unit 5: the diversity of life
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Unit 5: The Diversity of Life
Chapter 22: Systematics (Classification)
Systematics
The scientific study of the diversity of organisms and their evolutionary relationships Taxonomy – the science of naming,
describing, and classifying organisms Classification – arranging organisms into
groups based on their similarities, which reflect historical relationships among lineages
Binomial Nomenclature
Carolus Linnaeus simplified the complicated, older system of classification
Binomial System of Nomenclature Makes classification an
international science Each species assigned a
two-part name
How to Write Scientific Names
1. First part of a scientific name = genus
2. Second part of scientific name = specific epithet
3. Genus name is always capitalized.
4. Specific epithet is not capitalized.
5. Scientific names are typed in italics
6. Scientific names are underlined (separately) if handwritten
7. Ex. Scientific name for dog
Canis familiaris or Canis familiaris
Taxonomic Levels
Domain Kingdom Phylum Class Order Family Genus Species
*A taxon is a formal grouping of organisms at a specific level, such as the genus.
Domains and Kingdoms
3 Domains: Archaea
Kingdom Archaebacteria Eubacteria
Kingdom Eubacteria Eukarya
Kingdom Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia
Kingdom Archaebacteria
Prokaryotes Unicellular Microscopic Peptidoglycan absent in cell walls Differ biochemically from eubacteria Ecological Role:
Live in extreme environments: Methanogens – sewage, swamps Halophiles – salty environments Thermophiles – hot, acidic environments
Kingdom Eubacteria
Prokaryotes Unicellular Microscopic Cell walls composed of peptidoglycan Ecological Role:
Most are decomposers Some chemosynthetic Some photosynthetic Important in recycling nitrogen
Kingdom Protista
Eukaryotes Mainly unicellular or simple multicellular 3 informal groups:
Protozoa Algae Slime Molds/Water Molds
Ecological Role: Protozoa - Zooplankton Algae - Important producers Important oxygen source
Animal-Like Protists: Protozoans
Plantlike Protists: Unicellular Algae
Plantlike Protists: Red, Brown, & Green Algae
Kingdom Fungi
Eukaryotes Heterotrophic Absorb nutrients Cell walls of chitin Body composed of threadlike hyphae that form tangled
masses that infiltrate food Ecological Role:
Decomposers Some parasitic Used as food Yeast – bread and alcohol Drugs – antibiotics Spoilage, Crop loss
Sac Fungi
Club Fungi
Symbiotic Relationships
Lichens – symbiotic relationship between fungus and photosynthetic organism Pioneer species
Kingdom Plantae
Eukaryotes Multicellular Photosynthetic Multicellular reproductive organs Alternation of generations Cell walls of cellulose Ecological Role:
Primary producers Source of oxygen in atmosphere
Types of Plants
The Animal Kingdom
Which of these is an animal?
Kingdom Animalia
Eukaryotes Multicellular heterotrophs Complex organ systems Ability to move Specialized nervous tissue Ecological Role:
Consumers Herbivores, carnivores, or detritus feeders
Amazing Fact!
95% of animals are invertebrates Only 5% of animals are vertebrates
7 Essential Functions of Animals
1. Feeding
2. Respiration
3. Circulation
4. Excretion
5. Response
6. Movement
7. Reproduction
Phyla of Animals
Porifera - sponges Cnidaria – jellyfish, sea anemone Platyhelminthes – flatworms Nematoda – roundworms Annelida – segmented worms Mollusca – mollusks: octopus, snail, clam, oyster Arthropoda – scorpions, crab, all insects Echinodermata – sea stars, sea urchins Chordata – fish, reptiles mammals, amphibians,
birds
Your Assignment
Research 10 different organisms and record their classification levels Domain Species Name (genus and specific
epithet) 9 must be from the different phyla of animals,
the 10th can be from any other kingdom. Due tomorrow!
Phylogeny
Goal of systematics is to determine phylogeny – evolutionary relationships Homology – implies evolution from a common
ancestor Shared ancestral characters – suggest a distant
common ancestor Shared derived characters – indicate a more recent
common ancestor Molecular systematics – compares DNA for
assessing evolutionary relationships
Cladograms
Diagrams that illustrate phylogeny Base of cladogram – common ancestor for all
taxa being analyzed Branch point (node) – immediate common
ancestor of the next group Example cladograms p.480
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