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Chapter 18 Lecture- Classification
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Chapter 18 Lecture- Classification

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Chapter 18 lecture for Lab Biology

Chapter 18 lecture for Lab Biology

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  • 1.  
  • 2. 18-1 Finding Order in Diversity
  • 3. 18-1 Finding Order in Diversity
    • Natural selection and other processes have led to a staggering diversity of organisms.
    • Biologists have identified and named about 1.5 million species so far.
    • They estimate that 2–100 million additional species have yet to be discovered.
  • 4.
      • To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner.
  • 5.
      • In the discipline of taxonomy , scientists classify organisms and assign each organism a universally accepted name.
      • When taxonomists classify organisms, they organize them into groups that have biological significance.
  • 6.
    • Assigning Scientific Names
        • Common names of organisms vary, so scientists assign one name for each species.
        • Because 18 th century scientists understood Latin and Greek, they used those languages for scientific names.
        • This practice is still followed in naming new species.
  • 7.
      • Early Efforts at Naming Organisms
        • The first attempts at standard scientific names described the physical characteristics of a species in great detail.
        • These names were not standardized because different scientists described different characteristics.
  • 8.
      • Carolus Linneaus developed a naming system called binomial nomenclature .
      • In binomial nomenclature , each species is assigned a two-part scientific name.
      • The scientific name is italicized.
  • 9.
    • The first part of the name is the genus name (Capitalized).
    • A genus is a group of closely related species.
    • The second part of the name is the species name (lowercase).
    • The species name often describes an important trait or where the organism lives.
  • 10.
    • Linnaeus's System of Classification
    • Linnaeus not only named species, he also grouped them into categories.
  • 11.
    •  
        • Linnaeus’s seven levels of classification are—from smallest to largest—
          • species
          • genus
          • family
          • order
          • class
          • phylum
          • kingdom
  • 12.
    • Each level is called a taxon , or taxonomic category.
    • Species and genus are the two smallest categories.
    Grizzly bear Black bear
  • 13.
    • Genera that share many characteristics are grouped in a larger category, the family .
    Grizzly bear Black bear Giant panda
  • 14.
    • An order is a broad category composed of similar families.
    Red fox Grizzly bear Black bear Giant panda
  • 15.
    • The next larger category, the class, is composed of similar orders.
    Abert squirrel Class Mammalia Black bear Giant panda Grizzly bear Red fox
  • 16.
    • Several different classes make up a phylum .
    PHYLUM Chordata Black bear Giant panda Grizzly bear Red fox Abert squirrel Coral snake
  • 17.
    • The kingdom is the largest and most inclusive of Linnaeus's taxonomic categories.
    KINGDOM Animalia Black bear Giant panda Grizzly bear Red fox Sea star Abert squirrel Coral snake
  • 18. Red fox Grizzly bear Black bear Giant panda Sea star Coral snake Abert squirrel
  • 19. 18-2 Modern Evolutionary Classification
  • 20.
      • Linnaeus grouped species into larger taxa mainly according to visible similarities and differences.
  • 21.
    • Evolutionary Classification
        • Phylogeny is the study of evolutionary relationships among organisms.
  • 22.
      • Biologists currently group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities.
      • Grouping organisms based on evolutionary history is called evolutionary classification.
  • 23.
    • The higher the level of the taxon, the further back in time is the common ancestor of all the organisms in the taxon.
    • Organisms that appear very similar may not share a recent common ancestor.
  • 24.
        • Different Methods of Classification
    Appendages Conical Shells Crustaceans Mollusk Crab Barnacle Limpet Crab Barnacle Limpet Molted external skeleton CLASSIFICATION BASED ON VISIBLE SIMILARITY CLADOGRAM Segmentation Tiny free-swimming larva Active Art
  • 25.
    • Superficial similarities once led barnacles and limpets to be grouped together.
    Appendages Conical Shells Crab Barnacle Limpet
  • 26.
    • However, barnacles and crabs share an evolutionary ancestor that is more recent than the ancestor that barnacles and limpets share.
    • Barnacles and crabs are classified as crustaceans, and limpets are mollusks.
  • 27.
    • Many biologists now use a method called cladistic analysis.
