Extinction

Question 1

Average lifespan of a species

Answer 1

1-3 m years

Question 2

Causes of extinction

Answer 2

Climate change, natural disasters, other

• as some species originate, they inevitably drive other species extinct
• extinctions in turn pave the way for speciation e

Question 3

Background

Mass

Answer 3

Background: low but steady rate of extinction of species

Mass: rare (but periodic) pulse of intense extinction of large proportion of species

Question 4

Background extinction

Answer 4

Org. Have a background extinction rate because of normal ecological or evolutionary processes (and as they disappear other species take their place)

Question 5

5 mass extinction

Answer 5

Ordovician Silurian: 440 mya trilobites

Late Devonian: 365 mya Taxa lost after life amphibians

Late Permian: 250 mya most life lost

Terminal Triassic: 200 mya 20% all marine lost

Terminal Cretaceous: 65 mya dinosaurs lost

Question 6

Sixth mass extinction

Answer 6

Holocene: started 50,000 yrs ago to present day. Loss of 50% of vertebrate and unknown number of invertebrates

Question 7

Periodic mass extinction

Answer 7

26 mil yr of periodicity

1. Asteroid impact (impact craters)
2. Some deep-earth dynamics? Outbreaks of massive volcanic activity

Question 8

Humans role in extinction; large mammals vanished from N America (big game hunters arrival)

Answer 8

How could they had simple hunting?

• climate change(last ice age glaciers retreating, earth warming)
• bolide impact (large crater-forming projectile)
• hyper-disease
• combo of all

Question 9

Role of disaster taxa

Answer 9

• some sp formerly uncommon now have greatly enlarged ranges and much higher numbers
• typical of mass, a small number of disaster taxa proliferate and fill ecological voids left in wake of ask many vanished species

Question 10

Major source of anthropogenic extinction (HIPPO)

Answer 10

Habitat destruction
Invasive species
(Human) population 
Pollution
Overexploitation

Question 11

After mass extinction or ecological void adaptive radiation (wave of speciation) occurs because of

Ecological opportunity

Morphological innovation

Answer 11

Ecological opp:

• when a linage is free from usual constraints of interspecific competiton, exploit underutilized or completely novel ecological niches.
• new opportunity to exploit resources in wake of another lineage

Morphological:
-a new habitat is colonized by a lineage in response to evolutionary novelty that allows it to live in a diff way