BIOL 1202 : BIOLOGY 1202 EXAM 2
EXAM #2
Chapter 26
Phylogeny and Systematics
How do we classify life?
Boundaries between units in the geologic time scale are marked by dramatic biotic change.
A. 5 kingdom classification system in the use through the late 1900s.
1. Monera 2. Protista 3. Plantae 4. Fungi 5. Animalia
- Animalia gets its energy by digestion
- Planate gets its energy by photosynthesis
- Planate, fungi, and animalia are all multicellular
B. 3 domain system
1. Bacteria 2. Archea 3. Eukarya
( Categorizing in species is just like books in a library. Every time a new species is discovered, it is classified right
away.)
C. How many kingdoms?
1. Bacterial Kingdoms 2. Archean Kingdoms 3. “Protistian” Kingdoms
4. Plantae 5. Fungi 6. Animalia
** You have to classify to know what’s lost!!
Did King Philip Come Over For Gumbo Sunday?
DOMAIN- Eukarya
KINGDOM- Animalia
PHYLUM- Chordata
CLASS- Mammalia
ORDER- Carnivoria
FAMILY- Felidae
GENUS- Panthera
SPECIES- Panthera Pardus
** Most inclusive- greatest number of species (domain)
Linnaeus convinced us to use a hierarchical classification system
Darwin provided us with the mechanism by which evolution results in descent with modification
Taxonomy- naming and classifying organisms
Systematics- naming and classifying organisms according to their evolutionary relationships
Phylogenetics- reconstructing the evolutionary relationships among organisms
Macroevolution and Phylogeny
- Phylogenetic tree: hypothesized genealogy traced back to the last common ancestor through
hierarchial, dichotomous branching
**If the line is cut short, the species has become extinct.
Nodes- branch point, speciation event
Cladistics- the principles that guide the production of Phylogenetic trees, aka cladograms
(Phylogenetic tree/phylogeny/cladogram)
Lineage or clade- entire branch
Microevolution is the changes in allele frequencies that occur over time within a population
A monophyletic group is a taxon (group of organisms) which forms a clade, meaning that it contains all the
descendants of the possibly hypothetical closest common ancestor of the members of the group
Taxonomic groups often reflect true clades.
FOSSILS
With the fossil record, we can go back in time. The fossil record is especially valuable, and the only option for many
extinct taxa. However we almost never have a continuous record from one species to the next.
Cladistic principles allow us to construct hypothesized phylogenetic trees.
CLADISTIC ANALYSIS
-Fossils provide morphological data for extinct species, whereas comparisons of multiple types of traits – including
molecular – do so for extant species.
-Similar characters (ex: morphological, behavioral, molecular, etc) suggest relatedness.
***Not all similarity derives from common ancestry!!!
-Convergent Evolution can produce superficially similar traits that lack homology with one another.
-Homologous: share common ancestry (lack of similarity among taxa results from divergence)
-Analogous: no common ancestry (similarity among taxa results from convergence)
-As a general rule, the more homologous characters shared by two species, the more closely related they are.
-Sequences of DNA and RNA (nucleotides) and proteins (amino acids) are used as characters; as a general rule, the
more recently two species shared a common ancestor, the more similar their sequences.
-Each nucleotide can be treated as a character
-character changes=mutations
*****
-The sequence of branching in a cladogram then represents the sequence in which evolutionary novelties (shared
derived characters) evolved
INGROUP VS OUTGROUP
In group: the group whose relationships we are trying to resolve
- Shared derived or shared ancestral (homologous)
Out group: a species known to have an older most recent common ancestor with the in group than the in group’s
most recent common ancestor
Document Summary
Boundaries between units in the geologic time scale are marked by dramatic biotic change: 5 kingdom classification system in the use through the late 1900s, monera 2. Planate, fungi, and animalia are all multicellular: 3 domain system, bacteria 2. Eukarya ( categorizing in species is just like books in a library. Every time a new species is discovered, it is classified right away. : how many kingdoms, bacterial kingdoms 2. ** you have to classify to know what"s lost! ** most inclusive- greatest number of species (domain) Linnaeus convinced us to use a hierarchical classification system. Darwin provided us with the mechanism by which evolution results in descent with modification. Systematics- naming and classifying organisms according to their evolutionary relationships. Phylogenetic tree: hypothesized genealogy traced back to the last common ancestor through hierarchial, dichotomous branching. **if the line is cut short, the species has become extinct. Cladistics- the principles that guide the production of phylogenetic trees, aka cladograms (phylogenetic tree/phylogeny/cladogram)