        • Cladistic analysis considers only new characteristics that arise as lineages evolve ( called derived characters).
        • Characteristics that appear in recent parts of a lineage but not in its older members are called derived characters .
  • 28.
    • Derived characters can be used to construct a cladogram , a diagram that shows the evolutionary relationships among a group of organisms.
    • Cladograms help scientists understand how one lineage branched from another in the course of evolution.
  • 29.
    • A cladogram shows the evolutionary relationships between crabs, barnacles, and limpets.
    Crustaceans Mollusk Crab Barnacle Limpet Tiny free-swimming larva Molted external skeleton Segmentation
  • 30.
      • The genes of many organisms show important similarities at the molecular level.
      • Similarities in DNA can be used to help determine classification and evolutionary relationships.
  • 31.
      • DNA Evidence
        • DNA evidence shows evolutionary relationships of species.
        • The more similar the DNA of two species, the more recently they shared a common ancestor, and the more closely they are related in evolutionary terms.
        • The more two species have diverged from each other, the less similar their DNA is.
  • 32.
    • Molecular Clocks
        • Comparisons of DNA are used to mark the passage of evolutionary time.
        • A molecular clock uses DNA comparisons to estimate the length of time that two species have been evolving independently.
  • 33. Molecular Clocks new mutation new mutation 2 mutations A B C A gene in an ancestral species Species Species Species new mutation 2 mutations
  • 34.
    • A molecular clock relies on mutations to mark time.
    • Simple mutations in DNA structure occur often.
    • Neutral mutations accumulate in different species at about the same rate.
    • Comparing sequences in two species shows how dissimilar the genes are, and shows when they shared a common ancestor.
  • 35. 18-3 Kingdoms and Domains
  • 36.
    • The Tree of Life Evolves
        • Systems of classification adapt to new discoveries.
        • Linnaeus classified organisms into two kingdoms—animals and plants.
        • The only known differences among living things were the fundamental traits that separated animals from plants.
  • 37.
      • There are enough differences among organisms to make 5 kingdoms:
          • Monera
          • Protista
          • Fungi
          • Plantae
          • Animalia
  • 38.
      • Six Kingdoms
        • Recently, biologists recognized that Monera were composed of two distinct groups: Eubacteria and Archaebacteria.
  • 39.
    • The six-kingdom system of classification includes:
        • Eubacteria
        • Archaebacteria
        • Protista
        • Fungi
        • Plantae
        • Animalia
  • 40. Changing Number of Kingdoms Introduced Names of Kingdoms 1700’s Late 1800’s 1950’s 1990’s Plantae Animalia Protista Plantae Monera Protista Fungi Plantae Eubacteria Archae-bacteria Animalia Animalia Animalia Protista Fungi Plantae
  • 41.
    • The Three-Domain System
        • Molecular analyses have given rise to the three-domain system of taxonomy that is now recognized by many scientists.
        • The domain is a more inclusive category than any other—larger than a kingdom.
  • 42.
      • The three domains are:
        • Eukarya, which is composed of protists, fungi, plants, and animals.
        • Bacteria, which corresponds to the kingdom Eubacteria (true bacteria).
        • Archaea, which corresponds to the kingdom Archaebacteria.
  • 43.
    • Modern classification is a rapidly changing science.
    • As new information is gained about organisms in the domains Bacteria and Archaea, they may be subdivided into additional kingdoms.
  • 44.
    • Domain Bacteria
        • Members of the domain Bacteria are unicellular prokaryotes.
        • Their cells have thick, rigid cell walls that surround a cell membrane.
        • Their cell walls contain peptidoglycan.
  • 45. Domain Bacteria
    • The domain Bacteria corresponds to the kingdom Eubacteria .
  • 46. Domain Archaea
    • Domain Archaea
        • Members of the domain Archaea are unicellular prokaryotes.
        • Archaea live in extreme environments.
        • Their cell walls lack peptidoglycan, and their cell membranes contain unusual lipids not found in any other organism.
  • 47. Domain Archaea
    • The domain Archaea corresponds to the kingdom Archaebacteria .
  • 48.
    • Domain Eukarya
        • The domain Eukarya consists of organisms that have a nucleus.
