Chapter 23 Flashcards
what is systematics?
the study of evolutionary relationships
What can you construct with systematics?
an evolutionary tree, or phyologeny
What is phyologeny?
the evolutionary history of an organism, including which species are closely related and in what order related species evolved
With a branching diagram depicting evolutionary relationships, what causes all species to be related in branching?
Descent modification
True or false: Evolution can occur very rapidly or very slowly
True
True or False: evolution is not always divergent
True, it can also be convergent
What is evolutionary reversal?
the process in which a species ca re-evolve the characteristics of an ancestral species
What does it mean if a trait is ancestral?
There is a similarity among species that is inherited from the most recent common ancestor of the group
What does it mean if a trait is derived?
There is the similarity that arose more recently (not from a common ancestor)
What is cladistics?
A taxonomic technique used for creating hierarchy or organisms that represent true phylogenetic relationships and descent
What type of traits are characters considered informative?
derived
What are the different types of data that systematics can gather on a number of characteristics?
- phenotype
- morphology
- physiology
- behavior
- DNA
What does it mean to polarize?
To determine whether a character state are ancestral or derived
What is a character state?
one of two or more distinguishable forms of a character ( ex. presence or absence of vertebrate
What is used to assign character polarity?
an outgroup
What is an outgroup?
a species or group of species that is closely related, but not a member of the group under study
What is a clade?
species that share a common ancestor
What is synapomorphy?
a derived character shared by clade member
What are plesiomorphies?
ancestral states
What is symplesiomorphy?
shared ancestral states
What are some complications with constructing a cladogram?
the same character could have evolved independently in several species
2. re-evolve evolution
What is Homoplasy?
a shared derived character state that has not been inherited from a common ancestor
What is the principle of parsimony?
scientists should favor the hypothesis that required the fewest assumptions
What is the statistical approach?
an assumption about the rate at which characters evolve and then fit the data to these models to derive the phylogeny that best accords with these assumptions.
What is the molecular clock?
the metric in which the rate of evolution
what is classification?
how we place species and higher groups-genus, family, class, and so forth- into the taxonomic hierarchy
What is taxonomy?
the science of classifying living things
What is the first word used to classify a species?
The genus to which the organism belongs to
What is the second word in classifying a species?
particular species
____ with common properties are in the same class
order
_____ have similar characteristics and same phylum
classes
____ are assigned to kingdoms
phyla
What includes the most recent common ancestor of the group and all of its descendants?
monophyletic
What is the term for when it includes the most recent common ancestors of the group but not all its descendants?
paraphyletic
What is group does not include the most recent common ancestors of all members in the group?
polyphyletic
What is the phylogenetic species concept?
it proposes that the term species should be applied to a group of populations that have been evolving independently of other groups of populations
What are some controversies with the phylogenetic species concept?
- it can lead to the recognition of every slightly differentiated species population as a distinct species
- species may not always be monophyletic
What is a homologous structure?
they are derived from the same body part of a common ancestor
what is a homoplastic structure?
they are not derived from a common ancestor
