1. Loss of Biodiversity EXTINCTION - the disappearance of a species
Extinctions have been occurring constantly at a low 'background rate', usually matched by the rate at which new species appear - resulting in an overall increase in biodiversity
Imagine a world without extinction -it would be really crowded!!

2. Extinction Examples
‘Cambrian Explosion’ (rapid increase in biodiversity 500 million years ago) was followed by a small extinction including loss of many trilobites (¯diversity)
cause unknown - possibly sea level change

3. 1. End of Ordovician (440 mya) probably due to glaciation
Mass Extinctions
There have been 5 major extinctions since the beginning of life 3.5 billion years ago
1. End of Ordovician (440 mya) probably due to glaciation
2. Late Devonian (365 mya) possibly due to global cooling since many warm water species were lost
Over 500, million years

4. 3. Permian (250 mya) - biggest extinction
estimated that as many as 96% of all marine species were lost and on land, 3/4 of all vertebrate families became extinct
Possible causes
continents merging to form Pangea disturbing marine and terrestrial habitats
volcanic eruptions - ash and CO2 released caused global warming

5. 4. Late Triassic (200 mya) - loss of about 1/4 of families due to climate change (possibly increased rainfall)
This loss of biodiversity provided opportunities for dinosaurs to exploit

6. 5. Cretaceous-Tertiary (K-T) - extinction of half of all marine species, many terrestrial plants and animals including the dinosaurs (65 mya)
Possible causes:
Impact hypothesis - meteorite 10 km in diameter collided with the earth disrupting ecosystems
Volcanic activity in “India” released material that blocked sunlight Ô earth became cooler

7. Non-human causes of extinction
Volcanic events
Ocean temperature change
Sea level changes
Meteorites
Glaciation
Global climate change
Competition / predation

8. Human causes of extinction/loss of biodiversity – HIPPO
Habitat destruction
Introduced species
Pollution
Population
Over consumption

9. Habitat destruction Degradation Fragmentation Loss
e.g. stream siltation caused by deforestation
Fragmentation
e.g.highways through national parks
Loss
e.g. Pasakpoo slopes in Calgary (Bronwyn)
e.g. new hospital in Edinburgh (Fiona)

10. Genetically modified species
Introduced species
Non-native species
e.g. green crab, zebra mussel, ctenophore in Mediterranean Sea
Genetically modified species

11. Pollution Air Water Land Major sources:
Fossil fuels e.g. Shoreham Power Station
Domestic waste
Industrial waste
Manufacturing processes
Agriculture

12. Population
With the global population increasing at a rate of 3 people per second there is:
Increasing use of resources
Increasing habitat destruction
Increasing waste production

13. Hunting, collecting, harvesting
Over consumption
Hunting, collecting, harvesting
e.g. Atlantic cod for food
e.g. sea otter for fur
Wildlife trade e.g. bear gallbladders as aphrodisiacs
Indirectly through over consumption of resources e.g. water, land

14. Are we on the verge of a sixth mass extinction?

15. Sixth mass extinction? Background extinction rate:
Ten to 100 species per year
3-5 families per million years
Mass extinction rate
> 10 families per million years
In past 200 years the extinction rate has been 20 to 50 (to 10,000) times greater than background mostly due to human activities (HIPPO!)

16. Sixth mass extinction?
15,000 to 100,000 species extinctions every year (Estimated)
Estimated loss of 27,000 species per year from rainforests alone
If we assume that there are 10 million species on the planet, it would only take about 560 years for 95% to go extinct at the present rate

17. Does it matter if there is a sixth extinction?
Won’t biodiversity recover?
Do we value biodiversity?

18. Categories (IUCN + COSEWIC)
Extinct - no reasonable doubt that the last individual has died (no records in 50 years)
Endangered - a species facing imminent extinction or extirpation
Extirpated - a species that is gone from an area but still exists elsewhere
Threatened - a species likely to become endangered if the factors affecting its vulnerability are not reversed
Vulnerable - at risk due to declining population but not threatened
Unknown - insufficient data
Not at risk - species was evaluated and found not to be at risk

19. Red list - include extirpated, endangered or threatened species
BC lists
Red list - include extirpated, endangered or threatened species
e.g. Steller sea lion, double crested cormorant
Blue list - includes vulnerable species (species of concern)
e.g. grey whale, great blue heron
Yellow list - includes species which are uncommon or show declining populations
e.g.river otter, belted kingfisher

20. Characteristics of vulnerable species
Small population size - island species
Small population size - species with limited habitats
Extremely specialized species
Species with low reproductive potential
Species that require large territories
Species with limited dispersal ability

21. Vulnerable species - continued
Migratory species
Species that are economically valuable or hunted for sport
Predators
Species that are vulnerable to pollution
Species that are incompatible with civilization

22. Species approach to conservation
Strengths
Weaknesses

23. Coelacanth
thought to have vanished from the fossil record around 70 million years ago
living coelacanths were found living off the Comoro Islands in the Indian Ocean in 1938

24. rule for the genetic health of populations - population of 50 or more is adequate for the short term only, and one of 500 is needed to keep the species alive and healthy into the distant future - E.O. Wilson “Diversity of Life”