Lesson 7: What is a Species?

Question 1

Who is Carl Linnaeus?

Answer 1

Introduced a new system for scientifically naming organisms. Linnaeus is considered to be the founding father of modern taxonomy.

Question 2

What is taxonomy?

Answer 2

Taxonomy is the science of naming and organizing organisms into related groups.

Question 3

The binomial name of a species consists of two parts: the ___ name, or generic name, and the specific ___.

Answer 3

Genus and epithet.

Question 4

What are some rules governing a binomial name?

Answer 4

1. The genus name is always capitalized and that the specific epithet is not.
2. A binomial name is always italicized.
3. Same genus means closely related, but epithet do not necessarily.
4. Rule of priority (cannot rename once official, unless mistake made).
5. Publish a description of the species in a widely distributed and peer-reviewed scientific publication and must designate a holotype specimen. The published description must include a list of characteristics or combination of characteristics that makes the new species unique.

Question 5

What is a peer-reviewed scientific publication?

Answer 5

A peer-reviewed scientific publication is one that is not published until it has been reviewed by other scientists to verify that the contents of the publication are legitimate and scientifically reasonable.

Question 6

What is a holotype specimen?

Answer 6

A holotype specimen is a physical example of the new species, and it must be kept in a research institution, such as a university or a museum, so that other scientists may study it and be able to both verify that it is a distinct species and compare it to other potentially new species that are later discovered. It does not necessarily need to be a complete specimen (a broken or partial specimen will do, as long as it shows the unique characters that make it a distinct species).

Question 7

What is an example of a holotype specimen housed at the UofA?

Answer 7

Specimen (UALVP 48778) of a small dinosaur called Hesperonychus elizabethae. UALVP 48778 includes only a partial pelvis, but this pelvis provided enough information for palaeontologists to determine that it represented a new kind of dromaeosaurid theropod.

Question 8

What is interspecific variation?

Answer 8

Individuals that differ in morphology because they belong to different species.

Question 9

What is intraspecific variation?

Answer 9

Individuals that belong to the same species, but that have different morphologies. I.e. sexual dimorphism, ontogenetic variation, and individual variation.

Question 10

What is sexual dimorphism?

Answer 10

Males and females of the same species can look different. I.e. male deer have antlers, female do not.

Question 11

What is ontogenetic variation?

Answer 11

Ontogenetic variation is the variation that you can see between young individuals and old individuals of the same species. Besides size differences, animals can change shape as they progress through ontogeny, which is a fancy way of saying ‘as they grow up’. Puppies often have shorter snouts relative to their overall head size, compared to fully grown dogs.

Question 12

What is individual variation?

Answer 12

Individual variation is the normal variation that exists among individuals of a given species. I.e. hair colour.

Question 13

What is taphonomic variation?

Answer 13

Geological: taphonomic processes like plastic deformation can change the shape of a bone, resulting in taphonomic variation.

Question 14

What is the biological species concept?

Answer 14

Defines a species as a group of organisms that can successfully interbreed.

Question 15

This species concept works well when applied to most modern animals and many plants. What are the drawbacks of the biological species concept?

Answer 15

It cannot be applied to the majority of those modern organisms that reproduce asexually and which, therefore, cannot be said to interbreed at all. Nor can the biological species concept be applied to extinct organisms of any kind, since testing whether or not two fossils can mate is impossible. Also does not account for geographical barriers.

Question 16

What is a population?

Answer 16

A population is any grouping of organisms that live in the same geographic area and interbreed.

Question 17

One or more ___ make up a single species.

Answer 17

Populations.

Question 18

What is the morphological species concept?

Answer 18

Defines a species as a group of organisms that share a certain degree of physical similarity.

Question 19

In dinosaur paleontology, the morphological species concept is often applied as it relates to the biological species concept. What are some drawbacks of the morphological species concept?

Answer 19

It is difficult to account for intraspecific variation.

Question 20

What are lumpers?

Answer 20

Paleontologists who require more differences before they consider two species to be distinct.

Question 21

What are splitters?

Answer 21

Paleontologists who require fewer differences before they consider two species to be distinct.

Question 22

Hesperonychus is one of the smallest known dinosaurs from North America. How did paleontologists know that it was a new species, rather than an individual of an already named species?

Answer 22

• several unique features on the pelvis that were not seen in any other dromaeosaurid theropod, which suggests that it was a new species.
• the bones of the pelvis were tightly fused together. In juveniles, the bones of the skull, vertebrae, and pelvis are not tightly fused together, and you can see the sutures between individual bones. The sutures were not visible in the Hesperonychus pelvis, suggesting that it was a fully-grown individual that had a small adult size.
• sexual dimorphism is harder to test, but none of the differences in the pelvis seemed likely to relate to sex-specific functions.
• the pelvis was well preserved, and taphonomic deformation could not have produced the unique features.