3.3 Threats to biodiversity Flashcards
What does IUCN stand for
International Union of Conservation of Nature
What did the IUCN publish and what is it
The Red List of Threatened Species
Estimated total no. of species, why is it inaccurate
7-100 million
many species are too small to be observed such as fungi and insects
Why are the majority of mammals and birds known?
They’re big
Categories in IUCN thing (7)
Data Deficient, Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, Extinct
Example of critically endangered species, discuss details
3-toed sloths are endemic to Escudi de Verguas island in Panama (Central America). Fewer than 100 3-toed sloths left in the world.
Sloths are a keystone species, they disperse fruit seeds. Their fur houses many insects and animals (symbiosis)
Example of previously endangered but recovered species, discuss details
Giant pandas went from endangered to vulnerable thanks to repopulation of bamboo forests.
Giant pandas are flagship species, small role in the ecosystem (seed dispersal). However high economic value due to ecotourism
Example of extinct species and discuss details
Mammoths went extinct in 1650 BC due to food scarcity. Keystone species and extinction worsened climate change: est. 0.1C of global warming.
- increase in wildfires since there are fewer herbivores to eat leaves, so leaves fueled fires
- mammoth no eat trees -> tree overgrowth replacing grasslands and absorbing more solar energy
Factors affecting if species are prone to extinction (6)
population size
geographical range
degree of specialisation
distribution
reproductive potential
trophic level
What are species specialists & concerns
Species highly adapted to specific habitats, food supplies. Prone to extinction due to lack of adaptability
What is the conflict regarding biodiversity in LEDCs
More tropical biomes in LEDCs, conflict between exploitation and sustainable development due to need for economic development
What is Minimum Viable Population Size
required size for species to survive in the wild. Varies based on species
Factors affecting biodiversity (3)
Successional stage, ecosystem complexity, limiting factors (lack of abiotic resources)
Factors that reduce biodiversity
Natural hazards & disasters, anthropic causes
List and explain anthropic causes of loss of biodiversity
Habitat destruction
- main cause, deforestation, urbanisation etc
Habitat fragmentation
- division of an area into fragments in URBANISATION - increases to edge effect
Invasive species
- increases competition
Pollution
- damages habitats and health of populations
Overexploitation
- capturing more organisms than the population can naturally recover from at an adequate rate
