IB Environmental systems and societies (ESS) - Old Topic 3.2B Invasive Species Notes & Questions (SL/HL)

IB Environmental systems and societies (ESS) - Old Topic 3.2B Invasive Species Notes & Questions (SL/HL) | RevisionDojo

Written by official IB examiners

Invasive Species: How Non-Natives Overrun Ecosystems

Definition

Invasive species

Invasive alien species are non-native organisms that, when introduced to a new ecosystem, can cause significant harm to local biodiversity.

Invasive alien species (IAS) are non-native organisms that spread and cause harm in an ecosystem where they do not naturally occur.
They can outcompete native organisms, disrupt food webs, and drive native species toward decline or extinction.
Native species are vulnerable because they never co-evolved with the newcomer and lack defences against it.

Common Mistake

Do not assume every alien species becomes invasive.
Only a small proportion establish and spread enough to become ecologically disruptive.

How Alien Species Arrive: Accidental or Deliberate

Accidental introductions
1. Global trade moves seeds, insects, and larvae in cargo, packaging, and ship ballast water.
2. Travel and tourism carry seeds stuck to shoes, clothing, and luggage.
3. Agricultural contamination brings pests and weeds in crop soil or livestock feed.
Deliberate introductions
1. Biological control releases a species to control a pest, such as cane toads in Australia.
2. Ornamental and commercial use brings in plants like Japanese knotweed and animals for aquaculture.
3. Recreation and hunting stock non-native fish, birds, or mammals for sport.

Example

Japanese knotweed was brought to Europe as a garden ornamental and now spreads uncontrollably.

Why Invasive Species Succeed: No Predators, Fast Breeding

They face no natural predators or diseases in the new ecosystem.
They reproduce quickly and in large numbers.
Their generalist diet lets them eat many different food sources.

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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

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.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

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

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

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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Invasive Species: How Non-Natives Overrun Ecosystems

Definition

Invasive species

Invasive alien species are non-native organisms that, when introduced to a new ecosystem, can cause significant harm to local biodiversity.

Invasive alien species (IAS) are non-native organisms that spread and cause harm in an ecosystem where they do not naturally occur.
They can outcompete native organisms, disrupt food webs, and drive native species toward decline or extinction.
Native species are vulnerable because they never co-evolved with the newcomer and lack defences against it.

Common Mistake

Do not assume every alien species becomes invasive.
Only a small proportion establish and spread enough to become ecologically disruptive.

How Alien Species Arrive: Accidental or Deliberate

Accidental introductions
1. Global trade moves seeds, insects, and larvae in cargo, packaging, and ship ballast water.
2. Travel and tourism carry seeds stuck to shoes, clothing, and luggage.
3. Agricultural contamination brings pests and weeds in crop soil or livestock feed.
Deliberate introductions
1. Biological control releases a species to control a pest, such as cane toads in Australia.
2. Ornamental and commercial use brings in plants like Japanese knotweed and animals for aquaculture.
3. Recreation and hunting stock non-native fish, birds, or mammals for sport.

Example

Japanese knotweed was brought to Europe as a garden ornamental and now spreads uncontrollably.

Why Invasive Species Succeed: No Predators, Fast Breeding

They face no natural predators or diseases in the new ecosystem.
They reproduce quickly and in large numbers.
Their generalist diet lets them eat many different food sources.

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.

IB Environmental systems and societies (ESS) - Old 3.2B Invasive Species Notes

Invasive Species: How Non-Natives Overrun Ecosystems

How Alien Species Arrive: Accidental or Deliberate

Why Invasive Species Succeed: No Predators, Fast Breeding

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

Invasive Species: How Non-Natives Overrun Ecosystems

How Alien Species Arrive: Accidental or Deliberate

Why Invasive Species Succeed: No Predators, Fast Breeding

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