Communities can be described and compared through diversity indices which take into account the number of species and their distribution. Low diversity indices could indicate pollution, eutrophication, or recent colonization. Quantifying biodiversity is important for conservation efforts to identify and protect high biodiversity areas. Assessing changes in biodiversity over time helps evaluate human impacts on communities.

1. https://clipartstation.com/wp-content/uploads/2018/09/biodiversity-clipart-4.jpg
3.1. An introduction to biodiversity
Miltiadis-Spyridon Kitsos
Platon IB Diploma

2. Knowledge and understanding
• Biodiversity is a broad concept encompassing the total diversity of living systems,
which includes the diversity of species, habitat diversity and genetic diversity.
• Species diversity in communities is a product of two variables: the number of
species (richness) and their relative proportions (evenness).
• Communities can be described and compared through the use of diversity indices.
When comparing communities that are similar, low diversity could be indicative of
pollution, eutrophication or recent colonization of a site.
The number of species present in an area is often indicative of general patterns of
biodiversity.
•Habitat diversity refers to the range of different habitats in an ecosystem or biome.
•Genetic diversity refers to the range of genetic material present in a population of a
species.

3. Knowledge and understanding
• Quantification of biodiversity is important to conservation efforts so that areas of
high biodiversity may be identified, explored, and appropriate conservation put in
place where possible.
•The ability to assess changes to biodiversity in a given community over time is
important in assessing the impact of human activity in the community.
Applications and skills
• Distinguish between biodiversity, diversity of species, habitat diversity and genetic
diversity.
•Comment on the relative values of biodiversity data.
•Discuss the usefulness of providing numerical values of species diversity to
understanding the nature of biological communities and the conservation of
biodiversity.

4. 3.1. U1. Biodiversity is a broad concept encompassing the total diversity of living systems, which
includes the diversity of species, habitat diversity and genetic diversity.
Which of the two systems has a higher diversity?Warm up
Now? what do you think?

5. 3.1. U1. Biodiversity is a broad concept encompassing the total diversity of living systems, which
includes the diversity of species, habitat diversity and genetic diversity.

6. 3.1. U2. Species diversity in communities is a product of two variables: the number of species
(richness) and their relative proportions (evenness).
Community 1 Community 2
🌲 4 2
🌳 4 1
4 2
4 11
Can you tell the differences in the richness and evens between the two communities?

7. 3.1. U1. Biodiversity is a broad concept encompassing the total diversity of living systems, which
includes the diversity of species, habitat diversity and genetic diversity.
Spatial gradient of mammalian species richness in the continental
New World for cells defined by 2.5' parallels and meridians.
jstor.org/stable/30033777?seq=1
https://www.philpoteducation.com/pluginfile.php/1180/mod_book/chapter/1088/10.1.3a.jpg
The larger the population the larger the genetic diversity. The higher
the number of populations in different places, the bigger the genetic
diversity.
Tropical rainforests are characterised by habitat diversity. Can you think
why?
https://imgs.mongabay.com/wp-content/uploads/sites/20/2019/08/18144629/7-tp.jpg

8. 3.1. U3. Communities can be described and compared through the use of diversity indices. When
comparing communities that are similar, low diversity could be indicative of pollution, eutrophication
or recent colonization of a site.
Biodiversity is often used as a measure of ecosystem health, as high biodiversity usually
equates with high ecosystem health.
https://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/17064077/f1_cleland_ksm.jpg
For the sake of this example let's assume that the blue
species has traits that allow it to survive prolonged
drought. Looking at all possible combinations of
communities containing 1, 2 or 3 species, we see that,
as the number of species being blue increases
https://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/22147230/
cleland_ksm_revised_1_2.jpg

9. 3.1. U3. Communities can be described and compared through the use of diversity indices. When
comparing communities that are similar, low diversity could be indicative of pollution, eutrophication
or recent colonization of a site.
Communities can be described and compared by the use of diversity indices
Mathematical models that take into account the number of species (richness) and the
evenness of their distribution.
Simpson’s reciprocal index in which 1 is the lowest value (when there would be just one
species) and a higher value means more diversity.
Low values of the diversity index could be evidence of pollution, eutrophication or recent
colonization of a site.
Measurements of biodiversity are repeated in the course of time as biodiversity may be
changing temporally do to succession or anthropogenic impacts. These measurements can
give us an idea on the progress of the conservation efforts.

10. 3.1. U5. Quantification of biodiversity is important to conservation efforts so that areas of high
biodiversity may be identified, explored, and appropriate conservation put in place where possible.
Changes in the species richness and evenness
in an area dominated by cushion plants, which
allow the settlement of other plant species on
them. Graph X axis, cushion density.
Read more at
Presence of cushion plants increases community diversity in the high
equatorial Andes
https://www.researchgate.net/publication/
248908090_Presence_of_cushion_plants_increases_community_diversity_in_the_high_equatorial_Andes

11. 3.1. U6. The ability to assess changes to biodiversity in a given community over time is important in
assessing the impact of human activity in the community.
Changes in the diversity of phyla and species
richness of soil microbial communities in
response to hydrocarbon pollution
Read more at
https://www.researchgate.net/publication/284278320_From_Rare_to_Dominant_A_Fine-
Tuned_Soil_Bacterial_Bloom_during_Petroleum_Hydrocarbon_Bioremediation
From Rare to Dominant: A Fine-Tuned Soil Bacterial Bloom during
Petroleum Hydrocarbon Bioremediation

12. 3.1. U5. Quantification of biodiversity is important to conservation efforts so that areas of high
biodiversity may be identified, explored, and appropriate conservation put in place where possible.
• Mostly located in tropical forests
• Nearer the tropics
• Threatened by human activities
A biodiversity hotspot is a region with a high level of biodiversity that is under threat from
human activities.
• Only 2.3% if land density
• Close to overpopulated areas
Features
https://www.youtube.com/watch?v=RaQBaVeEbW8
https://youtu.be/y6-h56B5n9U
https://databasin.org/maps/new#datasets=23fb5da1586141109fa6f8d45de0a260

13. References
Andrew, Davis, et al. Pearson Baccaularete Environmental Systems And Socieities For The Ib Diploma.
Rutherford, Jill. Environmental Systems and Societies. Oxford University Press, 2015.