IB Biology Topic B4.1.2 Adaptations of Organisms to the Abiotic Environment of Their Habitat Revision Notes (SL/HL)

IB Biology Topic B4.1.2 Adaptations of Organisms to the Abiotic Environment of Their Habitat Revision Notes (SL/HL) | RevisionDojo

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Abiotic Stress Drives the Adaptations That Let Species Survive Where Others Cannot

Definition

Abiotic factors

Abiotic factors are non-living components like temperature, water availability, salinity, and soil type.

The abiotic conditions of a habitat, such as water, salinity, temperature and oxygen, set the challenges an organism must overcome to survive and reproduce.
Over many generations, natural selection favours individuals whose inherited traits fit these conditions, so the whole population becomes adapted.
An adaptation is a feature of a population produced by this process, not a change an individual chooses to make in response to its surroundings.
Adaptations fall into three categories.
1. Structural adaptations are physical features of the body, such as specialised roots or leaves.
2. Physiological adaptations are internal chemical or cellular processes, such as excreting excess salt or storing solutes to hold water.
3. Behavioural adaptations are inherited patterns of activity, such as feeding at night to avoid daytime heat.

Note

The two worked examples below both face abiotic stress from salinity and water balance, but they solve it in very different ways.

Lyme Grass: Structural Traits That Beat Drought on Shifting Sand

Lyme grass lives on coastal sand dunes, where the sand is dry, salty, nutrient-poor and constantly shifting.
It is a xerophyte, meaning its features are adapted to reduce water loss in dry conditions.
Its key adaptations reduce water loss and keep it anchored.
1. A thick waxy cuticle cuts water loss through the leaf surface by transpiration.

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Note

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Excepteur sint occaecat cupidatat non proident

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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 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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Abiotic Stress Drives the Adaptations That Let Species Survive Where Others Cannot

Definition

Abiotic factors

Abiotic factors are non-living components like temperature, water availability, salinity, and soil type.

The abiotic conditions of a habitat, such as water, salinity, temperature and oxygen, set the challenges an organism must overcome to survive and reproduce.
Over many generations, natural selection favours individuals whose inherited traits fit these conditions, so the whole population becomes adapted.
An adaptation is a feature of a population produced by this process, not a change an individual chooses to make in response to its surroundings.
Adaptations fall into three categories.
1. Structural adaptations are physical features of the body, such as specialised roots or leaves.
2. Physiological adaptations are internal chemical or cellular processes, such as excreting excess salt or storing solutes to hold water.
3. Behavioural adaptations are inherited patterns of activity, such as feeding at night to avoid daytime heat.

Note

The two worked examples below both face abiotic stress from salinity and water balance, but they solve it in very different ways.

Lyme Grass: Structural Traits That Beat Drought on Shifting Sand

Lyme grass lives on coastal sand dunes, where the sand is dry, salty, nutrient-poor and constantly shifting.
It is a xerophyte, meaning its features are adapted to reduce water loss in dry conditions.
Its key adaptations reduce water loss and keep it anchored.
1. A thick waxy cuticle cuts water loss through the leaf surface by transpiration.

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 B4.1.2: Adaptations of Organisms to the Abiotic Environment of Their Habitat Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Abiotic Stress Drives the Adaptations That Let Species Survive Where Others Cannot

Lyme Grass: Structural Traits That Beat Drought on Shifting Sand

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

Abiotic Stress Drives the Adaptations That Let Species Survive Where Others Cannot

Lyme Grass: Structural Traits That Beat Drought on Shifting Sand

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