Sister taxa

Definition

Sister taxa are groups of organisms that share an immediate common ancestor and are each other's closest relatives. They appear as two branches stemming from the same node on a phylogenetic tree.

5 Must Know Facts For Your Next Test

1. Sister taxa help demonstrate evolutionary relationships between different species.
2. They can be used to infer traits of a common ancestor.
3. Sister taxa are identified by locating nodes where two lineages diverge on a phylogenetic tree.
4. The concept is essential for understanding speciation events and lineage divergence.
5. Comparing sister taxa can reveal adaptive changes in response to environmental pressures.

Review Questions

• What is the significance of sister taxa in evolutionary biology?
• How are sister taxa represented on a phylogenetic tree?
• What can studying sister taxa tell us about their common ancestor?

Related terms

Phylogenetic Tree: A diagram that represents evolutionary relationships among various biological species based upon similarities and differences in their physical or genetic characteristics.

Common Ancestor: The most recent ancestral form or species from which two different species evolved.

Speciation: The formation of new and distinct species in the course of evolution, often represented by branching points on a phylogenetic tree.