Download I. Systematic Biology A. Taxonomy is the branch of biology

AP Biology
Chapter 19 Review
I.
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B.
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Systematic Biology
Taxonomy is the branch of biology concerned with identifying, naming, and
classifying organisms.
In the mid-eighteenth century, Carolus Linnaeus developed the system of binomial
nomenclature
1. First word is the genus name (capitalized)
2. Second word is the specific epithet (lowercase)
3. A species is referred to by the full binomial name (Genus species)
Modern taxonomists use the following classification:
1. Species, Genus, Family, Order, Class, Phylum, Kingdom, Domain
Three-Domain System
Domain Bacteria
1. Prokaryotic unicellular organisms that
reproduce asexually.
2. Most bacteria are heterotrophic, some
autotrophic (like cyanobacteria)
3. Important in ecosystems - keeping
chemical cycling going.
4. Some bacteria are parasitic and cause
disease.
Domain Archaea
1. Prokaryotic unicellular organisms that
reproduce asexually.
2. Live in extreme environments.
3. Cell wall is diverse but not the same as
the bacterial cell wall.
Domain Eukarya
1. Unicellular and multicellular
organisms
2. Cells with a membrane-bounded nucleus
3. Sexual reproduction is common
4. Contains four kingdoms
a. Kingdom Protista
b. Kingdom Fungi
c. Kingdom Plantae
d. Kingdom Animalia
AP Biology
Chapter 19 Review
III.
Phylogeny
A. One goal of systematics is to determine phylogeny (evolutionary history) of a group
B. Phylogeny is often represented as a
phylogenetic tree (A diagram indicating lines
of descent)
C. Each branching point:
1. Is a divergence from a common ancestor
2. Represents an organism that gives rise to
two or more new groups
D. Ancestral traits: Present in all members of a
group, and present in the common ancestor
E. Derived traits: Present in some members of a
group, but absent in the common ancestor
F. Cladistics is a way to analyze primitive and
derived characters and by the construction of
phylogenetic trees called a cladogram on the
basis of shared derived characters.
1. Guided by the principle of parsimony—
the minimum number of assumptions is most logical.
2. The best cladogram is one in which the fewest number of shared derived characters are
left unexplained or that minimizes the number of assumed evolutionary changes.
IV.
Tracing Phylogeny
A. Fossil Traits
1. Fossil record is incomplete
2. It is often difficult to determine the phylogeny of a fossil
B. Homology
1. Refers to features that stem from a common ancestor
2. Homologous structures are related to each other through
common descent
C. Analogy
1. Similarity due to convergent evolution
2. Analogous structures have the same function in different
groups but do not have a common ancestry
3. Structures look similar due to adaptation to similar
environments
D. Behavioral Traits
1. Parental care, mating calls, etc.
E. Molecular Traits
1. Two species with similar base-pair sequences are assumed to be closely related
2. Two species with differing base-pair sequences are assumed to be only distantly related
3. DNA Sequence Alignment
4. Protein Comparisons
a. Amino acid sequencing
b. Similar sequence in the same protein indicates a close relationship