Classification Notes Classification Putting organisms into groups based
Classification Notes
Classification • Putting organisms into groups based on their similarities • How? – Using comparative anatomy. When comparing the anatomies of different organisms, researchers look at 1) Homologous structures 2) Analogous structures 3) Vestigial structures/organs
Patterns of Evolution for classification purposes A) Coevolution = change of two or more species in response to one another • Ex: plant flower shape and pollinator evolve to continue mutualistic relationship • Some Central American Acacia plant species have hollow thorns and pores at the bases of their leaves that secrete. These hollow thorns are the exclusive nest-site of some species of ants that drink the nectar. But the ants are not just taking advantage of the plant — they also defend their acacia plant against herbivores.
Patterns of Evolution B) Convergent Evolution = organisms with different ancestors become very similar due to environment (Ex: sharks and dolphins) C) Divergent Evolution = two or more related populations/species become different (Ex: Darwin’s finches)
Divergent Evolution Convergent Evolution
Patterns of Evolution D) Adaptive Radiation = an extreme form of divergent evolution where many related species evolve from a single ancestor species
Classification • Putting organisms into groups based on their similarities • How? – Using comparative anatomy. When comparing the anatomies of different organisms, researchers look at 1) Homologous structures 2) Analogous structures 3) Vestigial structures/organs
Review of Comparative Anatomy • Homologous Structures = common ancestor; different environments + functions • Analogous structures = different ancestors; same environments + functions • Vestigial structures = organs that were useful in an ancestor, but are no longer useful
Taxonomy • The science of classifying organisms is called taxonomy • First scientist to use modern system of taxonomy = Carolus Linnaeus • He is called the Father of Modern Taxonomy
Linnaeus’s System • Linnaeus developed a naming system using the following: 1) levels of relatedness 2) Based groupings on morphological (STRUCTURAL) differences of organisms 3) Divided organisms into two groups: Animalia and Plantae
Modern Classification • Today, scientists use Linnaeus’s system – the binomial system of nomenclature. Nomenclature = NAMING (putting organisms into named groups!) • This system is based on a ranking system or heirarchy
Modern Classification • Again, the modern system is called the binomial system (bi = two ; nom = name) • This system gives each organism 2 names (bi = two ; nom = name) • These names include the genus and the species
Binomial Nomenclature When writing the scientific name of an organism, both words must be underlined or italicized. The genus is always capitalized, and the species always begins with a lower case letter. • Homo sapiens = human beings • Felis domesticus = domestic cat
Binomial Nomenclature • Scientific names are always written in Latin or Ancient Greek so that they have the same name everywhere! • Can abbreviate the genus with one letter (ex: H. sapiens) • Genus = a group of similar species • How did we define a species in our evolution notes?
Binomial Nomenclature • Scientific names may describe the organism (Ex: Chaos chaos) • They may also honor a person or suggest the habitat of the organism ((Linnaea borealis)
Linnaeus’s Levels • Taxon is a category into which SIMILAR organisms are placed. • The hierarchy which is used today consists of SEVEN groups, going from broadest to most specific • The largest group is the kingdom, and the smallest group is the species
Linnaeus’s Levels • Another way of looking at the levels Memory Trick: King Phillip Came Over For Good Spaghetti
3 Domain System • Carl Woese: compared sequences of ribosomal RNA (r. RNA) 3 broad domains • Domain: Broadest, most inclusive taxon 1) Domain Archaea (Kingdom Archaebacteria) 2) Domain Bacteria (Kingdom Eubacteria) 3) Domain Eukarya (Kingdoms Protista, Fungi, Plantae, and Animalia)
The Six Kingdoms Used to be FIVE kingdoms…the two bacteria types were combined under one kingdom (Monera)
Kingdom Archaebacteria • # of Cells: Unicellular (add) • Cell Type: Prokaryotic (add) • Nutrition: Autotrophs OR Heterotrophs (add) • Cell Wall (add) • Examples: Live in very extreme environments 1) Thermophiles (heatloving) 2) Halophiles (saltloving) 3) Acidophiles (acidloving)
Kingdom Eubacteria • # of Cells: Unicellular (add) • Cell Type: Prokaryotic (add) • Nutrition: Autotrophs OR Heterotrophs * • Cell Wall made with peptidoglycan (add) • Some may cause diseases • Are both aerobic and anaerobic • Important decomposers for ecosystems • Examples: “true bacteria”; most bacteria we know of…live in oxygen-rich environments 1) Streptococcus 2) Staphylococcus 3) E. coli
Kingdom Protista • # of Cells: Unicellular (some multicellular!) (add) • Cell Type: Eukaryotic (add) • Nutrition: Autotrophs and Heterotrophs • No cell wall, membrane only (add) • Most are animal-like • Some are plant-like • Examples: 1) Amoeba 2) Euglena 3) Kelp
Kingdom Fungi • # of Cells: Multicellular, except yeast • Cell Type: Eukaryotic (add) • Nutrition: Absorptive Heterotrophs • Cell Walls made of chitin (“kitein”) (add) • Examples: 1) Mushrooms 2) Puffballs 3) Mildews 4) Molds 5) Yeasts (unicellular)
Kingdom Plantae • # of Cells: Multicellular • Cell Type: Eukaryotic (add) • Nutrition: Autotrophs (Photosynthesis) • Cell wall made of Cellulose • Examples: 1) mosses 2) evergreens 3) flowering plants (ex: daisies) • So are carnivorous plants like the venus fly trap autotrophs?
Kingdom Animalia • • • # of Cells: Multicellular Cell Type: Eukaryotic Nutrition: Heterotrophs (ingestion) No cell wall, membrane only (add) Examples: 1) Jellyfish 2) Insects 3) Amphibians 4) Sponges
Foldable Instructions • Front: 6 flaps, one for each kingdom name • Inside on left, 2 example organisms in that kingdom and sketch them (ex: Amoeba for Protista or Moss for Plantae) • Inside on Right: – Cell Type: Prokaryote or Eukaryote? – Body Form: Unicellular or Multicellular? – Cell Boundary: Cell Wall made of ____, membrane only, etc. – Metabolism: Autotroph or Heterotroph (be specific)
• How does a virus work? • Single Celled Organisms – prokaryotes and protists • Comparing Bacteria • Protists and More Protists • Fungi and more fungi • Plants • Animal phyla
Cladograms • Cladograms help scientists understand how one lineage branched from another in the course of evolution. • Organism on left that “branched off” first is the least like the other organisms (it shares the least amount of characteristics) • The two on the right are MOST CLOSELY related (they diverged relatively recently and share many of the characteristics)
Dichotomous Key • A dichotomous key is a tool that allows the user to identify items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. • "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give characteristic choices in pairs.
Hints: Use constant characteristics rather than variable ones Use measurements rather than terms like "large" and "small”. Make the choice a positive one - something "is" instead of "is not”. Finish the dichotomous key with a name of the organism
1. a. wings covered by an exoskeleton – go to step 2 b. wings freely observed – Go to step 3 2. a. body has a round shape ………. b. body has an elongated shape ………. 3. a. wings point out from the side of the body ………. b. wings point to the posterior of the body ……….
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