BIOSPHERE INTEGRITY Flashcards
Planetary Boundary & Control Variables
Control Variables:
* Genetic Diversity: Measure of variation in the genes of a population.
* Functional Diversity: The variety of ecological functions performed by organisms.
Planetary Boundary:
* Extinction Rate: Aiming for fewer than 1 extinction per million species per year (E/MSY).
* Biological Intactness Index (BII): A goal to maintain it at 90% or above, assessed geographically.
Ecosystem Functions and Services
Ecosystem Functions:
* Flow of Energy and Nutrients: Processes like productivity, decomposition, and cycling.
* Species Interactions: Interplay between different organisms in an ecosystem.
Ecosystem Services:
* Provisioning: Providing resources like food, fuel, and water.
* Regulating: Maintaining climate, controlling floods, storing carbon.
* Supporting: Enabling ecosystem processes.
* Cultural: Providing aesthetic, spiritual, and recreational value.
Life in the Biosphere Organization
Ecosystem Definition:
* Integrated System: Biotic and abiotic components working together.
Arbitrary Spatial Boundaries:
* Nested Structures: Ecosystems exist within larger ecosystems.
Biosphere, biome
Community, population, individual
Ecosystem
Trophic Levels and Energy Relationships
- Energy Flow Processes:
- Solar Radiation: Drives photosynthesis, the basis of energy flow.
Primary producers (autotrophs) are plants and photosynthetic bacteria – the lowest trophic level
Secondary producers (or primary consumers; herbivores) feed on plants
Tertiary producers (or secondary consumers; carnivores) feed on herbivores
Quaternary producers (or tertiary consumers; top carnivores) feed at the apex of the food web
Energy is passed through food chains/webs, and ultimately through entire ecosystems in this way…
Key Definitions:
Apex Predator, Habitat, Niche, Keystone Species
- Apex Predator: Top-level predator, e.g., a grey wolf.
- Habitat: The specific environment where a species resides.
- Niche: Role of a species in its ecosystem.
- Keystone Species: A species disproportionately affecting its environment, When a keystone species is removed, the ecosystem may change drastically, even if the species removed was a “small” part of the entire ecosystem
Trophic Cascade:
Occurs when the impact of a predator on its prey affects one or more trophic level.
• When the apex predator is removed, the lack of population control at the next trophic level down can affect the populations at the trophic level below.
• Trophic cascades must occur across a minimum of three trophic levels (e.g. secondary consumer, primary consumer, and producer).
• Trophic cascades can also happen from the bottom up; for example, the removal of a producer may affect population sizes in the trophic levels above it
Biodiversity and Ecosystem Resilience
Biodiversity Definition:
* Variation in Life: Genetic, species, and ecosystem diversity.
* Enhanced Resilience: Diverse ecosystems are more adaptable to change.
Mass Extinction and if we are going through one
A mass extinction is usually defined as a loss of about three quarters of all species in existence across the entire Earth over a “short” geological period of time. Given the vast amount of time since life first evolved on the planet, “short” is defined as anything less than 2.8 million years.
In contrast to the the Big Five, today’s species losses are driven by a mix of direct and indirect human activities, such as the destruction and fragmentation of habitats, direct exploitation like fishing and hunting, chemical pollution, invasive species, and human-caused global warming.
If we use the same approach to estimate today’s extinctions per million species-years, we come up with a rate that is between ten and 10,000 times higher than the background rate.
Even considering a conservative background rate of two extinctions per million species-years, the number of species that have gone extinct in the last century would have otherwise taken between 800 and 10,000 years to disappear if they were merely succumbing to the expected extinctions that happen at random. This alone supports the notion that the Earth is at least experiencing many more extinctions than expected from the background rate.
- Aichi Biodiversity Targets:
- Strategic Goals: Addressing causes, pressures, and improving the status of biodiversity.
- Importance: Recognizing the significance for human well-being.
Human Impact and Future Actions
Human Impact on Biodiversity:
* Direct and Indirect: Human activities influencing biodiversity.
* Approaching Mass Extinction: Concerns about the irreversible loss of species.
International Frameworks:
* Convention on Biological Diversity: A global agreement to protect biodiversity.
* Need for More Efforts: Recognizing the need for additional actions to preserve biosphere integrity.
