Transcript Document 7168417

Figure 26.15 Whittaker’s five-kingdom system
Periodic
extinctions
have occurred
naturally –
There have
been five.
The asteroid impact hypothesis (Luis and
Walter Alvarez)-Asteroids collided with the earth
-Force of collision spewed large amounts of debris
into the atmosphere
-The skies got dark for several years
-No sun – no photosynthesis - no plants/less plants
-No food – starvation of herbivores and subsequently
of carnivores
Life in the Cenozoic Era
• Present era
• Geological shift
• Shifts in climate
• Adaptive radiation of
mammals
– Tropical forests
– Woodlands
– Grasslands
• Species diversity
The archaic mammals of the Paleocene
Epoch included such animals as
Causes of Extinction
Quaternary Extinction
Newly introduced species brought about extinction
through increased competition. Widespread glaciation
caused a decline in sea levels. Which resulted in the
emergence of land bridges, including those across
Panama, the Bering Strait, etc.
Many species were introduced from one land mass to
another. Newly introduced species competed with other
species already present and established new predator –
prey interaction. Many could not adjust to the new
conditions and became extinct as a result
Causes of Extinction
The Human Role In Extinction
The activities of humans, including both hunting
and alteration of habitat, played a large role in
the extinctions of the past 50,000 years
Australia - 20 species of kangaroo, marsupial lion, a
marsupial wolf
Hawaiian Islands – flightless birds
New Zealand – the giant moa (an ostrich-like flightless
bird)
Madagascar – flightless bird (elephant bird)
The extinction of many
large mammals and
flightless birds followed
soon after human
arrival in many parts of
the world
In Africa, however,
extinction took place
more gradually because
humans had been
present for a much
longer time
Extinction the
cost of not being
sustainable
But some species have
survived these major
extinctions such as the
alligators and
crocodiles.
The birth of
civilization has seen
the unprecedented
destruction of
wildlife
However, the
advent of man
has increased the
rate of
extinctions e.g.
the mammoth
the dodo is yet
another extinction
caused by man
As Man
changes his
environment it
changes so
that other
species will
also not coexist with him.
Niger Rock engraving
Location of Giraffe Rock engraving
The birth of
civilization has seen
the unprecedented
destruction of
wildlife
Emperor Caligula had
400 bears and 400
other wild animals
slaughtered in a single
sitting!
Pharaoh Ramses hunted
and “killed 102 wild-eyed
lions” in a single hunt!
Emperor Trajan to
celebrate a victory
organized a circus
which saw 11 000
animals butchered!
Even today the killing
continues in the name
of sport hunting or
medical science.
Civil disputes also
threaten some
species with
extinction
The Cape Flats is
witnessing the
highest plant
extinction rates any
where in the world!
“In just a few Centuries, the people of Easter
Island wiped out their forests, drove their
plants and animals to extinction, and saw
their complex society spiral into chaos and
cannibalism.
Are we about
to follow their
lead?”
(Diamond 1995).
“...what is perhaps most intriguing in the
evolution of human societies is the
regularity with which the pattern of
increasing complexity is interrupted by
collapse…”
(Joseph Tainter 1995, The Collapse of Complex Societies)
Extinction is for
Keeps
Issues Facing
the World
Facing the 6th
Extinction
Becoming drier?
Becoming wetter?
Increased sea levels?
More deserts?
Leaching & Erosion
Energy use & Mechanisation
How will changes impact on our lives?
Soil damage
Natural habitat & Disturbances
Global deforestation
e.g. Exmoore used to be
forested but they were cut
down to build warboats
Changes to global
weather patterns
e.g. 2001 floods of
Mozambique
Air Pollution
CFCs have been linked to
the destruction of the
Ozone layer above
Antarctica.
Desertification – through
unsustainable grazing
e.g. Sahel
Loss of soil causes these
sediments to smother
coral reefs
e.g. Madagascar – the
bleeding island!
Invasions of introduced
species
e.g. Pampas Grass along
the Californian coast
Sealand Express
Water Pollution
Exxon Valdez - largest
marine pollution event
The Treasure – largest
evacuation of marine birds
Overpopulation
The human population
has doubled in the last
40 years.
Rapid Urbanization
Cape Town is predicted
to have a population of
5.8 million by 2010!
Nuclear War
Both developed and
developing countries
have the potential to
unleash a nuclear winter
for the entire earth!
Here are some
facts…
Almost 25 Million
people die each
year due to a lack
of clean water
and adequate
sanitation
One-third of the world’s
population have no
access to commercial
energy
In Africa, 340 million
people or half of the
population, live on
less than US$1 a day
The richest 1% of
the world’s people
receive as much
income as the
poorest 57% in
1993
The world has 600
million sheep and
goats, 360 million
cattle and 6.1
billion people!
The Earth’s
temperature could
increase by 6 degrees
Celsius by 2100!
The Northern
Hemisphere’s summer
this year was the
hottest on record.
