High School Biology : Understanding Phylogenetics

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #1 : Understanding Phylogenetics

To what domain do humans belong?

Possible Answers:

Animalia

Bacteria

Eukaryota

Archaea

Correct answer:

Eukaryota

Explanation:

Eukaryota is one of the three phylogenetic domains, with the remaining two being Bacteria and Archaea. Eukaryota contains all eukaryotic organisms, including humans. Bacteria and Archaea both contain only prokaryotic organisms, but have certain distinguishing features.

The hierarchy of phylogenetic classification is domain, kingdom, phylum, class, order, family, genus, species. There are six kingdoms: Bacteria, Archaea, Protista, Plantae, Fungi, and Animalia. Humans are in the domain Eukaryota, under the kingdom Animalia.

Example Question #581 : High School Biology

Which of the following is the correct hierarchy for classifying organisms, from most inclusive to least inclusive?

Possible Answers:

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

Animalia, Plantae, Fungi, Protista

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

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

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

Correct answer:

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

Explanation:

The most inclusive hierarchical category is domain. There are three domains, which include all forms of life: bacteria, archaea, and eukaryota. The least inclusive, and thus most specific, category is species. This means that two organisms that are the same species are more evolutionarily related than two organisms that are part of the same genus.

In order, the hierarchy of biological classification is: domain, kingdom, phylum, class, order, family, genus, species.

Example Question #582 : High School Biology

The vertex where two branches start on a phylogenetic tree most specifically represents __________.

Possible Answers:

the previous generation of a population

a common ancestor

a prey species

a new species

a similar species

Correct answer:

a common ancestor

Explanation:

The point where two branches meet on a phylogenic tree represents a species that is a common ancestor of all the "branch" species that meet at that point. The branching represents the development of new species. One thing to remember is that phylogenetic trees do not depict generations like a pedigree or family tree does.

Example Question #1 : Understanding Phylogenetics

Which of the following information could NOT be found on a phylogenetic tree (cladogram)?

Possible Answers:

Which species are descended from which other species

Common ancestors of extant species

Predator-prey relationships of extant species

How closely related various extant species are

Correct answer:

Predator-prey relationships of extant species

Explanation:

A phylogenetic tree presents data about which species developed from common ancestors. Phylogenetic trees can be used to infer how closely related various extant species are; however, phylogenetic trees do not include any data about predator-prey relationships.

Example Question #1 : Understanding Phylogenetics

Phylotree

Which characteristic is useful to infer a sister relationship (a synapomorphy) between taxa A and B?

Possible Answers:

Wings only

Feathers only

Tail, horn, and wings 

Tail only

Wings and feathers 

Correct answer:

Wings only

Explanation:

To determine a sister relationship, we need to determine a characteristic that is shared only between the two taxa A and B. Wings is the correct answer because it is the only characteristic that is shared by only taxa A and B. Feathers is a characteristic that is only present in taxon A. Tail is shared between all the taxa and horn is shared between all taxa A-E

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