6 Flashcards
What is the greenhouse effect (GHE)?
A natural phenomenon where greenhouse gases trap heat in the atmosphere, keeping Earth’s surface above freezing—now accelerated by human activities
What human activity has most accelerated the greenhouse effect?
Burning fossil fuels.
What is the current atmospheric CO₂ concentration compared to pre-industrial levels?
Over 400 ppm today, compared to 260–280 ppm pre-industrially.
Why is climate change a biodiversity threat?
It alters habitats, triggers extreme weather, changes species distributions, and can lead to extinctions.
What historical events link climate change and mass extinction?
Events like the Permian and Cretaceous extinctions were tied to drastic climate shifts, likely caused by CO₂ pollution or impact events.
What does the “O” in HIPPO stand for?
Overexploitation, including overhunting, overfishing, and excessive resource extraction.
What is overexploitation?
Harvesting natural resources at a rate that exceeds the capacity for replenishment.
What is a trophic cascade in the context of overexploitation?
The removal of key species (especially keystone species) causes a ripple effect throughout the food web.
What is “exceptionally unnecessary” overexploitation?
Killing or capturing species for decorative, traditional, or luxury purposes rather than subsistence (e.g., rhino horns, tiger parts).
What is the significance of the term economic extinction?
When a species is no longer profitable to harvest, often preceding biological extinction.
What is Maximum Sustainable Yield (MSY)?
The largest number of individuals that can be harvested without preventing population recovery.
Why can MSY models be flawed?
They rely on assumptions about population growth and ignore other mortality factors and environmental variability.
Give an example of MSY miscalculation.
The Orange Roughy fishery in New Zealand collapsed due to underestimating the species’ lifespan and slow reproduction.
How did Viagra inadvertently help wildlife?
It reduced demand for animal-based aphrodisiacs like tiger penis soup and seal genitals.
Why do many overexploited populations not recover?
Due to low genetic diversity, reproductive failures, and continued pressure even after economic or regulatory intervention (e.g., Atlantic cod collapse).