        • Eukarya includes the kingdoms
          • Protista
          • Fungi
          • Plantae
          • Animalia
  • 49. Domain Eukarya
  • 50. Domain Eukarya
      • Protista 
        • The kingdom Protista is composed of eukaryotic organisms that cannot be classified as animals, plants, or fungi.
        • Its members display the greatest variety.
        • They can be unicellular or multicellular; photosynthetic or heterotrophic; and can share characteristics with plants, fungi, or animals.
  • 51.
      • Fungi 
        • Members of the kingdom Fungi are heterotrophs with cell walls that contain chitin.
        • Most fungi feed on dead or decaying organic matter by secreting digestive enzymes into it and absorbing small food molecules into their bodies.
        • They can be either multicellular (mushrooms) or unicellular (yeasts).
  • 52. Domain Eukarya
      • Plantae 
        • Members of the kingdom Plantae are multicellular, photosynthetic autotrophs.
        • Plants are nonmotile—they cannot move from place to place.
        • Plants have cell walls that contain cellulose.
        • The plant kingdom includes cone-bearing and flowering plants as well as mosses and ferns.
  • 53. Domain Eukarya
      • Animalia 
        • Members of the kingdom Animalia are multicellular and heterotrophic.
        • The cells of animals do not have cell walls.
        • Most animals can move about.
        • There is great diversity within the animal kingdom, and many species exist in nearly every part of the planet.
  • 54.
      • Which statement about classification is true?
        • Biologists use regional names for organisms.
        • Biologists use a common classification system based on similarities that have scientific significance.
        • Biologists have identified and named most species found on Earth
        • Taxonomy uses a combination of common and scientific names to make the system more useful.
  • 55.
      • Linnaeus's two-word naming system is called
        • binomial nomenclature.
        • taxonomy.
        • trinomial nomenclature.
        • classification.
  • 56.
      • Several different classes make up a(an)
        • family.
        • species.
        • kingdom.
        • phylum.
  • 57.
      • A group of closely related species is a(an)
        • class.
        • genus.
        • family.
        • order.
  • 58.
      • Which of the following lists the terms in order from the group with the most species to the group with the least?
        • order, phylum, family, genus
        • family, genus, order, phylum
        • phylum, class, order, family
        • genus, family, order, phylum
  • 59.
      • Grouping organisms together based on their evolutionary history is called
        • evolutionary classification.
        • traditional classification.
        • cladogram classification.
        • taxonomic classification.
  • 60.
      • Traditional classification groups organisms together based on
        • derived characters.
        • similarities in appearance.
        • DNA and RNA similarities.
        • molecular clocks.
  • 61.
      • In an evolutionary classification system, the higher the taxon level,
        • the more similar the members of the taxon become.
        • the more common ancestors would be found in recent time.
        • the fewer the number of species in the taxon.
        • the farther back in time the common ancestors would be.
  • 62.
      • Classifying organisms using a cladogram depends on identifying
        • external and internal structural similarities.
        • new characteristics that have appeared most recently as lineages evolve.
        • characteristics that have been present in the group for the longest time.
        • individual variations within the group.
  • 63.
      • To compare traits of very different organisms, you would use
        • anatomical similarities.
        • anatomical differences.
        • DNA and RNA.
        • proteins and carbohydrates.
  • 64.
      • Organisms whose cell walls contain peptidoglycan belong in the kingdom
        • Fungi.
        • Eubacteria.
        • Plantae.
        • Archaebacteria.
  • 65.
      • Multicellular organisms with no cell walls or chloroplasts are members of the kingdom
        • Animalia.
        • Protista.
        • Plantae.
        • Fungi.
  • 66.
      • Organisms that have cell walls containing cellulose are found in
        • Eubacteria and Plantae.
        • Fungi and Plantae.
        • Plantae and Protista.
        • Plantae only.
  • 67.
      • Molecular analyses have given rise to a new taxonomic classification that includes
        • three domains.
        • seven kingdoms.
        • two domains.
        • five kingdoms.
  • 68.
      • Which of the following contain more than one kingdom?
        • only Archaea
        • only Bacteria
        • only Eukarya
        • both Eukarya and Archaea