IB Biology Topic A4.1.5 Convergent Evolution as the Origin of Analogous Structures Revision Notes (SL/HL)

IB Biology Topic A4.1.5 Convergent Evolution as the Origin of Analogous Structures Revision Notes (SL/HL) | RevisionDojo

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When Unrelated Species Solve the Same Problem, They Build Different Structures

The wings of birds and insects do the same job but differ completely in structure and origin.
Such shared solutions, reached along separate evolutionary paths, are the product of convergent evolution, and the features it produces are analogous structures.

Definition

Convergent evolution

Convergent evolution is when distantly related organisms independently evolve similar traits or behaviors to adapt to similar environments

Definition

Analogous structures

Analogous structures are anatomical features in different species that serve similar functions but do not share a common evolutionary origin.

Analogous Structures Match in Function but Not in Origin

They are similar in function, performing the same role such as flight or swimming.
They arise from unrelated ancestral structures, so they have no recent common ancestor for that feature.
They evolve separately under similar selection pressures in similar environments.

Example

Bird wings and insect wings both enable flight but evolved independently.
The streamlined bodies of dolphins (mammals) and sharks (fish) both cut drag for fast swimming.

Similar Pressures Drive Similar Adaptations in Different Lineages

Convergent evolution happens when unrelated species face the same selection pressures, the environmental challenges that favour particular traits.
Those shared pressures produce comparable adaptations even in species with distinct evolutionary histories.

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Excepteur sint occaecat cupidatat non proident

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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 ullamco laboris nisi ut aliquip ex ea commodo consequat.

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.

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When Unrelated Species Solve the Same Problem, They Build Different Structures

The wings of birds and insects do the same job but differ completely in structure and origin.
Such shared solutions, reached along separate evolutionary paths, are the product of convergent evolution, and the features it produces are analogous structures.

Definition

Convergent evolution

Convergent evolution is when distantly related organisms independently evolve similar traits or behaviors to adapt to similar environments

Definition

Analogous structures

Analogous structures are anatomical features in different species that serve similar functions but do not share a common evolutionary origin.

Analogous Structures Match in Function but Not in Origin

They are similar in function, performing the same role such as flight or swimming.
They arise from unrelated ancestral structures, so they have no recent common ancestor for that feature.
They evolve separately under similar selection pressures in similar environments.

Example

Bird wings and insect wings both enable flight but evolved independently.
The streamlined bodies of dolphins (mammals) and sharks (fish) both cut drag for fast swimming.

Similar Pressures Drive Similar Adaptations in Different Lineages

Convergent evolution happens when unrelated species face the same selection pressures, the environmental challenges that favour particular traits.
Those shared pressures produce comparable adaptations even in species with distinct evolutionary histories.

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

Note

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.

Excepteur sint occaecat cupidatat non proident

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 A4.1.5: Convergent Evolution as the Origin of Analogous Structures Notes

When Unrelated Species Solve the Same Problem, They Build Different Structures

Analogous Structures Match in Function but Not in Origin

Similar Pressures Drive Similar Adaptations in Different Lineages

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

When Unrelated Species Solve the Same Problem, They Build Different Structures

Analogous Structures Match in Function but Not in Origin

Similar Pressures Drive Similar Adaptations in Different Lineages

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

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics