Evolution
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0
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4.5
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today
Billions of years ago
• Formation of Earth’s crust, atmosphere and oceans
Evolution
Evolution
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Evolution
4.5
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today
Billions of years ago
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2
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• Single-cell prokaryotes form in the sea
-Bacteria
-Archaea
• Single-cell prokaryotes form in the sea
• Single-cell eukaryotes form in the seas
-Amoebae
-Ciliates
-Flagellates
-Heliozoa
Cyanobacteria
2 Amoeba
Credit: Micrographia
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1
Billions of years ago
0
0
today
Billions of years ago
• Formation of Earth’s crust, atmosphere and oceans
• Small organic molecules form in the sea
• Large organic molecule form in the sea
• First protocells form in the sea
4.5
today
Billions of years ago
• Formation of Earth’s crust, atmosphere and oceans
• Small organic molecules form in the sea
• Large organic molecule form in the sea
• First protocells form in the sea
• Formation of Earth’s crust, atmosphere and oceans
• Small organic molecules form in the sea
• Large organic molecule form in the sea
• First protocells form in the sea
Evolution
0
Evolution
today
4.5
4
3
2
Credit: Micrographia
1
Billions of years ago
• Formation of Earth’s crust, atmosphere and oceans
• Small organic molecules form in the sea
• Large organic molecule form in the sea
• First protocells form in the sea
• Formation of Earth’s crust, atmosphere and oceans
• Small organic molecules form in the sea
• Large organic molecule form in the sea
• First protocells form in the sea
• Single-cell prokaryotes form in the sea
• Single-cell eukaryotes form in the seas
• Multicellular organisms form in the seas, later on land
• Single-cell prokaryotes form in the sea
• Single-cell eukaryotes form in the seas
• Multicellular organisms form in the seas, later on land
Red algae
Credit: Berkeley, Palomar College
Red algae
Humans
0
today
Credit: Berkeley, Palomar College
Evolution:
Homonids
4.5
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Billions of years ago
0
how?
Evolution: Natural selection
today
• genetic variability
• traits must be heritable
• trait must lead to differential reproduction
Source: Reed et al., PLOS Biology
Evolution: Natural selection
how?
Structural
adaptations
Greater Koa-finch
Kuai Akialaoa
Amakihi
Kona Grosbeak
• genetic variability
• traits must be heritable
• trait must lead to differential reproduction
- leads to adaptations: heritable traits that enable
survival and reproduction
- structural, behavioral/sexual, physiological
Crested Honeycreeper
Akiapolaau
Maui Parrotbill
Apapane
finch ancestor
Evolution: Genetic variation
how?
• mutations: random changes in the structure or # of
DNA molecules in a cell that can be inherited by
offspring
Evolution: Genetic drift
how?
• random selection
• allows maladaptive traits in small populations
- probability
Worms of different color
over 4 generations:
- chance
Evolution
Loss of Biodiversity
• Large gene pool
- Increases biological fitness of the species
Confirming the Global Extinction Crisis
• Small gene pool
- Fewer traits for natural selection
- Genetic drift has significant affects
- Increased potential of extinction
London, Washington, Geneva, Ottawa
Thursday, 28 September 2000
(Embargoed 17.00h GMT
Hunted to near extinction,
30,000 to 1,000 in 1900
Extinction
• Background rate of extinction
-Natural process
- species divergence, migration or extinction
-due to
- Small changes in climate/habitat
- Depleted resources
- Species competition
Past:
10-100 species per year (from the fossil record)
Extinction
• Mass extinction (5)
- Extinctions occur all over the world
- Several types of species go extinct
- Clustered in a short amount of geologic time
(a few million years)
A call for international action as the most
authoritative global assessment of species loss is
released
“All available evidence points to a sixth major
extinction event currently underway. Unlike
the previous five events, which were due to
natural disasters and planetary change the
current loss of biodiversity is mainly due to human
activities.”
-UNEP State and Trends of the Environment, 2007
Extinction
• Background rate of extinction
-Natural process
- species divergence, migration or extinction
-due to
- Small changes in climate/habitat
- Depleted resources
- Species competition
Past: 10-100 species per year (from the fossil record)
Today: 30,000 species per year today
Extinction
• Mass extinction
Ordovician-Siluran extinction
- Extinctions occur all over •the
worldchange: drop in sea
Climate
- Several types of species go
extinct
level
as glaciers formed, then
- Clustered in a short amount
of sea
geologic
rising
levelstime
as glaciers
(a few million years) melted
• Death Toll: 25% marine families
Extinction
• Mass extinction
- Extinctions occur all over the world
- Several types of species go extinct
Late Devonian
- Clustered in a short amount of geologic time
• Unknown cause
(a few million years) • Death Toll: 22% marine families
Extinction
• Mass extinction
- Extinctions occur all over the world
End Triassic
extinction
- Several types of species
go extinct
Massive lava floods and global
- Clustered in a short•amount
of geologic time
warming
(a few million years)
• Death Toll: 22% of marine families
Extinction
• Background rate of extinction
-Natural process
- species divergence, migration or extinction
-due to
- Small changes in climate/habitat
- Depleted resources
- Species competition
Past: 10-100 species per year (from the fossil record)
Today: 30,000 species per year today
Extinction
• Mass extinction
Permian-Triassic extinction
Comet
orworld
asteroid impact (direct
- Extinctions occur all• over
the
evidence
has not been found) or
- Several types of species
go extinct
flood volcanism and related loss
- Clustered in a short amount of geologic time
of oxygen in the seas
(a few million years)
• Death Toll: 95% of all species
Extinction
• Mass extinction
extinction
- Extinctions occur allCretaceous-Tertiary
over the world
• Several-mile-wide asteroid on
- Several types of species go extinct
Yucatan Peninsula
- Clustered in a short•amount
of geologic time
Death Toll: 16% marine families,
(a few million years)
18% land vertebrate families,
including the dinosaurs
Species status
EXTINCT (EX) no reasonable doubt that the last individual has died.
