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

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Presentation on theme: "Available at Extinction: past, present, future Gwen Raitt BCB 705: Biodiversity."— Presentation transcript:

1 Available at http://planet.uwc.ac.za/nisl Extinction: past, present, future Gwen Raitt BCB 705: Biodiversity

2  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 0NISL  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). What is Extinction?

3  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 Populations

4  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. Mechanisms of Extinction in Single Populations

5  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. Metapopulations

6  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 Mechanisms of Extinction in Metapopulations

7  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) Google  gg  Google (visited link) Background Extinction and Extinction Rates

8  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). Mass Extinctions

9  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). End Ordovician Mass Extinction

10  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) Late Devonian Mass Extinction

11  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). End Permian Mass Extinction

12  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) End Triassic Mass Extinction

13  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) End Cretaceous Mass Extinction

14  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) Present Mass Extinction

15  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) Human Extinction?

16  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 0NISL  Keep within the frame … this ensures it will not get clipped when projecting.  Use Bullet Points as indicated (Square colour is 128 128 0 ) Conclusions – the Future?


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