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Extinction: past, present, future

Extinction: past, present, future. Gwen Raitt. BCB 705: Biodiversity. What is Extinction?. Dark green font Arial at least 18 point this colour is 70 70 0

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Extinction: past, present, future

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  1. Extinction: past, present, future Gwen Raitt BCB 705: Biodiversity

  2. What is Extinction? • Dark green font Arial at least 18 point this colour is 70 70 0 • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Extinction is the result of failing to adapt to environmental changes (Futuyma 1998). Mechanisms of extinction act at the population/metapopulation level (Barbault & Sastrapradja 1995).

  3. Populations • A population is a group of individuals of a given species living in a specific geographic area at one time. • Population size and survival depend on: • The availability of resources • The amount of suitable habitat • Predation/parasitism • Disease • Social interactions

  4. Mechanisms of Extinction in Single Populations • Population extinction is certain if, in the long term, the mortality rate is higher than the birth rate. • Extinction mechanisms act by affecting the mortality and birth rates. The mechanisms may be grouped into four categories for single populations: • Allee effects • Demographic uncertainty • Environmental uncertainty • ‘Natural’ catastrophes • Loss of genetic diversity • Mechanisms may interact, compounding the effect on the population. • Population size is critical to survival.

  5. Metapopulations • A metapopulation is made up of a number of spatially separated, extinction-prone local populations (or subpopulations) that are linked by migration. Other than the classical metapopulation, the following types are recognized: • Mainland-island metapopulations • Source-sink metapopulations • Non-equilibrium metapopulations. • Metapopulation survival depends on: • Local population survival • Unoccupied suitable habitat at suitable distances • Sufficient migration for colonization of unoccupied habitat to occur.

  6. Mechanisms of Extinction in Metapopulations • Extinction of a metapopulation is certain if the extinction rate of local populations exceeds the rate at which new populations are established. • Local population extinction mechanisms are those of single populations. • The mechanisms acting at the metapopulation level may be grouped into two categories: • Colonization-extinction uncertainty • Regional uncertainty

  7. Background Extinction and Extinction Rates • Extinction is natural (Freeman & Herron 1998). The normal extinction rate is known as background extinction or the background extinction rate (Futuyma 1998). • Background extinction rates are constant within clades but vary greatly between clades (Freeman & Herron 1998). • Google (new link, not visited) • gg • Google (visited link)

  8. Mass Extinctions • Extinction events were used to demarcate the geological time periods (Leakey & Levin 1995). • Click on the text box and right click on the mouse and a menu should appear and you select the Copy • The move to the slide you wish to paste to and right click on the mouse and a menu should appear and you select the Paste • Raup & Sepkoski (1984) suggest that mass extinction events occur periodically (Futuyma 1998).

  9. End Ordovician Mass Extinction • Second largest of the ‘Big Five’ mass extinctions (Futuyma 1998). • ddd • Possible causes include a drop in temperature and a drop in sea level (Futuyma 1998).

  10. Late Devonian Mass Extinction • Dark green font Arial at least 18 point this colour is 70 70 0 • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

  11. End Permian Mass Extinction • Biggest of the ‘Big Five’ mass extinctions (Futuyma 1998). • Marine diversity lost 51 % of the families of skeletonised invertebrates (Futuyma 1998). • On land the extinction was less severe, some families of amphibians and therapsids were lost, some insect orders were lost and the dominant plants changed (Futuyma 1998). • Possible causes include a variable climate, a drop in sea level and high volcanic activity (Futuyma 1998).

  12. End Triassic Mass Extinction • Loss of marine ammonoids and bivalves (Futuyma 1998). • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

  13. End Cretaceous Mass Extinction • Dark green font Arial at least 18 point this colour is 70 70 0 • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

  14. Present Mass Extinction • There is evidence that the extinctions on New Zealand and the Pacific Islands after human colonization were ultimately caused by humans (Caughley & Gunn 1996). • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

  15. Human Extinction? • Dark green font Arial at least 18 point this colour is 70 70 0 • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

  16. Conclusions – the Future? • Dark green font Arial at least 18 point this colour is 70 70 0 • Use animation and the effects of BLINDS for TEXT and DISSOLVE for IMAGES– they are quick and effective and bring in by paragraph and then dim after mouse click to a mid grey colour 150 150 150 • Give each slide a header … there is space in the top and it also uses the colour 150, 150, 150 this uses Word Art and can be stretched. Use VIEW / MASTER/ SLIDE MASTER to access • If you need to hyperlink such as this is the URL for NISL if you use this as a template the colour is already set and is 96 132 113. For a visited Hyperlink use this colour which is 204 102 0 • Keep within the frame … this ensures it will not get clipped when projecting. • Use Bullet Points as indicated (Square colour is 128 128 0 )

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