IB Environmental systems and societies Topic 3.1G Earth History and the Anthropocene Revision Notes (HL)

IB Environmental systems and societies Topic 3.1G Earth History and the Anthropocene Revision Notes (HL) | RevisionDojo

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Evidence of Evolution in the Rock Record

Earth is about 4.5 billion years old, and life has evolved gradually over that time.
Geological, climatic, and biological changes over millions of years shaped both the planet and its life.

The Fossil Record

Definition

Fossils

Fossils are preserved remains, traces, or imprints of ancient organisms found in sedimentary rocks.

Fossils are preserved remains in sedimentary rock, and their layers trace how species changed over time.
Transitional fossils capture the shift from one group of organisms to another.

Example

Archaeopteryx shows a mix of reptile and bird features, capturing the reptile-to-bird transition.

Homologous Structures

Related species share the same underlying body plan, inherited from a common ancestor.
The pentadactyl (five-digit) limb is a classic example of divergent evolution.

Example

Whale flippers, bat wings, and human hands share the same pentadactyl bone pattern, evidence of common ancestry.

Dating the Past

Carbon-14 dating measures radioactive decay to date relatively recent organic remains.
Ice cores trap ancient air, linking past atmospheres to climate and biodiversity.

The Geological Time Scale

Earth's history is divided into eons, eras, periods, epochs, and ages.
These divisions are defined by major biological and environmental changes, identified from fossils and radiometric dating.

The Four Great Eras of Life

Precambrian (4.6 billion – 541 million years ago)
1. Formation of Earth and the earliest, mostly single-celled life.
2. Cyanobacteria drove the Great Oxidation Event, which built the ozone layer and enabled complex life.
Paleozoic (541 – 252 million years ago)
1. The Cambrian Explosion produced rapid marine diversification; plants and amphibians colonised land.

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Evidence of Evolution in the Rock Record

Earth is about 4.5 billion years old, and life has evolved gradually over that time.
Geological, climatic, and biological changes over millions of years shaped both the planet and its life.

The Fossil Record

Definition

Fossils

Fossils are preserved remains, traces, or imprints of ancient organisms found in sedimentary rocks.

Fossils are preserved remains in sedimentary rock, and their layers trace how species changed over time.
Transitional fossils capture the shift from one group of organisms to another.

Example

Archaeopteryx shows a mix of reptile and bird features, capturing the reptile-to-bird transition.

Homologous Structures

Related species share the same underlying body plan, inherited from a common ancestor.
The pentadactyl (five-digit) limb is a classic example of divergent evolution.

Example

Whale flippers, bat wings, and human hands share the same pentadactyl bone pattern, evidence of common ancestry.

Dating the Past

Carbon-14 dating measures radioactive decay to date relatively recent organic remains.
Ice cores trap ancient air, linking past atmospheres to climate and biodiversity.

The Geological Time Scale

Earth's history is divided into eons, eras, periods, epochs, and ages.
These divisions are defined by major biological and environmental changes, identified from fossils and radiometric dating.

The Four Great Eras of Life

Precambrian (4.6 billion – 541 million years ago)
1. Formation of Earth and the earliest, mostly single-celled life.
2. Cyanobacteria drove the Great Oxidation Event, which built the ozone layer and enabled complex life.
Paleozoic (541 – 252 million years ago)
1. The Cambrian Explosion produced rapid marine diversification; plants and amphibians colonised land.

Definition

Paywall

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

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Duis aute irure dolor in reprehenderit

Note

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Excepteur sint occaecat cupidatat non proident

Tip

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Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

IB Environmental systems and societies 3.1G Earth History and the Anthropocene Notes

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

Evidence of Evolution in the Rock Record

The Fossil Record

Homologous Structures

Dating the Past

The Geological Time Scale

The Four Great Eras of Life

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Duis aute irure dolor in reprehenderit

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Evidence of Evolution in the Rock Record

The Fossil Record

Homologous Structures

Dating the Past

The Geological Time Scale

The Four Great Eras of Life

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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