Biodiversity is the variety of life on Earth, from genes inside a population to species in a forest to entire ecosystems such as wetlands, coral reefs, and grasslands. It matters because living systems are connected through food webs, nutrient cycles, pollination, and habitat formation. High biodiversity often makes ecosystems more stable, productive, and able to recover after disturbance.
It also supports human needs such as food, medicine, clean water, fertile soil, and climate regulation.
Biodiversity works at several levels that interact with one another. Genetic diversity helps populations adapt to disease, climate shifts, and changing resources, while species diversity gives ecosystems more ways to perform important functions. Ecosystem diversity provides a range of habitats and processes that support many forms of life.
Major threats include habitat loss, invasive species, pollution, overharvesting, and climate change, which can reduce resilience and cause cascading effects through ecosystems.
Key Facts
- Biodiversity includes genetic diversity, species diversity, and ecosystem diversity.
- Species richness = the number of different species in an area.
- Relative abundance = the proportion of individuals that belong to each species.
- Higher genetic diversity usually increases a population's chance of adapting to environmental change.
- Ecosystem services include provisioning, regulating, cultural, and supporting services.
- Extinction rate = number of species lost per unit time, often increased by human-driven habitat loss and climate change.
Vocabulary
- Biodiversity
- Biodiversity is the variety of living things at genetic, species, and ecosystem levels.
- Genetic diversity
- Genetic diversity is the variation in inherited traits among individuals within a population or species.
- Species richness
- Species richness is the number of different species found in a given area.
- Ecosystem services
- Ecosystem services are the benefits people receive from nature, such as pollination, clean water, food, and climate regulation.
- Resilience
- Resilience is an ecosystem's ability to recover after a disturbance such as fire, drought, disease, or human impact.
Common Mistakes to Avoid
- Counting only the number of species, because biodiversity also includes genetic diversity, relative abundance, and ecosystem variety.
- Assuming all ecosystems with the same species richness are equally diverse, because an ecosystem dominated by one species is less even and often less stable.
- Thinking extinction affects only one species, because species are connected through food webs, competition, pollination, seed dispersal, and habitat relationships.
- Treating ecosystem services as optional benefits, because they support essential human needs such as crop production, water filtration, soil formation, and disease regulation.
Practice Questions
- 1 A meadow contains 12 plant species, and a nearby lawn contains 4 plant species. How many more plant species does the meadow have, and what is the ratio of meadow species richness to lawn species richness?
- 2 In a pond sample of 100 organisms, 40 are species A, 30 are species B, 20 are species C, and 10 are species D. What is the relative abundance of each species as a percent?
- 3 A forest with many tree species is struck by a disease that kills one common tree species, while a nearby plantation has only that tree species. Explain which system is likely to be more resilient and why.