IB Biology Topic A4.2.5 Evidence for a Biodiversity Crisis Revision Notes (SL/HL)

IB Biology Topic A4.2.5 Evidence for a Biodiversity Crisis Revision Notes (SL/HL) | RevisionDojo

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Biodiversity Crisis: Species Are Disappearing 100–1,000 Times Faster Than Natural Rates

The biodiversity crisis refers to the accelerated loss of species, habitats, and genetic diversity due to human activities.
Unlike natural extinction events, which occur over millennia, today's rates are extraordinary:
1. Current extinction rate: 100–1,000 times higher than the natural background rate.
2. At-risk species: Up to one million species are at risk of extinction in the coming decades.

Measuring Loss: Scientists Use Richness, Evenness, and Long-Term Monitoring

Biodiversity metrics: richness and evenness
1. Scientists measure biodiversity using two main metrics:
  1. Species richness: The total number of species in a given area.
  2. Species evenness: The distribution of individuals among those species.

Example

A coral reef with 500 fish species has high richness.
If most fish belong to one species, evenness is low.

Long-term monitoring
1. Long-term studies track changes in species populations and ecosystem health over time.

Example

Arctic fox populations are monitored annually to assess the impacts of climate change and competition with red foxes.
Amphibian populations in tropical rainforests are tracked to understand the effects of habitat loss and disease.

Note

Long-term monitoring allows scientists to identify patterns and potential causes of biodiversity loss, such as climate change, habitat destruction, and invasive species.

Global Evidence: IPBES and IUCN Data Confirm Accelerating Biodiversity Decline

The IPBES report

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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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Biodiversity Crisis: Species Are Disappearing 100–1,000 Times Faster Than Natural Rates

The biodiversity crisis refers to the accelerated loss of species, habitats, and genetic diversity due to human activities.
Unlike natural extinction events, which occur over millennia, today's rates are extraordinary:
1. Current extinction rate: 100–1,000 times higher than the natural background rate.
2. At-risk species: Up to one million species are at risk of extinction in the coming decades.

Measuring Loss: Scientists Use Richness, Evenness, and Long-Term Monitoring

Biodiversity metrics: richness and evenness
1. Scientists measure biodiversity using two main metrics:
  1. Species richness: The total number of species in a given area.
  2. Species evenness: The distribution of individuals among those species.

Example

A coral reef with 500 fish species has high richness.
If most fish belong to one species, evenness is low.

Long-term monitoring
1. Long-term studies track changes in species populations and ecosystem health over time.

Example

Arctic fox populations are monitored annually to assess the impacts of climate change and competition with red foxes.
Amphibian populations in tropical rainforests are tracked to understand the effects of habitat loss and disease.

Note

Long-term monitoring allows scientists to identify patterns and potential causes of biodiversity loss, such as climate change, habitat destruction, and invasive species.

Global Evidence: IPBES and IUCN Data Confirm Accelerating Biodiversity Decline

The IPBES report

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 A4.2.5: Evidence for a Biodiversity Crisis Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Biodiversity Crisis: Species Are Disappearing 100–1,000 Times Faster Than Natural Rates

Measuring Loss: Scientists Use Richness, Evenness, and Long-Term Monitoring

Global Evidence: IPBES and IUCN Data Confirm Accelerating Biodiversity Decline

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

Biodiversity Crisis: Species Are Disappearing 100–1,000 Times Faster Than Natural Rates

Measuring Loss: Scientists Use Richness, Evenness, and Long-Term Monitoring

Global Evidence: IPBES and IUCN Data Confirm Accelerating Biodiversity Decline

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