Classification & cladistics - biological classification Flashcards
Why is biological classification needed?
To make sense of the vast diversity of life on Earth known as global biodiversity.
What is the science of classification called?
Taxonomy.
Who are scientists working in the field of taxonomy?
Taxonomists.
What does classifying an organism involve?
Deciding which biological group, or taxon, it fits into and naming it according to its taxon.
How was an organism’s biological group historically determined?
Based on its observable characteristics.
What modern method is combined with observable characteristics for accurate classification?
Genome sequencing data.
What are the benefits of correct classification?
- Accurately determine the number of known species
- Learn about the evolution of species
- Ensure that conservation is carried out when needed
- Carry out medical research more quickly
- Identify and treat new diseases more quickly
What is the risk of not classifying species correctly?
Recording species more than once or incorrectly grouping multiple species together as one.
What is the traditional hierarchy of taxa?
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is a hierarchical system in biological classification?
A system where larger groups contain smaller groups with no overlap between groups.
What challenges arise from classifying organisms based on morphology?
Observable characteristics do not always indicate a recent common ancestor.
Give an example of organisms that could be misclassified based on morphology.
Dolphins and sharks.
What is introgression in the context of species classification?
The fertile offspring of a cross between two species breeding only with members of one parent species.
What does the term ‘taxonomic rank’ refer to?
Each level of classification in the hierarchy, such as kingdom or phylum.
Why can classification be complicated when organisms fall across taxa?
Moving a group of organisms may require shunting all groups in a taxon to a different rank.
What is a limitation of the traditional taxonomic hierarchy?
It is arbitrarily set up by humans and does not reflect natural patterns.
What does the newer system of cladistics focus on?
Unranked groups based on evolutionary relationships to produce evolutionary trees.
Fill in the blank: The point at which two populations are classified as different species can be highly _______.
[subjective]
True or False: A successful classification system should fit the natural world into a human-designed system.
False.
What does new evidence from genome sequencing often lead to?
The reclassification of species.
