Transcript 4/21 - Utexas

Succession:
How does
biodiversity
occur?
Exam #4 W 4/23 in class
(bring cheat sheet)
Review T 4/22 at 5pm in
WEL 1.316
CB 55.2
Genetic Diversity
Biodiversity- number of
species within an area
Ecosystem Diversity
Ecosystems on Earth
CB
50.19
Primary Succession- the first organisms to
colonize bare rock
Secondary Succession- recovery from a
disturbance
Primary Succession- from non-living to living
Primary
succession as
this glacier
retreats
CB 53.23
Primary
Succession
after glacier
retreat,
150-300 years
Primary Succession: each
stage helps enable the next
CB 53.24
Primary succession after a volcanic eruption
1
2
3
4
5
CB 53.2
Competition limits where species can live
niche- the specific environment where
a species lives
CB 53.2
Tree species existing in different niches
CB 53.3
CB 53.22
Secondary Succession: after a fire
CB 53.21
Grassland biodiversity and biomass are
increased by regular burns
Secondary Succession of a
field
(20 yrs)
CB 55.21
Human vs Natural Disturbances
Chernobyl fire
April 26, 1986
The Chernobyl accident was by far the largest
unintentional release of radioactive material
into the environment and caused widespread
contamination in Europe.
After the accident on April 26, 1986, ~116,000
people were evacuated, most from a zone of
30-km radius. That included about 45,000
people from the town of Pripyat.
The most heavily exposed emergency workers
received doses that were sufficiently high to
kill them in the weeks and months after the
accident.
Chernobyl April 26, 1986
Cancer consequences of the
Chernobyl accident: 20 years
on J. Radiological Protection
26 (2006) 127–140
Elisabeth Cardis et al.
Mitosis
Cancer: Cell Division Gone Wrong
The rapidity of increased childhood thyroid
cancer in the heavily contaminated areas of
Belarus, Ukraine and Russia was surprising.
4 years
The issue of the effects on health of the Chernobyl
accident has become part of the political debate over
the future role of nuclear energy, which has inevitably
led to dispute over the level of effects either observed
or anticipated.
After the accident on April 26, 1986, ~116,000
people were evacuated, most from a zone of
30-km radius. That included about 45,000
people from the town of Pripyat.
For more pictures: http://www.nikongear.com/Chernobyl/Chernobyl_1.htm
What about non-human inhabitants?
turtle in exclusion zone
The 30-km radius exclusion zone
Initially many animals died from the huge
doses of radiation they received.
The red color of withered pine needles earned
one large area near the reactor the name Red
Forest.
"Now it is not the Red Forest but a real green
forest, due to [growing] birch trees," said
Sergey Gaschak from the International
Radioecology Laboratory in Kiev, Ukraine.
Many human tragedies have been a boon for
native animal species:
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=15362
Science v. 269 pg. 304 7/21/1995
Korean DMZ: Among the species making their
homes in the DMZ are endangered Asian cranes,
black-faced spoonbills, angora goats, Amur leopards,
and even bears.
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=15362
Savanah River nuclear site in Georgia:
forest remnant
A herd of Przewalski's horses roams Ukraine's
Chernobyl exclusion zone.
http://news.nationalgeographic.com/news/2006/04/0426_060426_chernobyl.html
And in the towns where humans have moved
out, plants and animals have moved in.
Background radiation levels near the
Chernobyl reactor are 3000 times higher than
near the Savannah River nuclear reactor
Science v. 269 pg. 304 7/21/1995
Late last year Moller and Mousseau published
a paper in the Journal of Animal Ecology
showing that reproductive rates and annual
survival rates are much lower in the
Chernobyl birds than in control populations.
"In Italy around 40
percent of the barn
swallows return
each year, whereas
the annual survival
rate is 15 percent or
less for Chernobyl.
Mutation isn't the only adverse effect of the
radiation. Working in the Red Forest area,
James Morris, a USC biologist, has observed
some trees with very strange twisted shapes.
The radiation, he says, is confusing the
hormone signal that the trees use to determine
which direction to grow.
"These trees are having a terrible time
knowing which way is up," Morris said.
Unusual growth in
“Red Forest” pine
trees
The most recent count by the authorities showed that
the zone (including a larger contaminated area in
neighbouring Belarus) is home to 66 different species
of mammals, including 7,000 wild boar, 600 wolves,
3,000 deer, 1,500 beavers, 1,200 foxes, 15 lynx and
several thousand elk.
The area is also estimated to be home to 280 species of
birds, many of them rare and endangered. Breeding
birds include the rare green crane, black stork, whitetailed sea eagle and fish hawk.
But Mousseau is less optimistic. "One of the
great ironies of this particular tragedy is that
many animals are doing considerably better
than when the humans were there," he said.
"But it would be a mistake to conclude they
are doing better than in a control area. We just
don't know what is normal [for Chernobyl].
There just haven't been enough scientific
studies done."
Exam #4 W 4/23 in class (bring cheat sheet)
Review T 4/22 at 5pm in WEL 1.316