1. Chapter 18: Classification

2. 18-1: History of Taxonomy

3. Early Systems of Classification
Taxonomy: branch of biology that names and groups organisms according to their characteristics and evolutionary history

4. Aristotle
2,000 years ago
Plants: three categories based on their stems
Animals: based on where they live
Land
Water
Air

5. Problems Scientific exploration  discover MANY new species
Common name did not describe actual animal
Ex: Jellyfish: NOT a fish
Common names varied by location

6. Linnaeus’ System Swedish naturalist, Carolus Linnaeus, (1707-78)
Used organisms morphology to categorize it
Form and structure

7. Levels of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Kings Play Chess On Funny Green Squares

10. Binomial Nomenclature
Species name has two parts:
Genus
Species identifier: descriptive word
Ex: Homo sapien
Homo is the genus
sapien means “wise”

11. Further Naming and Classifying
Botanists (plants) further classify
Varieties: subset of species
Subspecies: zoologists refer to species that occur in different geographic locations
Phylogeny: evolutionary history

12. 18-2: Modern Phylogenetic Taxonomy
Past:
Morphology
Preset:
Chromosomal characteristics
Nucleotide and amino acid sequences
Embryonic development

13. Systematics
Organizes tremendous diversity of living things in the context of evolution
Phylogenetic tree: a family tree that shows the evolutionary relationships thought to exist among groups of organisms
Represents a hypothesis
Based on multiple lines of evidence
Subject to change

15. The Fossil Record Often provides clues to evolutionary relationships
HOWEVER:
Some fossil records very complete (ocean-living invertebrates) others are missing large portions

16. Morphology
Compare morphology of organism to morphology of other living things
Homologous features show descent from common ancestors

17. Embryonic Patterns of Development
Early on in development most living things look very similar
As they develop it is easier to see how their morphology differs

18. Chromosomes and Macromolecules
DNA, RNA, and proteins
Number of amino acid differences is a clue to how long ago two species diverged from a shared ancestor
Problem: ASSUMES all changes to sequence occur at random and NOT natural selection

19. Karyotype
Some similar bands on chromosomes, more related two organisms are

20. Cladistics
Uses shared derived characters of organisms to establish evolutionary relationships
Derived characters: feature that apparently evolved only within the group under consideration
Cladograms: ancestry diagrams made by means of cladistical analysis

21. 18-3:Two Modern Systems of Classification

22. Six-Kingdom System Archaebacteria Eubacteria Protista Fungi Plantae
Animalia

23. Kingdom Archaebacteria
Unicellular prokaryotes
Distinctive cell membrane
Autotrophs: chemiosmosis (use elements/chemicals for energy)

24. Many live in very harsh environments
Hot spring
VERY salty water
Anaerobic environments (No air)
Archae- in Greek means “ancient”
FIRST organisms on Earth
Reproduce: Binary fission
Nutrition: Autotrophs and heterotrophs

25. Kingdom Eubacteria Unicellular prokaryotes Eu- means “true”
Most bacteria that affect your life
Tooth decay
Milk  yogurt
Food poisoning
Reproduce: Binary fission
Nutrition: Autotrophs and heterotrophs

26. Kingdom Protista Eukaryotic and prokaryotic Difficult to describe
All eukaryotes that are not fungi, plants, or animals
Reproduction: sexual cycles unknown but they do exchange genetic info
Nutrition: Autotrophs AND heterotrophs
Euglena can photosynthesize
Amoeba eats other organisms

27. Kingdom Fungi Unicellular and multicellular eukaryotes
Reproduction: sexual cycles unknown but they do exchange genetic info
Nutrition: Heterotrophs; Absorb nutrients
Ex: puffballs, mushrooms, rusts, molds

28. Kingdom Plantae Multicellular plants
Reproduction: most have sexual cycle based on meiosis
Nutrition: All but a few are heterotrophic

29. Kingdom Animalia Multicellular Eukaryotic
Reproduction: Sexual by means of meiosis forming gametes
Nutrition: Heterotrophs
Most have body symmetry and move about environment

30. Three-Domain System In 1977, molecular biologist, Carl Woese
Classified by comparing ribosomal RNA
Why? All organisms have ribosomes so we can look at every living thing’s rRNA and compare it with others
Three main domains:
Domain Archae
Domain Bacteria
Domain Eukarya

32. Domain Archae
Same as the kingdom Archaebacteria (in six kingdom system)

33. Domain Bacteria
Same as kingdom Eubacteria

34. Domain Eukarya Protists, fungi, plants, and animals
Have nuclei with linear chromosomes and membrane bound organelles