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Description
Flashcards by Shareef Akbari, updated more than 1 year ago
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Created by Shareef Akbari
over 7 years ago
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| Question | Answer |
| What is the area effect? | As area increases, the number of species increases |
| What are the two factors that are the main determinants of species richness on an island and how do they explain species richness? | 1. Area of island: Extinction rates are lower on large islands 2. Distance from the mainland: Easier for colonisers to find the island if it's close and higher chance of survival getting to it. Also, the closer the island is, the more likely immigrant individuals can resue a species on the brink of extinction. |
| Explain the trends in this graph | 1. Immigration rates decrease as species richness increases because, with more species, there is an increased chance that that species has already been there. 2. Extinction rates increase with species richness due to increased competition 3. The green circle is the S* equilibrium, which is the number of species where immigration and extinction rates are the same and represents the number of species expected on the island. |
| Explain the effect of decreased distance on S*. | S* increases as immigration rates increase because immigration rates are inversely proportional to the distance from the mainland. |
| Explain the effect of decreased island size on S* | Extinction rates increase as island size decreases, so S* decreases. |
| What is the McArthur equation? | S=cA^z log(S)=log(c)+zlog(A) S=species richness z=slope A=area |
| What is the implication of the McArthur equation? | The McArthur equation results in the following graph. What this implies is that as island area approaches infinite, species richness reaches some limit. In conservational biology, this means that if you destroy enough land to bring the graph into the linear part, in order to bring back species richness, you only need to restore a fraction of this land. |
| What were Diamond's arguments in the SLOSS debate? | 1. Larger parks are better 2. Higher connectivity is better as it emulates larger size 3. Single large is better because of decreased extinction rates. |
| What were Simberloff's arguments during the SLOSS debate? | 1. Several small parks are better because each park would be in the linear part of the richness vs area graph. Each park would therefore have more species. |
| Which is better for conservation, single large, or several small? Why? | Single large. Large parks have lower extinction rates. While it is true that several small parks have a total number of species that is higher than a single large, the goal is not to have the most species, but to conserve the species you have. Small parks have higher extinction rates and so you will lose the species you have. |
| What is a neutral ecological theory? | A theory that treats all species the same. |
| What happens to native species diversity when you fragment landscapes? | Decreases |
| What is a metapopulation? | Assemblage of local populations that are linked by colonization and extinction. |
| Describe the source sink model of metapopulation interaction. | Species move from the initial source into surrounding habitats and colonize those habitats. |
| Describe the winking patches model of metapopulation interaction. | There are several habitats that are all interconnected. Species may go extinct in some areas but will be recolonized by organisms in the other, connected habitats. Thus, species in each patch "wink" in and out of existance |
| What is the relationship between connectivity and population persistance | As connectivity increases so does population persistence. |
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