Systematics and Taxonomy Flashcards
PHYLOGENIES
- Evolutionary relationships among species
- Hierarchical family tree with descendants
branching off from ancestors
SYSTEMATICS
- Construction of phylogenies (family trees)
– Determine evolutionary relationships among species, genera, families, etc.
TAXONOMY
Uses phylogenies to name and classify organisms
IMPORTANCE OF PHYLOGENY
- Basis for identification & classification (taxonomy)
(e.g. how many species in a genus, family, etc.) - Helps explain why a species evolved certain adaptations and not others (i.e. understand when & where in the family tree certain traits evolved)
PRIMITIVE TRAIT
Traits that are inherited from a common ancestor
DERIVED TRAIT
Newly evolved traits - since the time of the
last common ancestor
APOMORPHIC
Derived traits
SYNAPOMORPHIES
Shared derived traits
CLADISTICS
- Members of a group share a common
evolutionary history, and are “closely related” - Recognized by sharing unique features not present in distant ancestors
- A method of hypothesizing relationships among organisms
HOMOLOGOUS TRAITS
Similar traits shared between organisms because they share a common ancestor
ANALOGOUS TRAITS
- Similar traits in organisms due to similar function rather than common ancestry
- Through convergent evolution
TRAIT POLARITY
primitive or derived
OUTGROUP
A species or group of species that is closely related to but not part of the group being studied
PARSIMONY
The principle that the simplest explanation for a phenomenon is the most likely to be true
MOLECULAR CLOCK
- Used for deciphering the history of when two or more species diverged from one another
- Changes in genes occur by chance, but over time, accumulate in a regular clock-like manner
- Neutral theory
NEUTRAL THEORY
Assumes most changes in genes are small and do not produce effect on phenotype or fitness
CLADISTIC TAXONOMY
- The theory that naming should be based on descent alone (more popular)
- Belong in same clade (branch of evolutionary tree)
EVOLUTIONARY TAXONOMY
The theory that naming should be based on descent but also overall similarity
PLESIOMORPHIC
Ancestral traits
Occur in last common ancestor
