some are unicellular and some are multicellular Feb 711:12 AM The three domains in our current classification system are Bacteria, Archaea, and Eukarya We distinguish among domains in kingdoms through, • cell types number structure • nutrition • reproduction Feb 711:17 AM SBI3U Diversity of Living Things Chapter 1.notebook Domain February 12, 2012 Archaea Bacteria Kingdom Bacteria Archaea Cell Type Prokaryote Prokaryote Number of Cells Unicellular Unicellular Cell Wall Material Peptidoglycan Not peptidoglycan; occasionally no cell wall Nutrition Autotrophs and Heterotrophs Autotrophs and Heterotrophs Primary means of reproduction Asexual Asexual Feb 711:24 AM Eukarya Domain Kingdom Protista Plantae Fungi Animalia Cell Type Eukaryote Eukaryote Eukaryote Eukaryote Eukaryote Number of Unicellular Multicellula Mostly & Multicellu r Multicellula Cells lar r Cell wall Material Cellulose in Cellulose some; occasionally no cell wall Nutrition Autotrophs Autotrophs Heterotrophs Heterotrophs & Heterotrop hs Asexual & Primary means of Sexual reproductio n Sexual Feb 711:30 AM Shitin Sexual No Cell Wall Sexual SBI3U Diversity of Living Things Chapter 1.notebook February 12, 2012 Learning Check: 1. Which kingdom exhibits a prokaryotic cell plan? a. Animalia d. Protista b. Archaea e. Plantae c. Fungi 2. Why does our classification system divide organisms into large, general groups such as domains and kingdoms, as well as specific groups like species? 3. Three new species are discovered. State which domain each species is in and how you know. a. Species A is multicellular b. Species B is unicellular, has no membrane around its nucleus, and has a cell wall composed of peptidoglycan c. Species C is unicellular and has no membrane around its nucleus. Although Species C doesn't have a cell wall, most representatives of its domain have a cell wall that is not composed of peptidoglycan Feb 711:40 AM Using a Dichotomous Key It is easier to consider two options than it is to consider many options at the same time. A dichotomous key allows us to make simple choices, one at a time, to help identify organisms. Dichotomous keys are usually used to help identify a species but can also be used to identify an order, a family, or another rank. Feb 711:46 AM SBI3U Diversity of Living Things Chapter 1.notebook February 12, 2012 To use a dichotomous key, make the first choice, and follow instructions to other choices This dichotomous key will help identify which kingdom an organism is in. 1a. prokaryotic go to 2 1b. eukaryotic go to 3 2a. peptidoglycan in cell wall Bacteria 2b. no peptiglycan in cell wall Arachaea 3a. chitin in cell wall Fungi 3b. no chitin in cell wall go to 4 4a. unicellular Protist 4b. multicellular go to 5 5a. autotroph Plantae 5b. heterotroph Animalia 1. Which traits tell you that an organism is in the Kingdom Plantae? a) prokaryotic, peptidoglycan in cell wall b) eukaryotic, peptidoglycan in cell wall c) eukaryotic, cell wall made of cellulose d) eukaryotic, no chitin in cell wall, multicellular, heterotroph e) eukaryotic, cell wall made of cellulose, multicellular, autotroph 2. Choice 4 tells you that if the organism is unicellular it is a Protist. Bacteria are also unicellular. What are Bacteria not listed as a possibility in choice 4? 3. Why is the choice between autotroph and heterotroph not made first? Feb 88:03 PM This is part of a dichotomous key for species of birch trees. 1a. twigs are fragrant go to 2 1b. twigs are not fragrant go to 3 2a. leaves widest near the middle 2b. leaves are widest near the base Betula alleghaniensis Betula lenta 3a. mature bark is dark brown or 3b. mature bark is white go to 5 gray go to 4 4a. Leaves yellowish green and 4a. leaves dark green and hairy shiny Betula occidentalis Betula kenaica You have found a birch tree and want to identify it. a. what is the first thing you need to do? b. The twigs of the birch tree and not fragrant, and the bark is dark brown. What is the next decision you need to make, and what will that tell you about the tree? Feb 88:19 PM SBI3U Diversity of Living Things Chapter 1.notebook February 12, 2012 Create your own dichotomous key See page 28 of your textbook once you have finished, get another group to test out your dichotomous key Feb 88:27 PM
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