Classification of living organisms Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Biology — Foundation

What is biological classification based on?

Grouping organisms by their shared observable characteristics.

How does the number of shared features affect how closely organisms are grouped?

The more features they share, the more closely they are grouped.

How does biological classification help biologists?

It organises living things so they can be identified, studied and compared more easily.

What is phylogenetic classification?

The grouping of species according to their evolutionary origins and relationships.

What is a taxon, and what is its plural?

A taxon is a classification group; the plural is taxa.

How are smaller and larger taxa arranged in a classification hierarchy?

Smaller taxa are nested within larger taxa.

Can classification groups at the same rank overlap?

No, groups at the same rank do not overlap.

What are the eight taxonomic ranks, from broadest to most specific?

Domain → kingdom → phylum → class → order → family → genus → species.

What does an evolutionary tree represent?

Lineages and their branching relationships.

What does a branch point on an evolutionary tree represent?

A common ancestor from which lineages diverged.

How does the timing of a common ancestor indicate how closely related organisms are?

Organisms sharing a more recent common ancestor are more closely related.

Does an evolutionary tree imply that one living organism is the ancestor of another living organism?

No. Its arrangement does not imply that one living organism is the ancestor of another.

What features help identify what is being compared in evolutionary charts, graphs and tables?

Headings, axes, units and keys.

How can values and patterns in evolutionary charts, graphs and tables be used?

They can be extracted to compare organisms or changes over time.

When can an evolutionary tree or graph support conclusions about timing?

Only when a time scale is provided.

What is binomial nomenclature?

A system that gives each species a two-part scientific name.

What are the two parts of a species’ scientific name, and how are they capitalised?

The genus begins with a capital letter; the specific epithet begins with a lowercase letter.

How is a species’ full scientific name conventionally formatted?

It is written in italics.

Who developed binomial nomenclature?

Carl Linnaeus.

What classification system did Linnaeus develop alongside binomial nomenclature?

A hierarchical system based on shared characteristics.

Why can classification systems change?

New evidence can reveal previously unrecognised features and relationships.

How did improvements in microscopes provide evidence for classification?

They allowed internal structures to be compared in greater detail.

What biochemical advances provided further evidence for grouping organisms?

Improved understanding of biochemical processes and advances in chemical analysis.

What two types of evidence are used to construct evolutionary trees?

Classification data for living organisms and fossil data for extinct organisms.

What do evolutionary trees represent?

Inferred relationships between organisms.

When can an evolutionary tree be revised?

When further evidence becomes available.