37% of the world’s
population are
vulnerable to the
effects of rising
sea levels
One-third of global
biodiversity is
concentrated into
1% of the Earth’s
surface.
A quarter of the
planet’s mammal
species are now at
risk of extinction.
A quarter of all
plant species in
the world could be
extinct by 2025!
Half of the world’s
coral reefs are
now at risk of
extinction.
70% of fisheries
are depleted or
fully exploited.
UK customs
confiscated some
1600 live animals
and 1800 plants
that are on the
endangered
species list!
So what does the
future hold for the
earth’s species
including ourselves?
Defining
Sustainability
Meaning of sustainability
Latin root word is sustinere, where the
“sus” part means up, and the “tinere” is
like tenure, meaning to hold.
Thus to sustain something is to hold it
up, to support it, to keep it up or prolong
it, or to support it as true, legal, or just.
1. Different ways of interpreting the
meaning of sustainability
2. Some key international milestones in
sustainable development e.g. World
Summit on Sustainable Development
3. Expanding the traditional economic
notion of capital
4. Changes the way we undertake
Conservation and Manage Ecosystems
Elements of Sustainability
… maintenance of biological diversity and the integrity of ecological processes and systems.
Ecological Sustainability
Global Sustainablity
Social Sustainability
… maintenance of the human community that
depends upon the forest.
Economic Sustainability
… maintenance of companies, communities,
and families that are economically dependent
on forests.
Adapted from Floyd, 2002
Ecological
footprints
“…the science of economics has fashionable models of
both national and global economies which generate
policies that have something particularly interesting in
common. It is that they do not work.”
(Stafford Beer 1981
These stones recently found in the Blombos Cave, South Africa, have been
dated at 77,000 years old, making them the oldest form of recorded counting
The ‘ecological footprint’
is the area of land and water
ecosystems required to produce
the resources that the population
consumes, and to assimilate the
wastes that the population
produces,wherever on Earth the
relevant land/water may be
located
Humans display a
uniquely broad and
ever-widening food
niche which
extends from nearly
pure carnivory to
obligate herbivory.
Humans are uniquely adaptive which enables them to
exploit virtually all the ecosystems and ‘environments’ on
Earth.
Consequently humans are the dominant consumer
organism in all ecosystems types on Earth.
Systems that prevail
(i.e., successful
systems) are systems
that evolve to maximize
their use of the energy
[and material]”
(Lotka 1922)
This leads to the concept of
competitive exclusion
Competitive exclusion: The expansion
of the human activities
Loss of natural resources
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Eco-Footprint (hectares)
Per Capita Ecological Footprints of Selected Countries
14
12
10
8
6
4
2
0
Over-Shooting Carrying Capacity
18
Billions of Hectares
16
14
12
10
8
6
4
2
0
Area of Productive
Ecosystems on Earth
Estimated Global Ecological
Footprint
Available and Appropriated Carrying Capacity
At the limits of
biophysical carrying
capacity, routine but
non-essential
consumption by the
rich can result in
violent harm to the
poor and racial
minorities
In 1998, a record number of natural disasters drove 25
million “environmental refugees” from the land and their
homes into shanty towns throughout the developing world.
Red Cross, 1999 World Disasters Report
Human populations are characterized by depleting both
self-producing and non-renewable ‘natural capital’ stocks
(other species populations; forests; ground water).
For sustainability, global society
must create a new cultural myth
The underpinning values of society must
shift from a focus on individualism,
narrow self-interest, and an emphasis on
competitive relationships toward greater
emphasis on community and societal
values, cooperative institutions, and
participatory consciousness with nature.
“It has often been said that, if the human species
fails to make a go of it here on Earth, some other
species will take over the running. …this is not correct.
We have, or soon will have, exhausted the necessary
physical prerequisites so far as this planet is concerned.
With coal gone, oil gone, high-grade metallic ores gone,
no species however competent can make the long climb
from primitive conditions to high-level technology. This
is a one-shot affair. If we fail, this planetary system fails
so far as intelligence is concerned.”
Sir Fred Hoyle 1964, Of Men and Galaxies
The time has come
to develop
sustainable
planning to
conserve our
plants resources
Otherwise we will
have no heritage or
future for our
children and their
children.
This is why the
Botany and Zoology
departments at
UWC merged and
introduced the
Biodiversity and
Conservation
Biology programme
Are you ready
to face these
challenges?
European Rock Paintings
Bolivian Rock Paintings
`
Aboriginal Rock Paintings
THE ETHIC OF SUSTAINABILITY
• As a central value and guideline for action in
both public and private spheres,
sustainability’s implications and requirements
include:
• Concern for Future Generations
• Respect for Ecological Integrity
• Responsible Earth-Keeping
• Rededication to Justice
• Respect for Community
• Rededication to Civic Democracy and Civic
Dialogue
Present status of
the world… or why
it is currently not
sustainable