Essential idea: Gene pools change over time.
The two butterfly species of the Heliconius genus above have only recently diverged and consequently differ in twelve regions of their genomes. Other species of the genus diverged earlier show hundreds of genomic changes.
http://phys.org/news/2013-10-evolution-species-requires-genetic.html
http://phys.org/news/2013-10-evolution-species-requires-genetic.html
Understandings, applications and skills
| 10.3.U1 | A gene pool consists of all the genes and their different alleles, present in an interbreeding population. |
| 10.3.U2 | Evolution requires that allele frequencies change with time in populations. |
| 10.3.U3 | Reproductive isolation of populations can be temporal, behavioural or geographic. |
| 10.3.U4 | Speciation due to divergence of isolated populations can be gradual. |
| 10.3.U5 | Speciation can occur abruptly. [Punctuated equilibrium implies long periods without appreciable change and short periods of rapid evolution. ] |
| 10.3.A1 | Identifying examples of directional, stabilizing and disruptive selection. |
| 10.3.A2 | Speciation in the genus Allium by polyploidy. |
| 10.3.S1 | Comparison of allele frequencies of geographically isolated populations. |
[Text in square brackets indicates guidance notes]
Starter
Speciation: Of Ligers & Men - another high speed introduction by Hank of Crash Course
Presentation and NotesThe presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
VocabularyCorrect use of terminology is a key skill in Biology. It is essential to use key terms correctly when communicating your understanding, particularly in assessments. Use the quizlet flashcards or other tools such as learn, scatter, space race, speller and test to help you master the vocabulary.
This quizlet is a contribution from Melissa Pain
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Weblinks
Species
What is a species? and The Idea of a species by Mark Ridley
Speciation Examples
A new species of salamander evolving in California by PBS
Anole Lizards: An Example of Speciation by HHMI
Speciation
Speciation by ZeroBio
Speciation mechanisms by W H Freeman
What is a species? and The Idea of a species by Mark Ridley
Speciation Examples
A new species of salamander evolving in California by PBS
Anole Lizards: An Example of Speciation by HHMI
Speciation
Speciation by ZeroBio
Speciation mechanisms by W H Freeman
Nature of science
Looking for patterns, trends and discrepancies—patterns of chromosome number in some genera can be explained by speciation due to polyploidy. (3.1) [linked to 10.3.A3]
Theory of knowledge
Punctuated equilibrium was long considered an alternative theory of evolution and a challenge to the long established paradigm of Darwinian gradualism. How do paradigm shifts proceed in science and what factors are involved in their success?
