1. Systematics: Seeking Order Amidst Diversity
Chapter 18:
Systematics: Seeking Order Amidst Diversity

2. 1 2 3 Systematics: The science of reconstructing phylogeny
Chapter 18: Systematics
Systematics: The science of reconstructing phylogeny
Evolutionary
history
Three natural processes underlie evolution:
1) Genetic variation exists among members of a population
2) Such variation is inherited to the next generation
3) Natural Selection: The survival and enhanced
reproduction of members with favorable variations. 1 2 3
Birds like
red frogs

3. Taxonomy: The science of naming organisms and placing
Chapter 18: Systematics
Taxonomy: The science of naming organisms and placing
them into categories based on their evolutionary
relationships (Table 18.1)
Bacteria
Archaea
Prokaryotes
(no nucleus)
Eukarya
Eukaryotes
(true nucleus)
Domain
Eukarya
Animalia
Chordata
Reptilia
Squamata
Colubridae
Thamnophis
Sirtalis
Kingdom
Phylum
Class
Order
Family
Genus
Species
Scientific
Name

4. Thamnophis sirtalis Thamnophis marcianus Thamnophis radix
Chapter 18: Systematics
Thamnophis sirtalis
Thamnophis marcianus
Thamnophis
radix

5. Based work on Aristotle (~ 350 B.C.) Introduced scientific names
Chapter 18: Systematics
“Father” of Taxonomy
Carl von Linne ( )
(Carolus Linnaeus)
Based work on Aristotle (~ 350 B.C.)
Introduced scientific names
Basis for Classification:
1) Anatomical structures (Homologous = same evolutionary origin)
2) Developmental stages
3) Genetic comparisons (DNA)

6. Chromosome comparison Sequence comparison
(Figure 18.3)
Chromosome comparison
Chapter 18: Systematics
Sequence comparison

7. system (plants / animals)
1) Monera (single-celled prokaryotes)
Chapter 18: Systematics
The Kingdoms (Proposed by Robert Whittaker ):
2) Protists (single-celled eukaryotes)
3) Fungi (multicellular; absorptive digestion)
4) Plantae (Multicellular; photosynthsis)
5) Animalia (Multicellular; ingestion)
Replaced 2 kingdom
system (plants / animals)

8. The Domains (Proposed by Carl Woese - 1990’s):
Chapter 18: Systematics
The Domains (Proposed by Carl Woese ’s):
Archaebacteria
Eubacteria
(Figure 18.5)

9. Chapter 18: Systematics
(Figure 18.6)

10. ? Taxonomies Do Change (more common further down spectrum):
Chapter 18: Systematics
Taxonomies Do Change (more common further down spectrum):
1) Emergence of New Information:
Baltimore
Oriole
Bullock’s
Oriole ?
Biological Species
Definition

11. ~ 2/3 of Earth’s biodiversity
Chapter 18: Systematics
Taxonomies Do Change (more common further down spectrum):
1) Emergence of New Information:
2) Asexual Reproducing Organisms:
Do not fit Biological Species Definition (Interbreeding)
Phylogenetic Species Concept: The smallest
discernable group that contains all the descendants
of a single common ancestor
Currently 1.4 million species are named
,000 new / year
5% prokaryote / protists
22% plants / fungi
63% animals
Tropical Rain Forest:
6% of Earth’s land area
~ 2/3 of Earth’s biodiversity
Why? Ease of locating them...