Chapter 26: Phylogeny

Question 1

Phylogeny

Answer 1

The evolutionary history of a species or group of related species

Question 2

Systematics

Answer 2

The discipline of classifying organisms and determining their evolutionary relationships

Originial system was devised by Carolus Linnaeus in the 18th century based on resemblances

Question 3

Taxonomy

Answer 3

The scientific discipline concerned with classifying and naming organisms

Question 4

Binomial naming system

Answer 4

The first part of the name is the genus

The second part is called the specific epithet which is unique for each species within the genus

The first letter of the genus is capitalized and the entire species name is italicized

Both parts together name the species (not the specific epithet alone)

E.g., Panthera pardus is the scientific name for the leopard

Question 5

Linnaean system

Answer 5

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• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 6

Taxon

Answer 6

Named group at any given level of organization; plural is taxa

E.g., for a leopard,Panthera pardus, Panthera is the taxon at the genus level and Mammalia is the taxon at the class level

Question 7

Phylogenetic tree

Answer 7

A branching diagram that relates the evolutionary history of a group of organisms

Each branch point represents the common ancestor of the two evolutionary lineages diverging from it

An evolutionary lineage is the sequence of ancestral organisms leading to a particular descendant taxon

A basal taxon is a leneage that diverges from all other members of its group early in the history of the group such as the fish

Represents a hypothesis about evolutionary relationships

Question 8

Sister taxa

Answer 8

A group of organisms that share an immediate common ancestor that is not shared by any other group

Associated with EACH branch point in a tree as each branch point represents the common ancestor of the lineages diverging from it

Question 9

Homology

Answer 9

Phenotypic and genetic similarities due to shared ancestry

• Common forelimb bone structure in some mammals

In contrast to analogy, or analogous structures, which are similarities due to convergent evolution

• Occurs when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineages