What is a Species? Flashcards
(21 cards)
Carl Linnaeus
Founding father of taxonomy.
Introduced binomial naming system.
Taxonomy
Science of naming & organizing organisms into groups.
Binomial Name
Two parts: ‘Genus’ ‘Specific Epithet’
> Genus Name = Generic / Family Name (i.e. Tyrannosaurus or Chasmosaurus)
> Specific Epithet = Unique identifier to this species (i.e. rex or belli)
Rules for writing Binomial Name
- Binomial name is ALWAYS italicized
- Genus is ALWAYS capitalized
- Specific Epithet is NEVER capitalized
Rules for making Binomial Name
- Organisms that belong to same Genus (very similar in overall form, closer to e/o than any other Genus) have the same Genus name.
- Specific Epithets can be shared (when dif Genus).
- Specific combo of Genus name and Specific Epithet CANNOT be shared by any two species.
- Rule of Priority
Rule of Priority
Once a species has officially been given a binomial name, the name cannot be changed.
(UNLESS it a) turns out to not be a new species, or b) was accidentally already an existing name)
What is necessary for a Binomial name to be official?
A Biologist must publish a description of the species in a widely distributed & peer-reviewed journal, & have a designated holotype specimen.
What does the description of a new species entail?
Must include a list or combo of characteristics that makes the new species unique.
Peer-Reviewed
Won’t be published until it has been reviewed by other scientists / experts who can verify that the contents are legit & scientifically reasonable.
Holotype Specimen
Physical example of the new species.
Must be kept in a research institution (i.e. uni or museum), available to be studied, verified & compared to. Does not need to be complete specimen, just enough to show unique characteristics.
What is an example of a holotype specimen?
U of A has a holotype - UALVP 48778.
It is of Hesperonychus elizabethae. It’s a partial pelvis of this dromaeosaurid theropod. Published in ‘Proceedings of national Academy of Sciences’.
INTERspecific variation
Individuals differ in morphology because they belong to DIFFERENT species.
INTRAspecific variation
Individuals belong to the same species, but have different morphologies.
Potential sources of INTRAspecific variation
- Sexual Dimorphism - sexual variation / sex differences.
- Ontogenetic variation - variation between young & old individuals of the same species.
- Individual variation - Normal variation that exists among individuals of a given species.
- Taphonomic variation - when taphonomic processes (like plastic deformation) change shape of a bone.
Biological Species Concept
Defines a species as a group of organisms that can successfully interbreed.
Issues with Biological Species Concept
Cannot apply to majority of modern organisms that reproduce asexually.
Cannot be applied to extinct animals, as we cannot test whether 2 fossils can mate.
Population
Grouping of organisms that live in the same geographic area & interbreed.
One or more populations make up a single species.
Morphological Species Concept
Defines a species as a group of organisms that share a certain degree of physical similarity.
Often applied w/ the assumption of interbreeding by paleontologists (if reasonable / possible).
Lumpers
Paleontologists who require more differences before they consider two species to be distinct.
Splitters
Paleontologists who require fewer differences before they consider two species to be distinct.
What led us to reasonably conclude Hesperonychus elizabethae was reasonably distinct as a species?
- Had several unique features on pelvis not seen in other dromaeosaurid theropods.
- Bones of pelvis were tightly fused together, suggests fully grown adult had small adult size.
- Pelvic differences didn’t seem to relate to sex-specific functions, nor did the pelvis seem deformed (was well-preserved).
