Transcript GC1 roadmap_2005_All..

Evolution and Ecology Roadmap
We wish to know:
• Where we are going
• Why we should care
• How the pieces fit
together
• And, maybe… Who is
this guy?
http://tolweb.org/tree/
phylogeny.html
My themes
• Human-induced changes to the planet need
to be understood within the context of
natural processes and evolutionary change
• Not just climate change: global
deforestation and desertification, overharvested resources, global homogenization
of species, altered mineral cycles
• Life diversity and life processes are at risk
The approximate number of pirates vs the average global
temperature for the past 200 years. A statistically
significant decline in number of pirates with rising global
temperature is clearly evident.
We need to be educated consumers of information!
Evolution and Ecology Roadmap
• Where we are going….
– The study of origins, the generation of life diversity, ‘the
ecological theatre and the evolutionary play’
• Why we should care
– Environmental change impacts our lives
– Many important issues have a substantial scientific
component: teaching of intelligent design, legalization of
stem cell research, cloning, preservation of nature
– Importantly, these issues also have significant moral and
ethical implications
• How the pieces fit together
– Time and earth history; climate; biodiversity and
ecosystem function
Efforts to Reconcile God and Nature
Charles Darwin
1809 - 1882
In order to pass the B.A. examination, it was, also, necessary
to get up Paley's Evidences of Christianity, and his Moral
Philosophy. . . The logic of this book and as I may add of his
Natural Theology gave me as much delight as did Euclid. The
careful study of these works, without attempting to learn any
part by rote, was the only part of the Academical Course
which, as I then felt and as I still believe, was of the least use
to me in the education of my mind. I did not at that time
trouble myself about Paley's premises; and taking these on
trust I was charmed and convinced of the long line of
argumentation.
Charles Darwin. Autobiography
Natural Theology: or, Evidences of the Existence
and Attributes of the Deity, Collected from the
Appearances of Nature. Published 1802
William Paley
(1743 – 1805)
“. . . when we come to inspect the watch, we perceive. . . that its
several parts are framed and put together for a purpose, e.g. that
they are so formed and adjusted as to produce motion, and that
motion so regulated as to point out the hour of the day; that if
the different parts had been differently shaped from what they
are, or placed after any other manner or in any other order than
that in which they are placed, either no motion at all would have
been carried on in the machine, or none which would have
answered the use that is now served by it. . . . the inference we
think is inevitable, that the watch must have had a maker..”
To account for the often amazing adaptations
of animals and plants, Paley argued that only
an intelligent Designer could have created
them, just as only an intelligent watchmaker
can make a watch
In its preface, Dawkins states that he
wrote the book "to persuade the reader,
not just that the Darwinian world-view
happens to be true, but that it is the only
known theory that could, in principle,
solve the mystery of our existence." The
book is widely regarded as clearly-stated
and forceful. However, …. it has been
noted that he makes no attempt to
explain the origin of matter and energy,
space, and time—the material and
framework of evolution—nor the origin
of physical law—the underlying rules
for evolution.
Wikipedia – the free Encyclopedia
On The Origin of Species by Means of Natural Selection,
or
The Preservation of Favoured Races in the Struggle for Life
by Charles Darwin
First Edition, 1858
Darwin’s Theory of Evolution
• Organisms have changed over
time; those living today are
different than they were in the past
• All organisms are derived from
common ancestors by a process of
splitting, or speciation, that gave
rise to the entire tree of life
• Change is gradual and slow, taking
place over a long time
• The mechanism of evolutionary
change is natural selection
The Aftermath
“was it through his grandfather or his
grandmother that he claimed his descent
from a monkey? “
Oxford, June 30, 1860: Bishop Wilberforce
question to evolutionist Thomas Huxley,
known as “Darwin’s bulldog” for his
vigorous defense of Darwin’s theories.
The Steady March of New
Evidence
• Scientists in Spain discovered fossils of
ape species from about 13 million years
ago. This may have been last common
ancestor of all living great apes, including
humans. (NY Times Nov 2004)
• A consortium of scientists recently
completed a first sequence of chimp
DNA. Comparison of similarities and
differences help us explore recent human
evolution and understand the genetic basis
of uniquely human traits.
(Nature 1 Sept 2005)
Pierolapithecus
catalaunicus
Why study chimpanzees?
• To better understand chimp and human evolution
• To ensure their survival
• A model species for the study of diseases (hmm…)
• Study of origins
Threats to the
Great Apes
Audubon.org
• Bushmeat trade
• Habitat loss
• Illegal capture for zoos and
experimentation
• Diseases (ebola), and from
humans (polio)
Today Gombe, only eight miles long
and one to two miles wide, is
surrounded by farms and people,
including thousands of refugees fleeing
violence in nearby countries.
Threats to Biodiversity
Human actions now threaten species and ecosystems to
an extent rarely seen in earth history.
Habitat
destruction
Over-harvest
Climate
change
Exotic species
Why should we care about
biodiversity?
• The wonder of nature
• Ecosystem goods and services
– Clean water, productive soils, the
recycling of nutrients, food and fiber,
recreation, spiritual renewal
• The accelerating rate of species
loss
• Emerging diseases
http://www.divegallery.
com/Leafy_Sea_Drago
n.htm
Why should we care about
biodiversity?
