ecological extinction
TRANSCRIPT
What is Extinction?
Extinction occurs when the last existing member of a given species dies
In other words…there aren’t any more left!
It is a scientific certainty when there are not any surviving individuals left to reproduce
Functional Extinction
Only a handful of individuals are left
Odds of reproduction are slim
Causes of Extinction
Genetics and Demographics
Small populations = increased risk
Mutations
• Causes a flux in natural selection
• Beneficial genetic traits are overruled
Loss of Genetic Diversity
• Shallow gene pools promote massive inbreeding
Causes Con’t.
Habitat Degradation
One of the most influential
Has many causes
Some due to humans
Some due to other factors
Habitat Degradation
Toxicity
Kills off species directly through food/water
Indirectly via sterilization
Can occur in short spans (a single generation)
Can occur over several generations
• Increasing toxicity
• Increasing competition for habitat resources
Habitat Degradation
Destruction of Habitat
“Save the Rainforests!”
Elimination of living space
Change in habitat
• Rainforest to pasture lands
Leads to diminishing resources
• Increases competition
Can be caused by natural processes
• Volcanoes, floods, drought, etc…
Predation
Introduction of predators
Invasive alien species
Transported by humans
• Cattle, rats, zebra muscles, etc…
• Sometimes on purpose, sometimes not
Can eat other species
Eat food sources
Introduce diseases
Coextinction
The loss of one species leads to the loss
of another
Chain of extinction
Can be caused by small impacts in the
beginning
A predator looses its food source
Affected by interconnectedness in nature
Mass Extinction
Aka: an extinction event
A sharp decrease in the number of
species on Earth in a short period of time
Coincides with a sharp drop in speciation
The process by which new biological species
arise
There have been at least 5
Last one was 65M years ago
Mass Extinction
Nearly 2/3rds (or more) of all animal
species that ever existed on the planet are
now gone. • With contemporary extinction being attributed to
HUMAN activity.
Numerous factors go into the extinction of
a specific species.• Though all point the finger to climate change.
Mass Extinction
Began about three-million years ago (Continental Glaciations).
Hypotheses for initial extinction:• Sea level depletion vs. Temperature decrease
Though these hypotheses aren’t mutually exclusive, they may have conspired together.
Mass Extinctions
1. Cretaceous-Tertiary Extinction (65).
2. End Triassic Extinction (200).
3. Permian Triassic Extinction (250).
4. Late Devonian Extinction (364).
5. Ordovician-Silurian Extinction (440).
(#= millions of years ago)
Planned Extinction
Human controlled
Thought of to help humans
Deadly viruses
Smallpox
• Extinct in the wild
Polio
• Near extinct (only in small parts of the world)
Asteroids
Causes complete
devastation
Flattening and crater at
or around impact site-
hundreds of miles wide
Reverberations felt around
the world
Disease/Epidemics
Can wipe out entire
species
Frog with fungus
disease
Killing frogs and other
amphibians
Natural factors usually occur at a slower
rate and therefore cause a low extinction
rate. Human activities occur at a faster
rate and cause higher extinction rates.
Human activities are mostly responsible
for the present extinction rates.
http://www.gov.mb.ca/conservation/sustain/extinct.pdf
Top Human Causes of
Extinction:
Increased human population
Destruction/Fragmentation of
habitat
Pollution
Climate change/Global warming
Extinctions caused by humans are generally
considered to be a recent phenomena. HOWEVER:
•In Australia—earliest humans: 64,000 years ago
extinction—30,000-60,000 years
ago
•In the Americas—80% of large animals became
extinct around the same time as first human presence
there
Based on these, and other
studies done by The
international Union for
Conservation of Nature
and Natural Resources
(IUCN), human induced
extinctions are not
necessarily a new
phenomena. However,
extinction by humans today
is becoming much more
rapid.
The rapid loss of species today is estimated by some
experts to be between 100 and 1,000 times higher than
the natural extinction rate, while others estimate rates as
high as 1,000-11,000 times higher.
Habitat Degradation
Habitat loss and degradation affect 86%
of all threatened birds, 86% of mammals and
88% of threatened amphibians
Climate change/Global Warming
John W. Williams from UW-Madison suggests that changes
in regions such as the Peruvian Andes, portions of the
Himalayas and southern Australia could have a profound
impact on indigenous plants and animals
Williams and his research partners used computer models
to estimate how various parts of the world would be
affected by regional changes consistent with the IPCC's
climate models.
Their findings indicated that “By the end of the 21st century,
large portions of the Earth’s surface may experience
climates not found at present and some 2th century
climates may disappear.”
Their studies also suggest isolated climates such as the
Peruvian Andes could change drastically enough to lead
to species extinctions.
The climate change might also create new climates,
providing new opportunities for other species to thrive,
Williams said.
Regions where
novel climates are
expected to form in
tropical and
subtropical regions
include the western
Sahara,
southeastern U.S.
and eastern India.
Where and what are hotspots?
“The concept of biodiversity hotspots was penned by British ecologist Norman Myers in 1988 as a means to address the dilemma of identifying the areas most important for preserving species.” (national geographic)
Hotspots are included in 6 continents excluding Antarctica.
Hotspots are heavily distributed along shore lines and near the equator.
Hotspots are effected by many factors including
Logging
Agriculture
Hunting
Climate change
Government
Hotspots can be added and removed from the classification of “hotspot” by what recovery or lack of prevention is taking place in each area.
What is required to be considered a
hotspot
“The region must support at least 1,500
plant species found nowhere else in the
world, and it must have lost at least 70
percent of its original habitat.”
Interactive maps
http://www.biodiversityhotspots.org/xp/Hot
spots/home/interactive_map.xml
http://www.zeroextinction.org/pointmapper/
azefiles/index.html
What is Biodiversity? Biodiversity is the variation of taxonomic life
forms for a given biome or ecosystem
Boosts Ecosystem productivity
Measure of the health of a biological system
Benefits of Biodiversity
Food and drink
Medicines
Industrial materials
Ecological services
Leisurely, cultural, and
aesthetic values
Causes of Biodiversity Loss
Pollution
Loss of tropical forest
Spread of urban areas
Warfare
Large dam construction
Road building
Tourism
Loss of traditional
lifestyles
Consequences of Biodiversity Loss
Loss of food
Decrease in biomass
Collapse of food web
Loss of keystone species
Reduction of ecosystem efficiency and community productivity
Loss of medicinal supplies
Increased vulnerability of species to disease and predation
CropsMonoculture of crops lets the yield
become susceptible to pests or viruses
75% of crop varieties are extinct
Due to the spread of modern agriculture
Tropical Forest Cutting
Cover 13% of Earth
Home to 50% of all known plant and animal
species
FAO reports 15.4 million hectares are
destroyed annually
The Convention on Biological
Diversity
Mission Statement
“The objectives of this convention are the
conservation of biological diversity, sustainable
use of its components and the fair and equitable
sharing of the benefits arising out of the
utilization of genetic resources.”
Since it was adopted at the Earth Summit in Rio de Janeiro in 1992,
189 countries have signed and implemented it. The United States
signed it in 1993 but has yet to put it into action still today