5. FOUR WAYS TO SURVIVE
MASS EXTINCTIONS
1! Have a wide geographic range"
Marine
bivalves
that
had
large
ranges
were
more
likely
to
survive
the
cretaceous
ex+nc+on
6. FOUR WAYS TO SURVIVE
MASS EXTINCTIONS
2! Be lucky"
7. FOUR WAYS TO SURVIVE
MASS EXTINCTIONS
3! Be an omnivore or scavenger/
Don’t rely on plants "
8. FOUR WAYS TO SURVIVE
MASS EXTINCTIONS
4! Hibernate or diapause "
12. EXTINCTIONS IN MAMMALS
Ex+nc+on
rates
if
we
lost
Vulnerable
(VU)
Ex#nc#ons
per
Million
Species
Endangered
(EN)
and
Cri+cally
Endangered
(CR)
species
Years
Barnosky
et.al.
2011
13. THE 6th MASS EXTINCTION?
75%
Barnosky
et.al.
2011
14. THE 6th MASS EXTINCTION?
Ex#nc#ons
per
Million
Species
Rate
of
ex+nc+on
if
historical
ex+nc+ons
were
compressed
Years
into
500
years
Actual
rate
of
ex+nc+on
(occurred
over
1000s
of
years)
Barnosky
et.al.
2011
27. WAS IT OVERKILL?
Evidence
For
Human
Overkill:
• Ex+nc+ons
coincide
with
first
confirmed
human
seZlements
• Most
ex+nct
species
evolved
from
American
ancestors
(no
prior
contact
with
humans)
Evidence
Against
Human
Overkill:
• Small
human
popula+on
size
at
the
+me
• Few
human
archaeological
sites
with
ex+nct
mammal
remains
29. AUSTRALIAN WILD LIFE
100,000 YEARS AGO
Diversity
of
large
terrestrial
vertebrates
in
mid-‐
Pleistocene
(<100,000ya)
• 57
marsupials
>10kg
• Varanid
lizards
(e.g.
komodo
dragons)
• Large
flightless
birds
45. FISHING IN LAKE WINDEMERE
1963
:
Peak
of
Gill
net
fisheries
Net
Fisheries
No
Fishing
Gill
Nets
(12th
Century
–
1921)
1921-‐1944
1944-‐1980
46. GROWTH RATE AND FISHING
SELECTIVE PRESSURE
Gill
nets
have
holes
of
a
standard
size
SMALL"
Fish
survive
this
ar+ficial
selec+on
47. GROWTH RATE AND FISHING
SELECTIVE PRESSURE
Predators
and
cannibals
are
important
sources
of
mortality
for
pike
LARGE"
Fish
survive
this
natural
selec+on
48. GROWTH RATE AND FISHING
SELECTIVE PRESSURE
(Edelene
et.al.
2007)
49. KEY POINTS
We aren’t quite to the 6th Mass Extinction"
But…
Losing
threatened
species
will
bring
us
close
to
mass
ex+nc+on
levels