Species Concepts

Question 1

What is a species concept?

Answer 1

A species concept is a set of ideas about what key elements of biodiversity should represent or reflect. It serves as a framework to define species.

Question 2

How many species concepts have been proposed?

Answer 2

At least 25-35 different species concepts have been proposed, discussed, and debated.

Question 3

Why might different subdisciplines of biology need different species concepts?

Answer 3

They may require concepts that emphasize specific methods of identifying or analyzing species relevant to their research.

Question 4

What fundamental differences might lead to varied species concepts?

Answer 4

Differences in the questions biologists ask about the natural world and the organisms they study.

Question 5

How can the type of organism being studied influence species concepts?

Answer 5

Biologists working with different organisms might need to prioritize different types of information or criteria.

Question 6

What is the extreme perspective on species naming?

Answer 6

Species are seen as human-made constructs for convenience, though there are real natural discontinuities.

Question 7

What is the cryptic species concept?

Answer 7

It highlights cases where species look similar but differ based on behavior, morphology, or genetics.

Question 8

How do species names help us predict properties?

Answer 8

Species names indicate shared traits and histories, e.g., Drosophila melanogaster has eight chromosomes.

Question 9

What does naming species signal about their current properties?

Answer 9

It suggests behaviors or capabilities, e.g., Mus musculus individuals can interbreed.

Question 10

What does evolutionary biology emphasize in species concepts?

Answer 10

Evolutionary processes and speciation are central to species definitions.

Question 11

Why is naming species valuable in biology?

Answer 11

It provides information about the expected properties of individuals sharing the same name.

Question 12

What are the three basic categories of species concepts?

Answer 12

Reproductive community (e.g., Biological Species Concept), genealogical group (e.g., Phylogenetic Species Concept), and trait-sharing cluster (e.g., Ecological Species Concept).

Question 13

What traits do most species concepts share?

Answer 13

They describe units consistent with the existence of reproductive communities

Question 14

What does the Biological Species Concept emphasize?

Answer 14

Reproductive isolation and barriers that prevent or reduce gene flow between populations.

Question 15

Why is the BSC favored by speciation biologists?

Answer 15

It provides clear criteria for identifying ‘good species’ based on gene flow and reproductive isolation.

Question 16

What challenges does the BSC face?

Answer 16

Defining species when populations are geographically separated (potential vs. actual interbreeding).

Determining whether absolute reproductive isolation is necessary.

Handling cases of occasional hybridization

Question 17

What is the focus of the PSC?

Answer 17

Monophyly and evolutionary lineage, identifying species at the tips of the tree of life.

Question 18

What are the advantages of the PSC?

Answer 18

It applies to sexual/asexual groups, fossil taxa, and provides clear criteria.

Question 19

What challenges does the PSC face?

Answer 19

Defining levels of monophyly, determining useful genetic markers, and addressing incomplete sampling in phylogenetic trees.

Question 20

What does the GCSC use to define species?

Answer 20

Distinct clusters of genotypes with gaps in possible multilocus genotypes.

Question 21

How does the GCSC handle gene flow?

Answer 21

It does not require gene flow to stop entirely; it identifies distinct phenotypic or genetic clusters instead.

Question 22

What are strengths of the GCSC?

Answer 22

Utilizes population genetics and genomic data, and accounts for distinct gene pools despite potential gene flow.

Question 23

What challenges face the GCSC?

Answer 23

Defining levels of differentiation and handling asexual lineages.

Question 24

How does the EcSC define species?

Answer 24

As lineages occupying distinct ecological niches and evolving separately.

Question 25

What are advantages of the EcSC?

Answer 25

Applicability to sexual/asexual groups and recognition of ecological adaptation in limiting gene flow.

Question 26

What are EcSC challenges?

Answer 26

Determining how distinct niches must be to define separate species.

Question 27

What is the RRCC?

Answer 27

A concept viewing reproductive communities retrospectively, focusing on cohesive processes over time.

Question 28

How does the RRCC differ from the BSC?

Answer 28

It emphasizes processes of the past, not just present reproductive isolation.

Question 29

Why is a retrospective approach important?

Answer 29

It explains present characteristics based on historical processes and evolutionary trajectories.

Question 30

What are the main goals of taxonomy?

Answer 30

To catalog Earth’s biodiversity.

To classify species for information storage and retrieval.

To understand the history and processes of biodiversity generation.

Question 31

What steps are involved in making a new species ‘official’?

Answer 31

Naming the species.

Writing a detailed species description.

Publishing the description following established rules.

Waiting for acceptance by the scientific community