• The wonder of nature
• Ecosystem goods and services
– Clean water, productive soils, the
recycling of nutrients, food and fiber,
recreation, spiritual renewal
• The accelerating rate of
species loss
• Emerging diseases
The March of the
Penguins,
narrated by
Morgan Freeman
http://www.divegallery.
com/Leafy_Sea_Drago
n.htm
Species-Area
Relationships
z = slope
Studies of plant and animal
biogeography have
established a log-linear
relationship between number
of species in an area, and
areal extent. An example for
the reptiles and amphibians
for the Caribbean is shown
with the area axis reversed,
to illustrate that reduction in
area leads to a reduction in
species.
Estimating Rates of Species Loss
• The relationship between number of species and
area of habitat is S = c A z
• the rate of loss of tropical forest from satellite
imagery is 1-2% annually
• the resulting loss rate of species results in an
overall loss of 25 - 50% of the world’s species by
2100
• Assuming tropical forests harbor 10 million
species, this loss is 27,000/yr (and 3/hr)
The Ecology of Infectious Diseases
Albrecht Durer's The Four Horsemen
of the Apocalypse
I looked, and there before me
was a pale horse! Its rider was
named Death, and Hades was
following close behind him.
They were given power over a
fourth of the earth to kill by
sword, famine and plague, and
by the wild beasts of the earth.
Revelations 6:7
The threat of infectious diseases
is increasing
• Human activities continue to cause environmental
disruptions that can potentially favor new disease
emergence
• Most pathogens evolve rapidly
• Global travel facilitates rapid spread
The 1918 influenza affected 20-40
million people, and had a 5%
mortality rate. Ebola has an 80%
mortality rate. Current concern for
bird flu is justified.
Emerging Infectious Diseases
• EIDs: diseases that are, or have recently, increased in
incidence, impact, pathogenicity, geographical or host
range
• Causative agents of infectious diseases are among the
most ubiquitous organisms on the planet
• Typically capable of high rates of evolutionary
change, allowing them to adapt readily to new hosts
and habitats
• Examples include:
– Malaria, Lyme, WNV, Dengue, Schistosomiasis
– SARS, HIV, Ebola, Bird flu
Bushmeat Trade
• For the tropical forests of central and west Africa
(the Congo Basin rainforests), greatest threat to
vertebrate species is over-hunting for subsistence
and commerce
• For people living in these areas, up to 90% of total
animal protein may be derived from wild animals
Human Immunodeficiency Virus
• Genetic analyses indicate Human
Immunodeficiency Virus Type 1 (HIV-1)
originated in at least three zoonotic transmissions
of SIVcpz from chimpanzees (Pan troglodytes
troglodytes) to humans
• HIV-1 first identified from blood samples
collected in Kinshasa, Congo, in 1959
• Actual origin probably much earlier, possibly
during the period of French colonial
administration of French Equatorial Africa
Bushmeat Origin of HIV-1?
• This most probably occurred in the course of
hunting and butchering apes for food
• Considering that the consumption of apes is not a
new practice, transmission of SIVcpz to humans
has probably taken place regularly at some low
frequency for thousands of years
• What has caused recent
emergence of HIV?
Increased Exposure Risk
• Colonial authorities conscripted local
people for work as porters and forced labor
• People fled villages to live in the forests
• Those conscripted were poorly fed and were
no longer able to produce food through
agriculture
• Both would have increased reliance on
bushmeat for sustenance
Increased Viral Transmission
• During this period there was a massive
influx of rural peoples into major cities
• This increased urbanization would have
created conditions favorable to the initial
establishment of the disease
• Likely disrupted traditional social practices
and networks that governed sexual behavior
Viral Adaptation
• Large-scale attempts to control infectious diseases
relied upon massive, poorly-funded inoculation
campaigns
• Example: Six syringes used to screen and treat
nearly 90,000 people for sleeping sickness in
1917-1919
• Rapid passage of a virus through a series of hosts
over a relatively short period of time can select for
more virulent pathogen strains
Biodiversity and Disease Dynamics
• The presence of a diverse assemblage of
vertebrates can dilute disease incidence
• Occurs when reservoir competence varies among
host species and the most competent reservoir host
tends to be a community dominant.
• Vertebrate communities with high species
diversity will contain a greater proportion of
incompetent reservoir hosts that deflect blood
meals away from the most competent reservoirs
Lyme Disease
• An example of the dilution effect occurs in the
ecology of Lyme disease, a tick-borne bacterial
disease prevalent in North America
• The principle reservoir, the white-footed mouse,
increases dramatically in abundance in fragmented
habitats that contain low vertebrate diversity (due
to loss of predators and competitors)
• More intact community assemblages effect a
decrease in mouse abundance, resulting in less
infected ticks and less disease risk to humans
Forest Fragmentation and Lyme
Disease Risk
My themes
• Human-induced changes to the planet need
to be understood within the context of
natural processes and evolutionary change
• Not just climate change: global
deforestation and desertification, overharvested resources, global homogenization
of species, altered mineral cycles
• Life diversity and life processes are at risk
Possible Projects
• The influence of global
warming on coral reefs
• The bird flu pandemic of
2006
• Is Nemo a mutualist or a
commensalist?
• Rapid evolution in
Darwin’s finches
• Can reforestation
significantly slow global
warming?
• Loss of rainforests
threatens biodiversity
• How many kingdoms of
life are there?
• How much biodiversity is
needed to protect
ecosystem function?
• The effects of climate
change on nature reserves