EXTINCT IN THE WILD (EW) only to survive in captivity or as a
naturalized population well outside the past range
CRITICALLY ENDANGERED (CR) extremely high risk of extinction
ENDANGERED (EN) very high risk of extinction
VULNERABLE (VU) high risk of extinction
NEAR THREATENED (NT) likely to qualify for a threatened category
in the near future
LEAST CONCERN (LC) evaluated but does not meet above criteria
Source: www.iucnredlist.org
The status of species
Species status: Global
• International Union for the Conservation of Nature
and Natural Resources (IUCN)
• 2007 Red List
– identifies 41,415 species in need of conservation
– 16,119 threatened for extinction
Source: www.iucnredlist.org
The status of species
Source: 2007 IUCN Red List
The status of species
Source: 2007 IUCN Red List
Source: 2007 IUCN Red List
Species status: National
Species status: State
• US Fish & Wildlife Service:
Threatened and Endangered
Species System (TESS)
– 1355 endangered and threatened
species in the US
• WA Dept of Fish & Wildlife: Species of Concern list
–
–
–
–
–
163 Species of Concern
Recovery activities and recovery plans
Status Reports
Priority habitats
Publications
Western Gray Squirrel
Source: http://ecos.fws.gov/tess_public/
Source: http://wdfw.wa.gov/wildlife/management/endangered.html
Species Threats
Species status: State
Lynx
Pygmy rabbit
Sandhill Crane
Sea Otter
Western Pond Turtle
Threats
1. Habitat Destruction
Affects:
• 89% of threatened birds
• 83% of threatened mammals
• 91% of threatened plants
• Agriculture (farms and plantations)
• Extraction (Mining, fisheries, logging, harvesting)
• Development (industry, housing)
Passenger Pigeon, 1914
Several billion lived in
western forests
Threats
2. Invasive species
Threats
1. Habitat Destruction
• Agriculture (farms and plantations)
Giant Panda
1600 in the wild
Affects:
• 30% of threatened birds
• 5% of threatened plants
• Most common cause of
extinction of bird species
on islands after 1800
Threats
3. Pollution
Bioaccumulation
• Increasing chemical
concentration in first
organism in a food chain
Biomagnification
• Increasing chemical
concentration in
successive trophic levels
Dodo, pigeon family
Flightless bird
Native to Mauritius
DDT passed up the food web
Threats
Threats
3. Pollution
4. Over-exploitation
• Hunting
• Collecting
• Fisheries by-catch
• Trade
Affects:
• 37% of threatened birds
• 34% of threatened mammals
• 8% of threatened plants
• 8% of threatened reptiles
National Wildlife Federation
PCB’s in Puget Sound
California Condor
1983, 30 birds in the wild
Lead poisoning, habitat destruct.
Blue whale
Cause: Whaling
Current moratorium
Great Auk, 1844
Slaughter for food,
fat, feathers
MEDIA, POLLUTION PUGET SOUND:
http://seattlepi.nwsource.com/specials/brokenpromises/287994_marinedesert09.asp
Protecting wild species: Reserves
Threats
5. Climate change
• Sanctuaries
• 12% of Earth protected in reserves
• “15-37% of a sample of 1,103 land plants and
animals would eventually become extinct as a result
of climate changes expected by 2050”
Thomas et al., Nature, 2004
• Bleaching of coral reefs
- Affected 20-90% of coral reefs around Caribbean
(depending on country) 2005
• Loss of sea ice for polar bears
- 20,000 bears today
- Drop by 22% since 1980
Pelican Island was the
nation’s first wildlife refuge
Protecting wild species: Hotspots
Protecting wild species: Isolation
•
•
•
•
•
Gene banks
Botanical gardens
Farms
Zoos
Aquariums
Protecting wild species: Legislation
U.S. Endangered Species Act
• Forbids federal agencies to carry out / fund projects
that would jeopardize endangered species
• Illegal for Americans to engage in commerce
associated with hunt / kill / collect endangered or
threatened species
• Controversial - is it enough?