Extinction Flashcards Preview

Biodiversity And Conservation > Extinction > Flashcards

Flashcards in Extinction Deck (68)
Loading flashcards...
1

Extinction in the Holocene era (10,000 years ago)

Largest ground sloth was the size of an elephant.
Claws could reach 50cm in length.
Ground sloth was nothing like other animals, tiny head, slim shoulders and massive hind quarters.
Herbivores like their modern day tree sloth predecessors.

2

What is there a long term balance between

Rates of speciation and extinction

3

How can an equilibrium species richness be predicted

Based on rates of extinction and speciation among existing species

4

How many species have evolved on earth over the last 3.5 billion years

4 billion

5

What percentage of the 4 billion species have gone

99%

6

What does the species we have today represent

A very small proportion of what has been living in the planet

7

How many mass extinctions has there been

5 so far

8

What are mass extinctions

Times when the earth loses more than three quarters of its species in a geologically short interval

9

What are the names of the extinction events

Ordovician
Devonian
Permian
Triassic
Cretaceous

10

How much did the Ordovician event lose

86%

11

How much did the Devonian event lose

75%

12

How much did the Permian event lose

96%

13

How much did the Triassic event lose

80%

14

How much did the Cretaceous event lose

76%

15

The main causes of the Ordovician event

Onset of alternating glacial and interglacial episodes

16

The main causes of the Devonian event

Global cooling followed by warming, tied to diversification of plants

17

The main causes of the Permian event

Siberian volcanism and global warming

18

The main causes of the Triassic event

Elevated co2 levels increasing temperature and ocean acidification

19

The main causes of the Cretaceous event

A meteor causing a global cataclysm and caused cooling . May have also been climate change before

20

What do mass extinctions account for

4% of total extinctions (background rate is high)

21

What do mass extinctions do

Disrupt overall development of diversity

22

What do survivors of mass extinctions tend to be

Generalists and opportunists

23

How long does it take after a mass extinction to recover biodiversity

10 million years

24

What is the lifespan of all species

1 million

25

What does the IUCN red list data say about extinction

27,000 species are threatened.
14% birds
25% mammals
40% amphibians

26

Why is speciation not a relevant time frame to ya

Because time frame for speciation isolation is longer than extinction

27

What are traits promoting survival

R-selected traits
Large populations.
Widespread.
High genetic variability.
Rapid dispersal.
Human commensalism.

28

Traits promoting extinction

K-selected traits.
Small populations.
Rare.
Low genetic variability.
Slow dispersal.
Exploited by humans.

29

What are r species

Opportunistic pioneers. They have been selected for their ability to reproduce rapidly

30

What are k species

Specialists. Have features that favour populations remaining close to the habitats carrying capacity