Chapter 26 Flashcards
Phylogenies
the history of a species or group of related species
Fossil Record
provides information about ancient organisms
- is based on the sequence in which fossils have accumulated in strata and may reveal ancestral characteristics that have been lost over time
Phylogenies use
Systematics as an analytical approach to understanding the diversity and relationships of organisms, both present-day and extinct
Systematics use
Morphological (shape), functional, biochemical, and molecular comparisons to infer biological relationships or similarities
Sedimentary Rocks
the richest source of fossils and are deposited into layers called Strata
Paleontologists
study a wide variety of fossils
Radiometric dating of the …
Siloam Tunnel, Jerusalem
_reign of King Hezekiah
Modern scientific methods may be used to
independently date structure that are mentioned in the Biblical text, to evaluate its historical authenticity
No well-identified Biblical structure has been radiometrically dated until now
they report sedimentary, radiocarbon, and U-Th dating of the Siloam Tunnel providing its Iron Age II date
Siloam Tunnel
was used to deliver water to the city under the protective walls
Conclusion of the Siloam Tunnel
- the Biblical text presents an accurate historical record of the Siloam Tunnel’s construction
- the dating also REFUTES a claim that the tunnel was constructed in the 2nd century b.c.
- John 9
Phylogenetic History
can be inferred from certain morphological and molecular similarities
Organisms that share very similar morphologies or similar DNA sequences are…
likely to be more closely related than organisms with vastly different structures or sequences
Analogous
similar
Homoplasies
analogous body structures or molecular sequences between two organisms
Homology
the amount of similar morphological, DNA, RNA or amino acid sequences between organisms
Molecular systematists
- analyze DNA segments from different organisms
- the more nucleotide similarity, the closer related two organisms may be
-i.e. 22 nucleotides compared, 5 similarities (homologous nucleotides)
Taxonomy
the ordered division of organisms into categories based on a set of characteristics that assess their similarities and differences
Binomial nomenclature
the two-part formate of the scientific name of an organism developed by Carolus Linnaeus (1748)
Carolus Linnaeus
1748
- developed the binomial nomenclature
- introduced a hierarchical system for grouping species in increasingly broad categories
Binomial name of an organism or scientific epithet is …
latinized and is genus and species
-i.e. Homo sapiens (humans)
Hierarchical System order
(more specific) - Species - Genus - Family - Order - Class - Phylum - Kingdom - Domain (less specific)
Systematics depict organism relationships by using
branding phylogenetic trees where each branch point represents the divergence of two species
“Deeper” branch points
represent progressively greater amounts of divergence
Phylogenetic systematics
informs the construction of phylogenetic trees based on shared characteristics
Cladogram
depiction of patterns of shared characteristics among taxa
Clade within a cladogram
is defined as a group of species that includes an ancestral species and all its descendants
Clades
can be nested within larger clades, but not all groupings or organisms qualify as clades
Cladistics
the study of resemblances among clades
3 types of clades
1) Monophyletic
2) Paraphyletic
3) Polyphyletic grouping
Monophyletic
a valid clade
consists of the ancestor species and all its descendants
Paraphyletic
grouping that consists of an ancestral species and some, but not all, of the descendants
Polyphyletic grouping
includes numerous types of organisms that lack a common ancestor
Cladistic analysis
clades are defined by their specific novelties or uniqueness
Shared Primitive Character
- a homologous structure that predates the branching of a particular clade from other members of that clade
- is shared BEYOND the Taxon we are trying to define
the branching pattern of a phylogenetic tree is
relative rather than absolute in terms of representing the timing of divergences
Phylogram
the length of a branch in a cladogram reflects the relative number of changes in that lineage
3 great clades called domains
1) Bacteria
2) Archaea
3) Eukarya
(the early history of these domains is not yet clear)
Maximum Parsimony and
Maximum Likelihood
systematists can never be sure of the single best tree but can only narrow the possibilities by applying these principles
Maximum Parsimony Tree
a phylogenetic hypothesis that requires the fewest organism changes to have occurred to form shared character(s)
Principle of Maximum Likelihood
a tree can be found that reflects the most likely sequence of historical events
The best hypotheses for phylogenetic trees are those that fit the most data:
- Morphological
- Molecular
- Fossil
(sometimes there is compelling evidence that the best hypothesis is not the most parsimonious)
