The Swedish naturalist Carl Linnaeus devised the hierarchical system that places each organism in a series of nested groups.
Missing Word
Linnaeus
Carl Linnaeus created the hierarchical classification system still in use and popularized two-part scientific names; later biologists added levels such as phylum, family and, in 1990, domain.
Category: Levels of Classification
Question 2
The science of naming organisms and sorting them into an internationally shared classification system is called taxonomy.
Missing Word
taxonomy
Taxonomy, a word that roughly means arrangement law, is the naming and grouping of species, and it organizes them into the Linnaean levels.
Category: Levels of Classification
Question 3
The evolutionary history of a species or group, including how it is related to other organisms, is called its phylogeny.
Missing Word
phylogeny
A phylogeny describes descent and relationships, and it is usually drawn as a phylogenetic tree that scientists treat as a hypothesis.
Category: Phylogeny and Systematics
Question 4
The group of organisms at any one level of the classification hierarchy, such as a particular family or order, is called a taxon.
Missing Word
taxon
A taxon is any named group in the classification hierarchy, from a domain down to a species. The plural form is taxa.
Category: Levels of Classification
Question 5
In binomial nomenclature, the first word of a scientific name identifies the genus.
Missing Word
genus
A scientific name has two parts: the genus name, which is capitalized, followed by the species name. Both are written in italics.
Category: Levels of Classification
Question 6
Plants, animals, fungi and protists all belong to the domain Eukarya.
Missing Word
Eukarya
Eukarya is the domain of organisms whose cells have a nucleus. The other two domains, Bacteria and Archaea, are made up of prokaryotes.
Category: Levels of Classification
Question 7
Until the 1970s all prokaryotes were grouped as bacteria, but large genetic differences led biologists to place one group in its own domain, Archaea.
Missing Word
Archaea
Archaea are prokaryotes that differ genetically from bacteria enough to form a separate domain, one of the three fundamental branches of life.
Category: Levels of Classification
Question 8
Dogs, humans and fish all belong to the phylum Chordata.
Missing Word
Chordata
Chordata is the phylum that includes all vertebrates and some close invertebrate relatives, such as lancelets. Dogs, humans and fish all fall within it.
Category: Levels of Classification
Question 9
Domestic dogs, wolves and cats are all placed in the mammal order Carnivora.
Missing Word
Carnivora
Carnivora is the order of meat-eating mammals that includes both the dog family and the cat family. The two families split below this level.
Category: Levels of Classification
Question 10
A phylogenetic tree is described as rooted when a single ancestral lineage at its base gives rise to every organism shown.
Missing Word
rooted
A rooted tree has one ancestral lineage at the base, which shows the direction of evolution from the common ancestor outward to the tips.
Category: Phylogenetic Trees
Question 11
A clade is also called a monophyletic group because it includes one ancestor and every one of its descendants.
Missing Word
monophyletic
Monophyletic means arising from a single ancestral line. A monophyletic group contains an ancestor and all of its descendants, with none left out.
Category: Cladistics
Question 12
The method that builds phylogenetic trees by grouping organisms into clades according to shared derived characters is called cladistics.
Missing Word
cladistics
Cladistics is the most widely accepted way to build phylogenetic trees. It relies on derived traits that appeared in a common ancestor and were passed to its descendants.
Category: Cladistics
Question 13
In a cladistic analysis, the ingroup is the set of taxa being studied, which are compared against a lineage that diverged earlier.
Missing Word
ingroup
The ingroup is the set of organisms whose relationships are being worked out. Comparing it with an earlier-diverging lineage shows which traits are ancestral and which are derived.
Category: Cladistics
Question 14
When building a phylogenetic tree, the direction in which a character changes, such as from a non-amniotic egg to an amniotic egg, is called polarity.
Missing Word
polarity
Polarity tells which state of a character is ancestral and which is derived, and it is determined by comparison with an earlier-diverging lineage.
Category: Cladistics
Question 15
The formal Latin name of the class that includes dogs, cats, rabbits and humans, whose members have hair and feed their young milk, is Mammalia.
Missing Word
Mammalia
Mammalia is the class of vertebrates that have hair and nourish their young with milk from mammary glands. It sits below the phylum Chordata and above orders such as Carnivora.
Category: Levels of Classification