Today: Grizzly Bears
We are only
one of
millions
of
species
on
earth.
Ecological Interconnections
Grizzly Bears
Grizzly bears are
big.
How are bears related to each other?
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 28
12,000 years ago: the grizzly ancestor shortfaced bear
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 15
Short-faced vs grizzly bears
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 17 and 23
Grizzly bears live most of
their lives alone
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 78
Grizzly bears live most of
their lives alone.
What do they do?
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 78
… mostly eat
What do grizzly bears eat?
Ray deLucia and the Grizzly Bear Fight AMNH photo # 296899 Courtesy of the American Museum of Natural History Library Services
Different mouth
and teeth structures
can tell about an
animal’s diet
Fig 41.18
Grizzly bear
teeth
Different teeth and diets
grizzly
cat
dog
panda
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 54
Carnivores have a
short digestive system
Fig
41.19
Herbivores have a
long digestive system
Bears
Both humans
and grizzly
bears are
omnivores.
Our digestive
systems can
tell us about
our ancestors.
Fig 41.19
Humans
About 75% of their diet is plants
They also eat carrion.
Some grizzlies are excellent
predators, but most eat
carrion.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 85
Grizzlies constant
search for food can
lead to conflicts with
humans.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 186
Grizzlies constant search for food can lead to
conflicts with humans.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 215
There is not much to eat in winter...
Bears from
temperate
climates sleep
over the winter
in a den.
(not hibernation)
Grizzlies have an amazing ability to gain and
lose weight.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 62 and 63
Grizzly reproduction
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 59
Female Grizzly Bear reproductive cycle
juveniles
on own
den w/
mother
fall
summer
fertilization
winter
young
born
spring
Females are not fertile when caring for offspring
Grizzly Bear Reproduction
Spring
Summer
Fall
Winter
(in den)
Birth
year
copulation
delayed
gestation
implantation
birth
Juvenile
year 1
Offspring
with mom
(lactation)
Offspring
with mom
(lactation)
Offspring
with mom
(lactation)
Offspring den
with mom
(lactation)
Juvenile
Offspring
Offspring
Offspring
Offspring den
Grizzly cubs are born in the den and are very
small (~1 lb)
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 58
Female Grizzly Bear reproductive cycle
juveniles
on own
den w/
mother
fall
summer
fertilization
winter
young
born
spring
Females are not fertile when caring for offspring
Female bears are very protective of their young
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 76
Infanticide: males will try to kill young so
that mother will become fertile
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 77
Habitat
destruction
and hunting
have severely
decreased
grizzly
populations in
the U.S.
Current
Grizzly
Bear
range
Historical Grizzly
Bear range
Yellowstone NP
63 mi
54 mi
•466 mi of roads
•950 mi of backcountry trails
•97 trailheads
•287 backcountry campsites
Yellowstone Grizzly Bear population increases
Yellowstone NP
is not big enough
to support a
viable grizzly
bear population
Where do grizzly
bears fit?
Are they
important?
How much of our
resources should
we share with
grizzly bears?
Animal behavior is unpredictable and inexplicable
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 231
Experiment Written Report:
Title- Concisely describe your experiment.
Author
Abstract- Summarize your work. Do not exceed 250 words.
IntroductionResultsDiscussionMaterials and MethodsReferences- include: author name(s), article title, journal or
book title, volume and page number, and year of publication
Staple your approved proposal to the back of your written
report.
What is a reliable source?
xkcd.com
Building Blocks of Scientific Literature
What is peer
review?
peer review
In a peer reviewed journal each article is
looked at by an editor, and then it is then sent
to two anonymous reviewers.
These reviewers send comments back to the
editor.
After each article is sent to the editor, it is then
sent to two anonymous reviewers.
These reviewers send comments back to the
editor.
They give suggestions for improvement as
well as an opinion about whether it should be
published or not.
The editor then has three choices:
Accept paper as is. (rare)
Accept paper and ask for some changes.
Reject paper. (20-80% rejection rate in
physical sciences*)
*Scholarly Consensus and Journal Rejection Rates. Lowell L. Hargens (Feb., 1988) American Sociological Review
53: 139-151
and
Bang for Your Buck: Rejection Rates and Impact Factors in Ecological Journals. The Open Ecology Journal (2008)
L.W. Aarssen, T. Tregenza, A.E. Budden, C.J. Lortie, J. Koricheva and R. Leimu 1: 14-19
Who reviews papers?
Other researchers knowledgeable in the field.
What is a reliable source?
xkcd.com
What is a reliable source?
What is a reliable source?
Can be a great source of sources...
What is a reliable source?
Who was the author(s)?
Why was it written?
Where was it published?
Who checked/reviewed the article?
xkcd.com