IB Biology Topic A4.1.11 Abrupt Speciation in Plants by Hybridization and Polyploidy Revision Notes (HL)

IB Biology Topic A4.1.11 Abrupt Speciation in Plants by Hybridization and Polyploidy Revision Notes (HL) | RevisionDojo

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Hybridization Plus Chromosome Doubling Can Make a New Plant Species in One Generation

Hybridization (breeding between two species) combined with polyploidy (whole extra sets of chromosomes) can produce abrupt speciation, where a new species appears in a single generation.
This contrasts with gradual speciation, which takes many generations of allele-frequency change.
It is a major source of biodiversity in plants and has been used in agriculture to create new crops.

A Fresh Interspecific Hybrid Is Usually Sterile

Definition

Hybridization

Hybridization occurs when two distinct species interbreed, producing offspring with genetic contributions from both parents.

A hybrid between two species carries one chromosome set from each parent, and these sets do not match.
In meiosis the chromosomes cannot form homologous pairs, so functional gametes do not form and the hybrid is sterile.
This is why a doubling of the chromosome number is needed before the hybrid can breed; the full barrier taxonomy is covered in A4.1.10.

Example

The knotweed Persicaria maculosa likely arose from a hybrid between Persicaria foliosa and Persicaria lapathifolia.
The first hybrid combined traits from both parents but was sterile until chromosome doubling restored fertility.

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Hybridization Plus Chromosome Doubling Can Make a New Plant Species in One Generation

Hybridization (breeding between two species) combined with polyploidy (whole extra sets of chromosomes) can produce abrupt speciation, where a new species appears in a single generation.
This contrasts with gradual speciation, which takes many generations of allele-frequency change.
It is a major source of biodiversity in plants and has been used in agriculture to create new crops.

A Fresh Interspecific Hybrid Is Usually Sterile

Definition

Hybridization

Hybridization occurs when two distinct species interbreed, producing offspring with genetic contributions from both parents.

A hybrid between two species carries one chromosome set from each parent, and these sets do not match.
In meiosis the chromosomes cannot form homologous pairs, so functional gametes do not form and the hybrid is sterile.
This is why a doubling of the chromosome number is needed before the hybrid can breed; the full barrier taxonomy is covered in A4.1.10.

Example

The knotweed Persicaria maculosa likely arose from a hybrid between Persicaria foliosa and Persicaria lapathifolia.
The first hybrid combined traits from both parents but was sterile until chromosome doubling restored fertility.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

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Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

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Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic A4.1.11: Abrupt Speciation in Plants by Hybridization and Polyploidy Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Hybridization Plus Chromosome Doubling Can Make a New Plant Species in One Generation

A Fresh Interspecific Hybrid Is Usually Sterile

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Hybridization Plus Chromosome Doubling Can Make a New Plant Species in One Generation

A Fresh Interspecific Hybrid Is Usually Sterile

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account