Introduction To Cladistics Flashcards
(38 cards)
What is Systematics
Systematics is the branch of biology concerned with the study of organic diversity
What was Hennig famous for?
Nowadays, biologists refer to Hennig’s unique approach as “cladistic analysis”, “cladistics”, or “phylogenetic systematics”.
evolutionary history (i.e., phylogeny) consists of a series of what ?
evolutionary history (i.e., phylogeny) consists of a series of dichotomies.
What does Each dichotomy mark?
Each dichotomy marks the splitting and disappearance of an ancestral species and the formation of two daughter species
What is The fundamental product of evolution?
The fundamental product of evolution is the clade, or monophyletic group, which is made up of an ancestral species and all of its descendants.
What is a clade, or monophyletic group
which is made up of an ancestral species and all of its descendants.
Another word for clade is?
monophyletic group
What occurs at a node
a speciation event occurs at the branch point, or node, to give rise to a pair of daughter species
any branch that connects two nodes (remember, a node represents a speciation event) corresponds to what ?
any branch that connects two nodes (remember, a node represents a speciation event) corresponds to an ancestor
This process of species creation is
known as what?
cladogenesis, or branching evolution.
what do you use to Depict phylogenetic history?
a cladogram
can the taxa be living and extinct in a cladogram?
These taxa may be living or extinct
.
what does a node represent?
a node represents a
speciation event, it corresponds to an ancestor
is a cladogram a hypothesis, or a fact?
cladogram is an hypothesis, not a fact.
what is the difference between a phylongeny and a cladogram?
A phylogeny provides information about the evolutionary relationships among taxa. It often expresses the geographical distributions or morphological similarities of taxa as well. Most importantly, a phylogeny, unlike a cladogram, has an absolute time axis. In a phylogeny, the taxa under study are not necessarily listed across the top of the diagram, as is mandatory in a cladogram. Instead, the taxa are ordered vertically to indicate when they lived
what is the most important diference between a cladogram and a phylogeny?
Most importantly, a
phylogeny, unlike a cladogram, has an absolute time axis.
what can be used to determine common ancestry?
the geneological relationships within a suite of taxa can be discovered indirectly by examining their characters.
what is a character?
A character is a feature that is an observable part or attribute of an organism. An example of a character is feet in tetrapods.
what are the different forms of characters called?
Characters have
different forms or appearances called character states
what two things must be considered when choosing characters?
- the character has to be consistent in all the members of that type of organism.
- In selecting the suite of characters to be compared, each organism must have at least one character different from the other organisms
what is A plesiomorphy?
A plesiomorphy is an “ancestral”, “less specialized”, or “primitive” character
what is An apomorphy?
An apomorphy is a “derived”, “specialized”, or “advanced” character.
True/ False: Every taxon possesses a
mixture of plesiomorphies and apomorphies.
true:Every taxon possesses a
mixture of plesiomorphies and apomorphies.
what is Outgroup comparison ?
Outgroup comparison is a means of determining which character in a transformation series is a plesiomorphy and which is an apomorphy.