L5 Speciation10-11 - Lecture 5: Speciation Species and...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Lecture 5: Speciation Species and Speciation How are new species formed • models of speciation • examples What is a species? • biological species concept • phylogenetic species concept Speciation Speciation – formation of new species from pre-existing species – occurs at branching events in a phylogeny 1 2 3 4 Speciation Modes of Speciation 1. Allopatric l other place z Populations become separated by a physical barrier and then evolve reproductive barriers outlined by Ernst Mayr most common mode of speciation two types: vicariant speciation & peripatric Modes of Speciation First type of Allopatric Speciation - Vicariant Speciation : • population is divided into two widespread populations by a physical barrier e.g. Changes in courses of rivers, Mountain- building events, Volcanism, Glaciation Environmental changes Allopatric Speciation: Vicariance Geographic Separation Time
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Allopatric Speciation: Vicariance Example: freshwater fish species Allopatric Speciation: Vicariance Example: Snapping Shrimp Separation of Snapping Shrimp on either side of the Isthmus of Panama. Snapping Shrimp in Pacific and Caribbean. Allopatric Speciation: Vicariance Fig 16.8 Modes of Speciation Second type of Allopatric Speciation: Peripatric Speciation : • a small colon disperses from a widespread population to a new area and evolves reproductive isolation • Genetic drift argued as major factor in differentiating the new, small colony from parent population possibly as founder effect . Allopatric Speciation: Peripatric Speciation Geographic Separation Time localized colony diverges Allopatric Speciation: Peripatric Speciation Example: Hawaiian fruit flies D. planitibia D. silvestris D. heteroneura Fig 16.7
Background image of page 2
3 Allopatric Speciation
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

L5 Speciation10-11 - Lecture 5: Speciation Species and...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online