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ENVIRO & ECOLOGY > Extinction > Flashcards

Extinction Flashcards

1
Q

Define extinction

A

Then end of a species or group of taxa

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2
Q

what is the difference between background extinction and mass extinction

A

Background = a continual, natural process

Mass = an accelerated rate of extinction that sharply reduces the Earth’s biodiversity

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3
Q

Define extinct in the wild

A

When individuals of a species only exist in captivity

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4
Q

Define locally extinct

A

When a species/ taxon is no longer present in an area previously inhabited

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5
Q

Define ecologically extinct

A

Species found in low numbers in a community so that they now have little impact on the ecology of a habitat

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6
Q

Define extirpation

A

the disappearance of a particular population, but not the entire species globally

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7
Q

What is the average rate of background extinction

A

Between 2-10 million years (average = 4)

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8
Q

When is extinction classed as mass extinction

A

at times when the earth loses more than ¾ of its species in a geologically short interval

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9
Q

How many mass extinctions has there been?

A

5

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10
Q

Name the 5 mass extinctions

A 
Ordovician
Devonian
Permian
Triassic
Cretaceous
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11
Q

Which was the most famous mass extinction and why

A

Cretaceous - the extinction of the dinosaurs

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12
Q

Which extinction was the biggest?

A

Permian - over 95% of marine and 50% of all families globally were extinct

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13
Q

What likely caused the Permian extinction?

A

A massive perturbation (disturbance)

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14
Q

Name 3 types of species more likely to go extinct

A 
Any from:
Higher tropic levels
Endemic species
Specialists
Migratory species
Poor dispersers 
Smaller populations
Species with complex lifecycles
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15
Q

Why are endemic species more at risk of extinction

A

Because they have limited/ restrictive distributions and geographic ranges meaning they are vulnerable to disturbance of those areas

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16
Q

Why are smaller populations more vulnerable to extinction?

A 
Because they have less genetic variation in gene pools
Leads to inbreeding
Extinction vortex (pop. gets smaller = less genetic variation = smaller population)
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17
Q

What is an extinction vortex

A

the forces affecting small populations that cause them to spiral into a vortex of increasingly smaller populations and endanger their long-term survival

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18
Q

Which particular type of species has the most damaging affect on an ecosystem if lost

A

Key stone species

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19
Q

Name 3 extinct species

A 
Stellas sea cow (1768)
Great Auk (1844)
Tasmanian Tiger (1933)
Baji river dolphin (2006)
Moa (1642)
Dodo (1681)
Passenger pigeon (1914)
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20
Q

What happened to the passenger pigeon?

A

There was 3-5 billion in mid 1800s (abundant)
Hunted to extinction
Extinct by 1914

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21
Q

Why were the passenger pigeons vulnerable to extinction?

A

They had complex lifecycles - needed to rest and raise chicks around lots of other pigeons – when numbers began to decline, they could no longer breed properly

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22
Q

What 2 main reasons cause species to go extinct

A

Disturbances

Small populations die out

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23
Q

Name 5 human causes of extinction

A 
Habitat destruction and fragmentation
Climate change
Pollution
Over exploitation 
Introduced/ alien species
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24
Q

Which anagram can help remember the human causes of extinction?

A

HIPPO

Habitat destruction
Introduced species
Pollution
Population 
Overexploitation
25
Q

What is the evil quartet?

A

Habitat destruction
Introduced species
Chains of extinction
Overkill

26
Q

Define chains of extinction

A

When the extinction of one species caused by the extinction or decline of another species on which the first depends

27
Q

Name 4 human causes of habitat destruction

A 
Agriculture
Urban development
Deforestation
Pollution
Climate change
28
Q

Which human factor do IUCN is the biggest threat to species?

A

Habitat destruction

29
Q

Define relaxation

A

The loss of species from isolated habitats over time

30
Q

Give 4 examples of endangered species on the IUCN list

A 
Any from:
Hawksbill turtles
Golden Lion Tamarins 
Black Rhino (is increasing)
Asian Elephant
Rusty Patched Bumble Bee
Malayan Tiger
Pygmy three-toed sloth 
Mongoose Lemur 
Sunflower Seastar
31
Q

What causes relaxation?

A

Fragmentation
Isolation
The separation of islands from mainland

32
Q

What are edge effects

A

negative impacts adjacent to habitat boundaries

33
Q

Which effect is caused by fragmentation

A

Edge effects

34
Q

What is one human cause of invasive species?

A

Ship ballast water

35
Q

Give 3 reasons forest edges make species more vulnerable

A 
More sunlight
Dryer
Higher winds
Less protection
More predation
Invasive species from outside the habitat
36
Q

Which type of habitat will invasive species affect most negatively?

A

Isolated islands

37
Q

Which case study if invasive species is known as Darwin’s Nightmare

A

Nile Perch, 1954

38
Q

What happened in Lake Victoria in 1954 with Nile perch

A

Nile perch fish were introduced into lake victoria for human food
Perch annihilated the cichlid population
cichlids lacked defensive adaptations
Perch then had nothing to feed on and declined so couldn’t be used as a human food source

39
Q

Which is a case study for invasive species through ship ballast water

A

Chinese Mitten crab

40
Q

why are invasive species so successful?

A

Have no diseases, parasites or predators in the new area
They are usually better competitors than native species
They prey on vulnerable native species that lack defensive adaptions

41
Q

Which 2 features of species make them the most vulnerable to exploitation?

A

K selected species

Species with restricted habitats (i.e: islands)

42
Q

What are k selected species

A

those that possess relatively stable populations that fluctuate near the carrying capacity - they usually only have a few offspring and invest high amounts of parental care

43
Q

Name 3 K selected species

A

Sharks
Elephants
Humans
bison

44
Q

What is bycatch

A

The non-targeted species killed in fisheries

45
Q

What is bush meat

A

harvest of wild animals for food

46
Q

Which industry is worst for overexploitation?

A

Fisheries

47
Q

What is another industry of overexploitation besides fisheries

A

Global trade - i.e: pets, plants, bekko, ivory, fashion

48
Q

Which type of environment does pollution most effect?

A

Aquatic

49
Q

What is bioaccumulation

A

process by which toxins concentrations increase in living tissues

50
Q

Why is bioaccumulation so damaging to food chains?

A

concentrations increase through the food chain

51
Q

Give 2 examples of bioaccumulation

A

Methylmercury

DDT (an insecticide)

52
Q

What are endocrine disruptors?

A

chemicals/ compounds that interfere with the hormonal systems

53
Q

Which threat causes endocrine disruptors?

A

Pollution - particularly chemical pollutants in aquatic systems

54
Q

Name 2 examples of endocrine disruptors

A

TBT (Tributyltin) - anti-fouling paint on boats

Xenoestrogens - birth control

55
Q

How do xenoestrogens affect marine species?

A

Causes freshwater fish to become intersex - effects reproductive rates

56
Q

How does TBT (tributyltin) affect marine invertebrates?

A

Causes marine invertebrates to become imposex (i.e: dogwhelk females develop male genetalia)

57
Q

What are the 4 types of genetic effects that can cause vulnerability in a species?

A

Bottlenecking
Inbreeding
Genetic Drift
Random Mutation

58
Q

Why does a lack of genetic variation cause vulnerability?

A

Less genetic variation means less ability to adapt to environmental changes - so when a disturbance event occurs, a species cannot adapt (well) to survive it

ENVIRO & ECOLOGY (24 decks)

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