Extinction

1
Extinction
2
Extinction

• The Definition and Causes

3
What is Extinction?

• Extinction occurs when the last existing member
  of a given species dies
• In other wordsthere arent 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

4
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

5
Causes Cont.

• Habitat Degradation
• One of the most influential
• Has many causes
• Some due to humans
• Some due to other factors

6
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

7
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

8
Causes Cont.

• Predation
• Competition
• Disease
• Coextinction
• Mass Extinction
• Planned Extinction

9
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

10
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

11
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

12
Mass Extinction Diagram
13
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.

14
Mass Extinction

• Began about three-million years ago (Continental
  Glaciations).
• Hypotheses for initial extinction
• Sea level depletion vs. Temperature decrease
• Though these hypotheses arent mutually
  exclusive, they may have conspired together.

15
Mass Extinctions

• Cretaceous-Tertiary Extinction (65).
• End Triassic Extinction (200).
• Permian Triassic Extinction (250).
• Late Devonian Extinction (364).
• Ordovician-Silurian Extinction (440).
• ( millions of years ago)

16
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)

17
Natural Causes of Extinction
18
Climatic Heating and Cooling
19
Changes in Sea Level or Currents

• www.johnstonsarchive.net/spaceart/cylmaps.html

20
Asteroids

• Causes complete devastation
• Flattening and crater at
• or around impact site-hundreds of miles wide
• Reverberations felt around the world

21
Cosmic Radiation

• www.iit.edu/ipro313s/home.html

22
Acid Rain

• Kills acid intolerant
• species

23
Disease/Epidemics

• Can wipe out entire species
• Frog with fungus disease
• Killing frogs and other amphibians

24
Spread of Invasive Species
25
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
26
Human Causes of Extinction
27
Top Human Causes of Extinction

• Increased human population
• Destruction/Fragmentation of habitat
• Pollution
• Climate change/Global warming

28

• Extinctions caused by humans are generally
  considered to be a recent phenomena. HOWEVER
• In Australiaearliest humans 64,000 years ago
• extinction30,000-60,000 years ago
• In the Americas80 of large animals became
  extinct around the same time as first human
  presence there

29
(No Transcript)
30
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.
31
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.
32

• Habitat Degradation
• Habitat loss and degradation affect 86 of all
  threatened birds, 86 of mammals and 88 of
  threatened amphibians

33
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 Earths surface
may experience climates not found at present and
some 2th century climates may disappear.
34
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.
35
Extinction Hotspots
36
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.

37

• 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.

38
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.

39
Interactive maps

• http//www.biodiversityhotspots.org/xp/Hotspots/ho
  me/interactive_map.xml
• http//www.zeroextinction.org/pointmapper/azefiles
  /index.html

40
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

41
Benefits of Biodiversity

• Food and drink
• Medicines
• Industrial materials
• Ecological services
• Leisurely, cultural, and
• aesthetic values

42
Causes of Biodiversity Loss

• Pollution
• Loss of tropical forest
• Spread of urban areas
• Warfare
• Large dam construction
• Road building
• Tourism
• Loss of traditional lifestyles

43
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

44
Crops

• Monoculture of crops lets the yield become
  susceptible to pests or viruses
• 75 of crop varieties are extinct
• Due to the spread of modern agriculture

45
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

46
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

47
The Convention on Biological Diversity

• 2010 Biodiversity Target
• Members adopted a plan to significantly reduce
  the present rate of biodiversity loss at the
  global, regional and national level by the year
  2010.

48
References

• Ceballos, G., and Ehrlich, P., 2002, Mammal
  Population Losses and the Extinction Crisis
• Science, v. 296, p. 904-908.
• Fahrig, L., 2002, Effect of Habitat
  Fragmentation on the Extinction Threshold A
• Synthesis Ecological Applications, v. 12, p.
  346-353.
• Gittleman, J., The Risk of ExtinctionWhat you
  dont know will hurt you Science, v. 291.
• Petcchey, O.L., and Gaston, K.J., Extinction and
  the loss of functional diversity They Royal
• Society, p. 1721-1727.
• Rutledge, D., Lepczyk, C., Xie, J., Liu, J.,
  2001, Spatiotemporal Dynamics of Endangered
• Species Hotspots in the United States
  Conservation Biology, v. 15, p. 475- 487.
• Kent, Holsinger. "The Causes of Extinction." 27
  Aug. 2005. 12 Mar. 2007 lthttp//darwin.eeb.uconn.e
  du/eeb310/lecture-notes/extinctions/node3.htmlgt.
• Madeley, J., Warnock, K., 1995, Biodiversity A
  Matter of Extinction The challenge of protecting
  the Souths biological heritage
  lthttp//www.panos.org.uk/pdf/reports/
  biodiversity.pdfgt.
• Trombulak, Stpehen C., et. Al. 2004, Principles
  of Conservation Biology Recommended
• Guidelines for Conservation Literacy from the
  Education Committee of the Society for
• Bald Eagle. US Fish and Wildlife Service
  lthttp//www.fws.gov/endangered/i/b/msab0h.htmlgt.
• Conservation Biology Conservation Biology
  lthttp//www.conbio.org/Resources/Education/conserv
  ation_literacy_english.pdfgt.
• Extinction. Lecture by Bruce Walsh at University
  of Arizona, 1995.
• lthttp//nitro.biosci.arizona.edu/courses/EEB105/le
  ctures/extinction/extinction.htmlgt.

49
References
Trombulak, Stpehen C., et. Al. 2004, Principles
of Conservation Biology Recommended Guidelines
for Conservation Literacy from the Education
Committee of the Society for Bald Eagle. US Fish
and Wildlife Service lthttp//www.fws.gov/endangere
d/i/b/msab0h.htmlgt. Conservation Biology
Conservation Biology lthttp//www.conbio.org/Resour
ces/Education/conservation_literacy_english.pdfgt.
Extinction. Lecture by Bruce Walsh at University
of Arizona, 1995. lthttp//nitro.biosci.arizona.e
du/courses/EEB105/lectures/extinction/extinction.h
tmlgt.