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Linnaeus’ System of Taxonomy

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Presentation on theme: "Linnaeus’ System of Taxonomy"— Presentation transcript:

1 Linnaeus’ System of Taxonomy
Used a hierarchical system Kingdom, Phylum, Class, Order, Family, Genus, Species (later Domain was added) Based on molecular evidence (DNA and protein sequences) its accepted to have 6 Kingdoms and have added 3 Domains

2 Latinized descriptive names of organisms - Binomial Nomenclature: 2 word scientific naming system
First part of binomial – Genus – Always capitalized Second part – species - always lower case. Latin scientific names are always italicized (if word processing) or underlined (if hand written) Ex. Homo sapiens, “wise man” species – specific group of 1 type of organism that may interbreed and produce viable, fertile offspring.

3 Binomial Nomenclature – Who cares?
What do you call this? Crawdad? Crawfish? Crayfish? Prairie crayfish-Procambarus gracilis

4 Why use Binomial Nomenclature?
Problems with common names Varies from area to area, therefore, no commonality. Does not specify a particular species. Each animal has an unique binomial name. Required for all animals by International Code of Zoological Nomenclature.



7 Domain Archaea Domain Eubacteria
Prokaryotic microbes, tiny Live in extreme environments: high temps, salts, & acids (tough) Anaerobic Most primitive Prokaryotic microbes Often called the “true bacteria” Live in most environments Anaerobic or aerobic


9 Domain Eukarya Eukaryotic Mainly aerobic but can be anaerobic
Includes all other kingdoms (Protista, Plant, Fungi, Animal)

10 6 Kingdoms

11 Common Animal Phylum

12 What is this?

13 Most recently described Phylum - Cycliophora
36th found Phylum in 1995 In the Animal Kingdom Symbion pandora Found in mouthparts of Norwegian lobsters 0.3 mm long = 300 µm

14 Currently we use Morphological, biochemical, fossil, and molecular comparisons to infer evolutionary relationships

15 Though sedimentary fossils are the most common
Paleontologists study a wide variety of fossils (a) Dinosaur bones being excavated from sandstone (g) Tusks of a 23,000-year-old mammoth, frozen whole in Siberian ice (e) Boy standing in a 150-million-year-old dinosaur track in Colorado (d) Casts of ammonites, about 375 million years old (f) Insects preserved whole in amber (b) Petrified tree in Arizona, about 190 million years old (c) Leaf fossil, about 40 million years old

16 Morphological and Molecular Homologies
In general, organisms that share very similar morphologies or similar DNA sequences Are likely to be more closely related than organisms with vastly different structures or sequences. Not always true! Analogy vs. Homology

17 Homology Homologous Structures – structures in different species that are similar because of commons ancestry.

18 Analogy Analogous Structures – similarity in structures due to adaptations and not a common ancestor.

19 Cladograms

20 Cladistics a method that applies the scientific method to the construction of evolutionary relationships.

21 Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as: vertebrae jaw bones four legs amniotic eggs hair

22 Cladogram Vocabulary Branch point Ingroup Outgroup
2 species differ in shared derived characters Ingroup monophyletic group we are interested in Outgroup species or group of species that is most closely related to an ingroup

23 Primate Cladogram

24 Each branch point Represents the divergence (separation) of two species


26 What shared derived character is common to:
salmon lizard rabbit but not the lamprey?

27 Constructing a cladogram
Choose species Choose characters Each character has different character states (example: tail or no tail) Determine order of character states primitive or derived? Use the fossil record Many simple parts came before fewer, more specialized parts Vestigial organs –not functioning but present) Mutation rate of DNA nucleotides Group species (or higher taxa) based on shared derived characteristics

28 Constructing a cladogram
Build a cladogram based on All species are placed on tips in the phylogenetic tree, not at branch points Each cladogram branch point should have a list of one or more shared derived characters that are common to all species above the branch point unless the character is later modified All shared derived characters appear together only once in a cladogram unless they arose independently during evolution more than once Choose the most likely cladogram among possible options

29 Construct a Cladogram for Us
Construct a Cladogram for Us! Let’s use the characters of tail, fur, and # of limbs

30 Gorilla Four limbs Fur No tail

31 Tiger Four limbs Fur Tail

32 Lizard Four limbs Tail

33 Fish Tail

34 Chimpanzee Four limbs Fur No tail

35 Clade With 4 Limbs

36 Clade With Fur

37 Clade With No Tail

38 Characteristics (Traits) for Constructing this Cladogram
Tail is the most ancestral Four limbs is the oldest derived trait Fur is a later derived trait Loss of tail is the most derived trait

39 One Possible Cladogram
Gorilla Chimpanzee Tiger Lizard Fish Tail Lost Fur Four Limbs

40 A Vertebrate Cladogram
Birds Mammals Reptile Amphibian Fish Four Limbs Amniotic Egg Endothermic Fur Feathers Vertebrae Lancelet Outgroup

41 The outgroup comparison
Enables us to focus on just those characters that were derived at the various branch points in the evolution of a clade. Salamander TAXA Turtle Leopard Tuna Lamprey Lancelet (outgroup) 1 Hair Amniotic (shelled) egg Four walking legs Hinged jaws Vertebral column (backbone) Amniotic egg Vertebral column (a) Character table. A 0 indicates that a character is absent; a 1 indicates that a character is present. (b) Cladogram. Analyzing the distribution of these derived characters can provide insight into vertebrate phylogeny. CHARACTERS


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