The document defines species richness, species evenness, and species diversity. It notes that species diversity incorporates both richness and evenness. It also discusses biodiversity as the total genetic variation among organisms and some reasons for preserving biodiversity, including potential new medicines from plants, pest resistance genes in crop wild relatives, and ecosystem services from diverse ecosystems. Finally, it introduces keystone species as those that play a key role in maintaining ecosystem diversity and structure, providing sea otters and their effect on kelp forests as an example.

1. Notes: Diversity (pg 16)

2. Notes: Diversity (pg 16)
• Species Richness = The number of species in a
community

3. Notes: Diversity (pg 16)
• Species Richness = The number of species in a
community
• Species Evenness = measures how equal the
species in a community are numerically

4. Notes: Diversity (pg 16)
• Species Richness = The number of species in a
community
• Species Evenness = measures how equal the
species in a community are numerically
• Species Diversity = The number and relative
abundance of species in a community
(includes richnessANDevenness)

5. Biodiversity
• The total of all the genetically based variation
in all organisms in the biosphere

6. Biodiversity
• The total of all the genetically based variation
in all organisms in the biosphere
• Why should we be concerned about
preserving biodiversity?
1. Medicine: Plant species are the source of
many new medicines

7. Biodiversity
• The total of all the genetically based variation
in all organisms in the biosphere
• Why should we be concerned about
preserving biodiversity?
1. Medicine: Plant species are the source of
many new medicines
2. Agriculture: Wild relatives of crops can have
genes for pest or disease-resistance

8. Biodiversity
• The total of all the genetically based variation
in all organisms in the biosphere
• Why should we be concerned about
preserving biodiversity?
1. Medicine: Plant species are the source of
many new medicines
2. Agriculture: Wild relatives of crops can have
genes for pest or disease-resistance
3. Ecosystem Services: Healthy and diverse
ecosystems help maintain soil, water, and air
quality

9. Keystone Species
• Play a key role in maintaining the diversity and
structure of an ecosystem

10. Keystone Species
• Play a key role in maintaining the diversity and
structure of an ecosystem
• Example: Sea otter. Eats sea urchins, which
allows kelp forests to grow. Many species of
fish and other animals live in the kelp forest