18 classification/ taxonomy, 18.2 Flashcards
what is the classification of organisms?
Taxonomy
taxonomy
the discipline of naming and classifying organisms
who invented binomial nomenclature?
Carolus Linnaeus
binomial nomenclature
each species is assigned a two-part scientific name.
- the first part refers to the genus
genus
a group of closely related species
species consists of..
individuals who can interbreed
Linnaeus’s system of classification has seven different levels. what are they?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
what are each of the 7 levels called?
taxon
a genus is a group of…
a genus is a group of similar species
a family is a group of…
a family is a group of similar genera
what is a taxon composed of similar genera?
family
what is a taxon composed of orders?
class
compared to before, how do biologists now group organisms?
Early classifications were based on visible similarities. However, biologists now group organisms according to evolutionary relationships.
phylogeny
the study of evolutionary relationships among organisms
evolutionary classification
Method of grouping organisms together according to their evolutionary history
key points of evolutionary classification
- Species within one genus are more closely related to each other than to species in another genus because all members of a genus share a recent common ancestor
- The higher level of the taxon, the farther back in time is the common ancestor of all the organisms in that taxon.
cladistic analysis
-used to determine evolutionary relationships
what is cladistic analysis based on?
derived characteristics
derived characteristics
- Characteristics that appears in recent parts of a lineage, but not in its older members
- are new traits that arise as a group evolves over time
- Are found in closely related organisms but not in their distant ancestors
- Can be used to construct a cladogram
cladogram
a diagram that shows the evolutionary relationships among a group of organisms
do all organisms have DNA?
ALL organisms have DNA and RNA
if the molecules are similar in different species, what does that tell you?
The more similar the molecules are in different species, the more recently the species shared a common ancestor, therefore, the more closely related they are
molecular clock
a model that uses DNA comparisons to estimate the length of time that two species have been evolving independently
DNA evidence
the more similar the DNA of two species are, the more recently they shared a common ancestor, and the more closely related they are in evolutionary terms
