Week 9- Systematics and Phylogeny Flashcards
A scientific field used to organize and classify
organisms based on evolutionary relationships.
Systematics
By combining data/evidences from many sources,
scientists can put together the ____________ of an
organism.
Phylogeny
Evidences for systematics, or creating phylogenies:
Morphological (Homologies)
Molecular (Homologies)
Segregating Homologous and
Analogous Features
MORPHOLOGICAL (HOMOLOGIES):
Paleontology
Comparative Anatomy
Comparative Embryology
MOLECULAR (HOMOLOGY):
Molecular Genetics
a biological classification system that involves the
categorization of organisms based on shared traits.
Cladistics
Biologists attempt to place species into groups called _________, each of which includes an ancestral species and all of its descendants.
Clades
3 Phyletic Grouping
Monophyletic
Paraphyletic
Polyphyletic
Consists of an ancestral species and all of its descendant
Monophyletic
Consists of an ancestral species and some of its descendant but not all of them
Paraphyletic
The common ancestor of its members is not part of the group (Latest Only)
Polyphyletic
It is a diagram used to reflect evolutionary relationships among organisms or groups of organisms. It is hypothetically used to
determine evolutionary past.
Phylogenetic Tree
a scientifically classified group or entity : a taxonomic unit of any rank.
Taxon (Taxa)
Biologists use phylogenetic trees for many purposes, including:
A) Testing Hypotheses about evolution
B) Learning about the characteristics of extinct species and ancestral lineages
C) Classifying Organisms
Parts of a Phylogenetic Tree
Branch Point
Basal Taxa
Sister Taxa
Polytomy
where a single lineage evolved into a distinct
one.
Branch Point
A lineage that evolved early from the root and
remains unbranched
Basal Taxa
When two lineages stem from the same branch
point.
Sister Taxa
A branch with more than two lineages.
Polytomy
Phylogenetic Tree is also know as __________________
Tree of Life
Key points about phylogenetic trees
- It is intended to show patterns of descent, not phenotypic similarity.
- The sequence of branching in a tree does not necessarily indicate the actual (absolute) ages of the particular species.
- We should not assume that a taxon on a phylogenetic tree evolved from the taxon next to it.
the study of the general principles of scientific
classification. Same definition with ‘systematics’.
Taxonomy
The taxonomic system was devised by ___________________.
Carolus Linnaeus (1707-1778)
It is a hierarchical system since organisms are grouped into ever more inclusive categories from species up to kingdom.
Taxonomic System
In 1981, a category higher than a kingdom, called
__________, was proposed by ______________.
Domain, Carl Woese