IB Biology Topic A2.3.5 Evidence for Several Origins of Viruses from Other Organisms Revision Notes (HL)

IB Biology Topic A2.3.5 Evidence for Several Origins of Viruses from Other Organisms Revision Notes (HL) | RevisionDojo

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There's Evidence for Multiple Origins of Viruses

Viruses show enormous diversity in structure and genetic composition.
This diversity suggests that viruses did not arise from a single common ancestor but instead evolved multiple times from different cellular origins.
Their shared features likely result from convergent evolution, not shared descent.

Note

The genetic code is shared by viruses and cells, which suggests viruses evolved from cellular life, not before it.

Two Hypotheses: How Viruses May Have Arisen

Progressive (Escape) Hypothesis:
1. Viruses may have evolved from mobile genetic elements, like retrotransposons, which move within genomes.
2. Retrotransposons and retroviruses (e.g., HIV) both use reverse transcription, where RNA is converted into DNA.

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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.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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There's Evidence for Multiple Origins of Viruses

Viruses show enormous diversity in structure and genetic composition.
This diversity suggests that viruses did not arise from a single common ancestor but instead evolved multiple times from different cellular origins.
Their shared features likely result from convergent evolution, not shared descent.

Note

The genetic code is shared by viruses and cells, which suggests viruses evolved from cellular life, not before it.

Two Hypotheses: How Viruses May Have Arisen

Progressive (Escape) Hypothesis:
1. Viruses may have evolved from mobile genetic elements, like retrotransposons, which move within genomes.
2. Retrotransposons and retroviruses (e.g., HIV) both use reverse transcription, where RNA is converted into DNA.

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 A2.3.5: Evidence for Several Origins of Viruses from Other Organisms Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

There's Evidence for Multiple Origins of Viruses

Two Hypotheses: How Viruses May Have Arisen

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

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There's Evidence for Multiple Origins of Viruses

Two Hypotheses: How Viruses May Have Arisen

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