1. TAXONOMY
Early taxonomists classified all species as either plants or animals
Later, five kingdoms were recognized: Monera (prokaryotes), Protista, Plantae, Fungi, and Animalia
More recently, the three-domain system has been adopted: Bacteria, Archaea, and Eukarya
The three-domain system is supported by data from many sequenced genomes 1

2. Euglenozoans Forams Diatoms Ciliates Domain Eukarya Red algae
Green algae
Land plants
Amoebas
Fungi
Animals
Nanoarchaeotes
Archaea
Domain
Methanogens
COMMON
ANCESTOR
OF ALL LIFE
Thermophiles
Figure The three domains of life
Proteobacteria
(Mitochondria)*
Chlamydias
Spirochetes
Domain Bacteria
Gram-positive
bacteria
Cyanobacteria
(Chloroplasts)* 2

3. Classification systems
Six-Kingdom Scheme
Classification systems 3

4. Domains Bacteria and Archaea are single-celled prokaryotes
The three-domain system highlights the importance of single-celled organisms in the history of life
Domains Bacteria and Archaea are single-celled prokaryotes
Only three lineages in the domain Eukarya are dominated by multicellular organisms, kingdoms Plantae, Fungi, and Animalia 4

5. Comparative Morphology
Study of similarities and differences in body plans of major groups
Puzzling patterns:
Animals as different as whales and bats have similar bones in forelimbs
Some parts seem to have no function
Guiding principle:
When it comes to introducing change in morphology, evolution tends to follow the path of least resistance

6. Morphological Divergence
Change from body form of a common ancestor
Produces homologous structures

7. Comparative pelvic anatomy
Comparative Morphology
Comparative pelvic anatomy

8. Morphological Convergence
Individuals of different lineages evolve in similar ways under similar environmental pressures
Produces analogous structures that serve similar functions

9. Morphological Convergence

10. Comparative Development
Each animal or plant proceeds through a series of changes in form
Similarities in these stages may be clues to evolutionary relationships
Mutations that disrupt a key stage of development are selected against

11. Similar Vertebrate Embryos
Alterations that disrupted early development have been selected against
FISH
REPTILE
BIRD
MAMMAL

12. Comparative Biochemistry
Kinds and numbers of biochemical traits that species share is a clue to how closely they are related
Can compare DNA, RNA, or proteins
More similarity means species are more closely related

13. Comparing Proteins
Compare amino acid sequence of proteins produced by the same gene
Human cytochrome c (a protein)
Identical amino acids in chimpanzee protein
Chicken protein differs by 18 amino acids
Yeast protein differs by 56

14. Taxonomy
Field of biology concerned with identifying, naming, and classifying species
Somewhat subjective
Information about species can be interpreted differently 14

15. Binomial System Devised by Carl von Linneas
Each species has a two-part Latin name
First part is generic
Second part is specific name 15

16. Higher Taxa
Kingdom
Phylum
Class
Order
Family
Genus
Species 16

17. Kingdom: Animalia Domain: Bacteria Domain: Archaea Domain: Eukarya
Species: Panthera pardus
Genus: Panthera
Family: Felidae
Order: Carnivora
Class: Mammalia
Figure 20.3 Linnaean classification
Phylum: Chordata
Kingdom:
Animalia
Domain:
Bacteria
Domain:
Archaea
Domain:
Eukarya 17

18. Examples of Classification18

19. Cladistics Cladistics classifies organisms by common descent
A clade is a group of species that includes an ancestral species and all its descendants 19

20. A valid clade is monophyletic, signifying that
it consists of the ancestor species and all its descendants A 1 B
Group I C D
Figure 20.10a Monophyletic, paraphyletic, and polyphyletic groups (part 1: monophyletic) E F G 20

21. A paraphyletic grouping consists of an ancestral species
and some, but not all, of the descendants A B C D
Figure 20.10b Monophyletic, paraphyletic, and polyphyletic groups (part 2: paraphyletic) E
Group II 2 F G 21

22. A polyphyletic grouping consists of various taxa
with different ancestors A 1 B
Group III C D
Figure 20.10c Monophyletic, paraphyletic, and polyphyletic groups (part 3: polyphyletic) E 2 F G 22

23. (a) Monophyletic group (clade) (b) Paraphyletic group
(c) Polyphyletic group A A A 1 1 B
Group I B B
Group III C C C D D D E E
Group II E 2 2 F F F G G G 23

24. Shared Ancestral and Shared Derived Characters
In comparison with its ancestor, an organism has both shared and different characteristics
A shared ancestral character is a character that originated in an ancestor of the taxon
A shared derived character is an evolutionary novelty unique to a particular clade
A character can be both ancestral and derived, depending on the context 24

25. Phylogenetic Trees with Proportional Branch Lengths
In some trees, the length of a branch can reflect the number of genetic changes that have taken place in a particular DNA sequence in that lineage
Drosophila
Lancelet
Zebrafish
Frog
Chicken
Human
Mouse 25

26. In other trees, branch length can represent chronological time, and branching points can be determined from the fossil record
Drosophila
Lancelet
Zebrafish
Frog
Figure Branch lengths can indicate time
Chicken
Human
Mouse
PALEOZOIC
MESOZOIC
CENOZOIC
251
65.5 Present
542
Millions of years ago 26

27. Evolutionary tree diagram
Evolutionary Trees
Evolutionary tree diagram

28. Evolutionary Trees extinction (branch ended before present)
new species
branch point (a time of divergence, speciation)
a single lineage
a new species
extinction (branch ended before present)
dashed line (only sketchy evidence of presumed evolutionary relationship)

29. Evolutionary Trees species 2 species 3 species 1 suspected branching
a single lineage; ancestral stock
branch point (time of genetic divergence, speciation under way)

30. A Cladogram
shark
mammal
crocodile
bird
feathers
fur
lungs
heart

31. Interpreting a Cladogram

32. Fig a,b, p.312

33. Constructing a Cladogram

34. Constructing a Cladogram

35. Constructing a Cladogram

36. Constructing a Cladogram

37. Constructing a Cladogram