Lecture 2 - Taxonomy & Systematics (Part 2) Flashcards
What is Systematic?
The theory and a little practice of classifying organisms.
The “Why”
What are people called when they engage in Systematics?
Systematists
What do modern Systematists focus on?
They focus on the reason why particular taxa should be group together.
ie. The evolutionary reason why things should be grouped together.
What major change happened to systematics in 1960?
The focus was switched from simply adding new taxa to methods for determining relatedness among taxa.
Why did the old taxonomies need to be changed in the 1960’s?
They were changed out of the desire for evolutionary informative classifications
What was one of the major results of the taxonomies change in the 1960s?
Taxonomies in textbooks rapidly became out of date.
What is molecular systematics?
it is the use of molecular genetics to study the evolution of relationships among individuals and species
What has the rise of molecular systematics done to taxonomies?
It has accelerated the rate of change, due to the use of proteins. DNA, and RNA to better study the relationships of species.
What is the 5 kingdom classification?
Bacteria Protista Plantae Fungi Animalia
What is the modern “kingdom” classification?
It involves 10 kingdoms with a new taxonomic level, the domain.
What was systematics like before the 1960’s?
it was a Relatively unstructured discipline, although systematists wanted to create a evolutionary sensible classification
What is stratigraphy?
The temporal order in which fossils occur
What tools did systematists have before the 1960’s to classify species?
- Stratigraphy
- Expertise
- Primitive and advanced morphology
What is Primitive morphology?
Morphology based more off of guesses
What is advanced morphology?
Morphology based on facts, compared to other facts.
What was one of the major flaws with “old-style” systematics?
The methods were subjective, choosing witch classification was the best could be strongly influenced by personal preference.
What invention in the 1960’s allowed for a more objective classification of species within systematics
The computer.
Who invented Hennigs systematics? When?
German Entomologist Willi Hennig in the 1950’s
What drove the creation of the creation of the Hennigan systematics system?
The want for classifications that reflected ancestor-descendant relationships (or more generally shared evolutionary history)
When creating Hennigan systematics, what goal did Willi have in mind?
To create a method that was as objective, and transparent as possible.
What did Hennigan systematics argue the best way to determine evolutionary relationships was?
Focus on only the shared, derived characteristics.
What is a group of organisms that is related by shared and derived characteristics called?
A Calde
What was Hennig’s approach to determining evolutionary relationships called?
Cladistics or phylogentic systematics
What does Clados mean?
Branch
What does Phylon mean?
Tribe, or race
What does gen mean?
Create
What is a cladogram?
A branching diagaram that shows the hypothesized relationships between species.
What does gramm mean?
A mark or a line
What do Cladograms represent?
Only the order of evolutionary events (branching) and what taxa share most recent common ancestors.
What do the lengths of the branches on a cladogram mean?
Nothing at all