Title: Parasite Box Model Example
1Parasite Box Model Example
- Brucellosis (undulant fever) is a bacterial
disease of ruminant mammals and sometimes of
humans. In ruminants, brucellosis causes a
decrease in milk production, and can cause cows
to abort their calves. It has been in the news
because of concern that brucellosis infected
bison in Yellowstone National Park may be able to
spread the disease to cattle. Construct a box
model and then write equations that show how
brucellosis affects a population of bison. Once
an animal is infected with brucellosis, it will
carry the disease for the rest of its life.
There is vertical transmission of the disease
from mothers to offspring. In your box models
and equations you should account for x - the
of uninfected susceptible bison, y - the of
infected bison, a - per capita host birth rate
for uninfected offspring, b - natural,
non-disease mortality rate, alpha a - disease
induced mortality rate, beta ß - transmission
coefficient, and zeta ? - birth rate of infected
young.
2Symbioses - Mutualism
3Endosymbiotic Origin of Eukaryotes
Lynn Margulis
4Endosymbiotic Origin of Eukaryotes
5Endosymbiotic Origin of Eukaryotes
- The earliest eukaryotes acquired mitochondria by
engulfing alpha proteobacteria. - The early origin of mitochondria is supported by
the fact that all eukaryotes studied so far
either have mitochondria or had them in the past.
Mitochondria have their own DNA and replicate
themselves during cell division. - Later in eukaryotic history, some lineages of
heterotrophic eukaryotes acquired an additional
endosymbionta photosynthetic cyanobacteriumthat
evolved into plastids. - This hypothesis is supported by the observation
that the DNA of plastids in red and green algae
closely resembles the DNA of cyanobacteria. - Plastids in these algae are surrounded by two
membranes, presumably derived from the cell
membranes of host and endosymbiont.
6Stromatolites on coast of Western Australia
7The Nature of Communities and Ecosystems
8Sourdough bread ingredients and final product
9Redwood Forest
10Scale of Ecosystem Lake Superior
11Scale of Ecosystem Isle Royale
12Scale of Ecosystem Isle Royale Forest and
Pond
13Scale of Ecosystem Isle Royale Wetland
14Scale of Ecosystem Isle Royale Pitcher Plants
15Ecotone region where two communities/ecosystems
grade into each other
Forest-Marsh Ecotone
16Stability
- A stable community or ecosystem is one that has
the ability to replace itself exist in place
for more than one generation
17Douglas-Fir
18Pea Aphids
19Life cycle of the Pea Aphid
20Components of Stability
- 2 major components
- 1) resistance - the ability of a community or
ecosystem to avoid disturbance - how most people
think of stability - 2) resilience - the speed with which a community
or ecosystem returns to its former state
following a disturbance that has displaced it
from its initial condition
21Ecosystems and Stability
Grassland South Africa Rainforest Puerto Rico
22Additional Components of Stability
- Local stability describes the tendency of a
community to return to its original state
following a small disturbance - Global stability describes the tendency of a
community to return to its original state
following a large disturbance
23Adaptive Capacity of an Ecosystem
24Adaptive Capacity of an Ecosystem
25Adaptive Capacity of an Ecosystem- Chesapeake Bay
26Adaptive Capacity in 3D
27Current Adaptive Capacity
28From Local vs. Global Stability
- dynamically fragile - a community which is stable
only within a narrow range of environmental
conditions - dynamically robust - a community which is stable
within a wide range of environmental conditions
29Complexity and Stability
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32Current understanding - no clear relation between
complexity and stability
- 1) complex, fragile communities of relatively
constant environments (the tropical rainforests)
are more susceptible to outside, unnatural
disturbances than are simpler, more robust
communities which experience regular climatic
fluctuations (most temperate communities) - 2) In stable environments you would expect to
find K selected species (high competitive
ability, high survivorship, low reproductive
output) and such species will resist disturbance - 3) In unstable environments you would expect to
find r selected species (low competitive ability,
low survivorship, but high reproductive output)
that have little resistance but high resilience
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34Aerial view Of 1989 Yellowstone Fire
35Why is the World Green?
Boreal Forest Outlined in Green
36Spiny Water Flea
37Spiny Water Flea Invasion
38Mary Power
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40Eel River with steelhead Eel River without
steelhead