BIOL 1105 Lesson 23: Systematics

Flashcards for BIOL 1105 Lesson 23: Systematics

True of false: The fossil record does NOT offer a complete picture.

True

What is the reconstruction and study of evolutionary relationships?

Systematics

Systematists construct evolutionary trees called ____________ to present hypotheses about relationships among species.

phylogenies

A _____________is a type of phylogeny that does not include any type of scale for the evolutionary changes that depicts.

cladogram

Phylogenies are essentially ________________________ based on the best available data.

hypotheses about the way groups of organisms are related

Phylogenies must be rooted with an __________to be meaningful,

outgroup

An ___________ is taxa that are closely related, but not direct members of the group being studied.

Outgroup

Species that share a common ancestor are said to be part of a _______.

clade

Which states that the phylogeny that requires the fewest evolutionary events is considered to be the best hypothesis of the relationships between the taxa being studied?

the principle of parsimony

Similarity between species that is inherited from the most recent common ancestor is called _________.

derived

Similarity that arose prior to the common ancestors is referred to as ____________.

ancestral

You must always polarize the characters by including an _________to determine which states are ancestral and which are derived.

outgroup

True or false: Only shared derived characters are considered informative.

True

The phylogeny is established by considering…

Which taxa has shared derived characters

True or false: Shared ancestral states can be used to make the phylogeny.

False

True or false: Similarity may NOT accurately predict evolutionary relationships.

True

___________ refers to a shared character state that has not been inherited from a common ancestor.

Homoplasy

What are two potential causes of homoplasy?

Convergent evolution and evolutionary reverses

__________________describes situations in which similar traits have evolved independently, not from a common ancestor.

Convergent evolution

____________________ describes a situation in which a trait has reverted back to an earlier state.

Evolutionary reversal

The phylogeny that represents the ___________(most/fewest) evolutionary events is considered to be the best hypothesis.

fewest

Computer Programs are necessary to_______________ and determine the most parsimonious phylogeny.

analyze large datasets

DNA Sequence Data provides______________________________, making it a preferred method. 

more characters than morphological traits

Phylogenies offer much insight about evolutionary relationships, but many do not provide information about _________ of evolutionary events.

the timing

Fossil data is used to align _________________with geological timelines

divergence estimates

The molecular clock method estimates the timing of evolutionary events based on ________________.

DNA mutation rates

______________ use assumptions about character evolution rates to refine phylogenies

Statistical methods

________________is the reconstruction and study of evolutionary relationships.

Systematics

_______________is the practice of placing species and groups of species such as phylums, classes, and genera into the taxonomic hierarchy.

Classification

True or false: Systematics and classification are essentially the same practice

False

A _____________________ includes the most recent common ancestor and all of its descendants.

monophyletic group

A ________________ group lacks a common ancestor

Polyphyletic

A _______________ tree excludes some descendants of a common ancestor. 

Paraphyletic

Taxonomic hierarchies are based on _____________ and should reflect evolutionary relationships.

shared traits

True or false: Established taxonomic groups do not always match new understanding of phylogenetic relationships.

True

A dolphin fin and the leg of a horse are examples of….

Homologous structures

The wings of birds and dragonflies are examples of …

Homoplastic structures

Sieve tubes would be examples of _______________since they are not derived from the same ancestral sorters.

homoplasies

In order to construct one of these diagrams, biologists collect data on the      _________________ of organisms, which are recognizable, heritable features of an organism.

characters

What refers to a shared character state that has not been inherited from a
common ancestor - can result from convergent evolution or evolutionary reversal.

Homoplasy

True or false: Genetics can help explain species diversification.

true

_________________ refers to the number of species per clade.

Species richness

Shared, derived characters—called ______________are informative in determining evolutionary relationships.

synapomorphies

Organisms that are closely related, but not direct members of the group being studied

Outgroup

An organism and all of its descendants

Clade

A point of divergence in which a lineage splits

Node

Which taxonomic groups could contain species that have similar phenotypes as a result of convergent evolution?

Polyphyletic

A _____________is a diagram that depicts evolutionary relationships among species without indicating the amount of evolutionary change.

cladogram

Only _________ __________ characters are considered informative

shared derived

The most parsimonious phylogeny is one that includes the fewest _____________ ________.

evolutionary events