Lecture 16

Question 1

What are the facts about extinction gone over in class?

Answer 1

• About 1 in a thousand species that ever lives is still alive
• 99.9% of all species that ever lived are extinct today

Question 2

How big have most extinctions been?

Answer 2

small

Question 3

What are the consequences of mass extinctions?

Answer 3

• Rebounds from mass extinctions take a long time- on the order of tens of millions of years
• Extinction promotes replacement- lineages that dominate before extinction are often replaced by others

Question 4

Are replacements predictable?

Answer 4

No, not predictable before the extinction

Question 5

What is the Extinction Process?

Answer 5

Extinction of a species or population happens when the mortality rate is greater than birth rate for a sufficient length of time so that population size reaches 0

Question 6

What is global extinction?

Answer 6

extinction of a species

Question 7

What is local extinction?

Answer 7

extinction of a population

Question 8

When is the probability of extinction the highest?

Answer 8

When the population size is small and the rate of decline (birth-death) is high

Question 9

When does population size provide little protection from extinction?

Answer 9

when declines are due to external forcing is rapid or exponential

Question 10

What are the two types of extinction processes?

Answer 10

1. Stochastic process

2. Deterministic process

Question 11

What is stochastic process?

Answer 11

chance or random events; particularly problematic for geographically restricted species (species with small pop.)

Question 12

What is deterministic process?

Answer 12

traits related to extinction vulnerability

Question 13

Which traits are mentioned that are related to extinction vulnerability?

Answer 13

• geographic range
• dispersal ability
• trophic status
• specialization
• rarity
• population variability
• intrinsic rates of population

Question 14

What geographic range is less vulnerable to extinction?

Answer 14

large geographic range

Question 15

Which dispersal ability is less vulnerable to extinction?

Answer 15

higher dispersal ability

Question 16

Which trophic status is more vulnerable to extinction?

Answer 16

higher level tropic status

Question 17

Why is specialization more vulnerable to extinction than generalists?

Answer 17

because generalist can co-opt to different resources, but specialization is when a species is specialized on 1 particular resource and if that resource goes away they will not survive

Question 18

Why is rarity more vulnerable to extinction?

Answer 18

lower abundance

Question 19

Why type of population variability is more vulnerable to extinction?

Answer 19

higher variability

Question 20

What is the Kangaroo rat census at Portal AZ an example of?

Answer 20

An example to show how its population number is very variable

Question 21

What is intrinsic rate? What intrinsic rate is less vulnerable to extinction?

Answer 21

• The recovery rate after a catastrophe

- higher rates are less vulnerable

Question 22

What is the paleontological definition of mass extinction?

Answer 22

episodes of elevated extinction rates when more than 75% of species disappear within a geologically short time period, typically 2 million years or less

Question 23

What would cause mass extinction levels to be reached?

Answer 23

current extinction rates in some terrestrial vertebrate groups are high enough that mass extinction levels could be reached in the future IF all of the IUCN listed species go extinct

Question 24

Traits that affect extinction vulnerability tend to be what?

Answer 24

tend to be phylogenetically conserved- tend to run in families

Question 25

What is shown in the Huang and Roy phylogenetic distribution of reef corals? (2013)

Answer 25

- it plots different anthropogenic threats and different traits - ex: bleaching is affecting certain groups and not others. Traits/threats are not randomly distributed across the tree

Question 26

What occurs when non-random extinctions happens?

Answer 26

Loss of long branches which quickly erodes evolutionary history

Question 27

What is shown by the phylogenetic diversity and extinction threat in reef corals figure?

Answer 27

- Less projected excess Phylogenetic diversity (less evolutionary history) loss in higher species variability areas (such as the Coral Triangle). But higher phylogenetic species loss (short branches) in these areas - More projected excess phylogenetic diversity loss in less species variability areas, but less projected phylogenetic species variability loss in these areas

Question 28

Which type of extinction tend to preserve a lot of existing trait diversity?

Answer 28

Random extinction

Question 29

Which type of extinction erode a lot of the existing trait diversity?

Answer 29

Selective extinction

Question 30

What type of birds were more affected by extinction in the Gaston/Blackburn 1995 study?

Answer 30

Strong body size with large-bodied species were more threatened

Question 31

In which time period were larger vertebrates (>44 kg) selectively extinct in N.America?

Answer 31

Late Pleistocene Megafauna- about 11-12 thousand years ago

Question 32

When did large vertebrates begin to go extinct in Australia?

Answer 32

Pleistocene and Holocene

Question 33

What could have caused the Pleistocene Megafaunal extinctions?

Answer 33

- Timing of extinction are different on different continents but coincides with arrival of humans

Question 34

Why weren't there any major extinctions in Africa and Eurasia during the past 100,000 years?

Answer 34

Because it is where humans evolved and we coexited with animals

Question 35

What are examples of anthropogenic impacts and threats to species discussed in class?

Answer 35

- habitat destruction and loss - climate change - habitat loss and climate change - exploitations - invasive species - environmental degradation - interactions among different stressors

Question 36

What are examples of habitat destruction?

Answer 36

- clear cutting of forests - bottom trawling - urbanization

Question 37

What is the example of the passenger pigeon about?

Answer 37

- it was the most abundant bird in N. America (possibly in the world) - after european conquest of N.America-> heavily hunted as food and pets - By late 1890s the species was virtually extinct - Tried to protect it but making reserves-> Stochastic and Deterministic extinctions occurred - The last two individuals died in Cincinnati zoo (1910 and 1914)

Question 38

What caused the extinction of the Guam rail in the wild?

Answer 38

introduction of species

Question 39

What species was introduced?

Answer 39

brown tree snake