Biogeographic regions Sclater Wallace Sclater-Wallace System.
CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin...
-
date post
20-Dec-2015 -
Category
Documents
-
view
231 -
download
0
Transcript of CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin...
![Page 1: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/1.jpg)
CHAPTER 53COMMUNITY ECOLOGY
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Section D: Biogeographic Factors Affecting the Biodiversity of Communities
1. Community biodiversity measures the number of species and their relative
abundance
2. Species richness generally declines along an equatorial-polar gradient
3. Species richness is related to a community’s geographic size
4. Species richness on an island depends on island size and distance from the
mainland
![Page 2: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/2.jpg)
• Two key factors correlated with a community’s biodiversity (species diversity) are its size and biogeography.
Introduction
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 3: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/3.jpg)
• The variety of different kinds of organisms that make up a community has two components.
• Species richness, the total number of species in the community.
• Relative abundance of the different species.
• Imagine two small forest communities with 100 individuals distributed among four different tree species.
1. Community biodiversity measures the number of species and their relative abundance
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 4: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/4.jpg)
• Species richnessmay be equal,but relativeabundance maybe different.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.21
![Page 5: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/5.jpg)
• Counting species in a community to determine their abundance is difficult, especially for insects and smaller organisms
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.22
![Page 6: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/6.jpg)
• Tropical habitats support much larger numbers of species of organisms than do temperate and polar regions.
2. Species richness generally declines along an equatorial-polar gradient
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 7: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/7.jpg)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.23
![Page 8: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/8.jpg)
• What causes these gradients?
• The two key factors are probably evolutionary history and climate.
• Organisms have a history in an area where they are adapted to the climate.
• Energy and water may factor into this phenomenon.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 9: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/9.jpg)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.24
![Page 10: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/10.jpg)
• The species-area curve quantifies what may seem obvious: the larger the geographic area, the greaterthe numberof species.
3. Species richness is related to a community’s geographic size
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 23.25
![Page 11: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/11.jpg)
• Because of their size and isolation, islands provide great opportunities for studying some of the biogeographic factors that affect the species diversity of communities.
• Imagine a newly formed island some distance from the mainland.
• Robert MacArthur and E. O. Wilson developed a hypothesis of island biogeography to identify the determinants of species diversity on an island.
4. Species richness on islands depends on island size and distance from the mainland
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
![Page 12: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/12.jpg)
• Two factors will determine the number of species that eventually inhabit the island.
• The rate at which new species immigrate to the island.
• The rate at which species become extinct.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 53.26
![Page 13: CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section D: Biogeographic Factors Affecting the Biodiversity.](https://reader035.fdocuments.net/reader035/viewer/2022081506/56649d415503460f94a1ba8f/html5/thumbnails/13.jpg)
• Studies of plants on many island chains confirm their hypothesis.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.27