Unit #3 Classification Part 2

Dichotomous Keys Useful tool/chart. We use dichotomous keys to help you identify organisms in the natural world that we don’t know. We can take an organism and identify it by looking at its characteristics. These keys always start with 1A, and 1B. Always start at the top of the key and do what it says. Go to the right and work down.

Dichotomous Keys http://yclifescience2010-2011.wikispaces.com/file/view/Q38rev13.jpg/164647829/Q38rev13.jpg

Evolutionary Classification Phylogeny –the evolutionary relationship among organisms. Scientists now group organisms into categories that represent lines of evolutionary descent or phylogeny, not just physical similarities. This strategy is called evolutionary classification.

Evolutionary Classification: How do scientists decide? Which similarities are most important? Phylogeny Cladograms Similarities in DNA & RNA Molecular Clocks-a model that uses DNA comparisons to estimate the length of time that two species have been evolving independently. Provide clues to evolutionary history.

Cladograms A diagram that shows the evolutionary relationship among a group of organisms Useful tools that help scientists understand how one lineage branched from another in the course of evolution

Cladograms

Cladograms

Cladograms

Cladograms

Cladograms

http://faculty. uca. edu/johnc/phylogenyclad1441 http://faculty.uca.edu/johnc/phylogenyclad1441.htm Derived Characteristics: Characteristics that appear in the recent parts of the lineage

Classification

The Three-Domain System Today we added…. Domain- a large group that is a more inclusive category then any other, even larger than a kingdom. Scientists currently believe this is the most updated system to use. As they make updates, it could change.

Remember: Domains are the broadest level of classification. Archaea and Bacteria contain all prokaryotes which are thought to be the earliest forms of life on Earth. Eukarya contains all eukaryotic organisms .

The Three-Domain System 1. Archaea – Prokaryotes, which corresponds to the Archaebacteria which is old/ancient or gas type bacteria. 2. Bacteria – Prokaryotes, are Eubacteria which is true bacteria. Has 3 common shapes. 3. Eukarya – are Eukaryotes which are composed of protists, fungi, plants, and animals.

6 Kingdoms Eubacteria Archaebacteria Fungi Protista Animalia Plantae NOTE: Viruses are NOT LIVING so they don’t belong in a kingdom

Eubacteria True bacteria Can be round, rod, or spiral shaped Are prokaryotes which are simple cells with no nucleus, no organelles like our cells and just ribosomes and a blob of DNA Have peptidoglycan in their cell walls Largest kingdom of the prokaryotes. This kingdom is bigger than all the other kingdoms put together Are small in size Used to be in the Monera kingdom Examples are E. coli, and blue-green bacteria

Eubacteria

Eubacteria

Archaebacteria Are prokaryotes Are very small Are gases No peptidoglycan in their cell walls The smaller of the bacteria kingdoms Live in very harsh environments Salt lovers and Heat lovers Used to be in the Monera kingdom Ancestors of eukaryotes Examples are the methanogens, halophiles, and thermophiles

Archaebacteria

Fungi Are heterotrophs, have hyphae(tiny filament) Feed on dead or decaying organic matter Secrete digestive enzymes into their food source Are eukaryotes Examples are mushrooms , molds(multicellular), and yeast (unicellular) Used to be in the kingdom Plantae a long time ago

Fungi

Protista Are eukaryotes, we call them protozoans Are not classified as animals, plants, or fungi even though they look like them Have great variety, was a “catch all” kingdom a long time ago Are mostly single-celled, however some are multicellular Some are photosynthetic Can cause disease Examples are amoeba, paramecium, euglena, diatoms, and dinoflagellates

Protista

Animalia Are eukaryotes Are multicellular and heterotrophic Backbones! Invertebrates – 95% to 99% Vertebrates – 1% to 5% Animals can move about for all or part of their life- sponge is sessile (doesn’t move) Incredible diversity Exist in nearly every part of the planet Examples are sponges, insects, worms, jellyfish, crabs, HUMANS,and mammals.

Animalia

Plantae Are eukaryotes Are multicellular Are photosynthetic autotrophs Make sugar (glucose) Put a lot of Oxygen into the atmosphere Are non-motile(not able to move), can grow Have cell walls that contain cellulose Examples: mosses, ferns, flowering plants (angiosperms), some algae, shrubs, and trees

Plantae

Summary of the Six Kingdoms Eubacteria Archaebacteria Protista Fungi Plantae Animalia Cell Type Prokaryote Eukaryote Number of Cells Unicellular Most unicellular; some colonial; some multicellular Most multicellular; some unicellular Multicellular Mode of Nutrition Autotroph or heterotroph Heterotroph Autotroph Examples E.Coli Streptococcus Methanogens, halophiles Amoeba, paramecium slime molds, giant kelp Mushrooms, yeasts Mosses, ferns, flowering plants Sponges, worms, insects, fishes, mammals

Comparison of the Six Kingdoms Factors Archaebacteria Eubacteria Protista Fungi Plantae Animalia Representative Organism (examples)   Cell Type (eukaryotic or prokaryotic) Presence and Type of Cell Wall Macrostructure (unicellular or multicellular) Nutrition (autotrophic or heterotrophic) Locomotion (mobile or immobile) Reproduction (asexual, sexual, or both) Ecological/Economic Importance

Let’s Review: Fungi used to be in Plantae Kingdom Protista was included in the 3 kingdom system a long time ago Cladistic analysis focuses on the order in which derived characters appear in organisms. All organisms have DNA and/or RNA to pass on information

Review: First term is the genus and is capitalized Second term is the specie and is lower case We have only classified a fraction of the organisms on Earth We mostly use Latin to classify or say they are Lantinized To study organisms requires the use of both large and small categories

Review: Bacteria used to be in the kingdom Monera There are 7 levels of classification The main idea behind molecular clocks is that neutral mutations accumulate at a steady rate Our classification system is numerous and diverse

Review: Before Linnaeus, classification was very long and hard to understand Protists are very diverse and cannot fit into any other kingdom We italicize scientific names and some people under-line For many species there are regional differences in the common names of organisms

Review: Organisms that are not closely related but look similar have convergent evolution Organisms with cell walls of chitin are in the kingdom Fungi Our scientific names today are much shorter than in the past

Comparison of the Six Kingdoms Factors Archaebacteria Eubacteria Protista Fungi Plantae Animalia Representative Organism (examples) extremeophiles Cell Type (eukaryotic or prokaryotic) prokaryotic Presence and Type of Cell Wall Cell wall present, made of lipids Macrostructure (unicellular or multicellular) unicellular Nutrition (autotrophic or heterotrophic) autotrophic (chemosynthesis)   Locomotion (mobile or immobile) mobile and immobile Reproduction (asexual, sexual, or both) asexual only Ecological/Economic Importance basis of many food chains (where they could not otherwise be)