Populations & Sustainability Flashcards
Explain the population growth curve
Phase 1 - slow growth (inital organisms reproduce)
Pahse 2 - rapid growth (breeding individuals increase cause exponential growth, no limiting factors)
Phase 3 - stable state (external constraints, population slightly fluctuates but mainly remains stable)
Define carrying capacity
Max. population that an environment can support
Limiting factors of population growth
Interspecific competition - between different species
Intraspecific competition - between same species
Abiotic factors - pH, water/oxygen availability, light, temperature
Biotic factors - disease, competition for food, predators
Immigration - into a particular area
Emigration- out of an area
Natural disasters affect density of a population
What are the effects of intraspecifc competition?
Stage 1 - resources are plentiful
Stage 2 - more individuals to share space and food. Resources become limited, population decreases
Stage 3 - less competition means more organisms survive and reproduce. Population begins to grow
Predator-prey relationships
Stage 1- increase in prey = more food for predators, predator population grows
Stage 2 - increased predators = decreases prey as they get eaten
Stage 3 - reduced prey = less food for predators so intraspecific competition for food begins
Stage 4 - predator population decline = less prey gets eaten so their population grows
Define conservation
Maintenance of biodiversity through active human management
Example of conservation
Forest Stewardship Council (FSC) manage forest so that they provide timber sustainably
What is the importance of conservation?
Economic - source of trade
Social - sightseeing, enriches lives
Ethical - moral responsibility to conserve for future generations
Define sustainable resource
A renewable resource that will not diminish or run out
Aims of sustainability
○ Preserve the environment
○ Ensure resources are available for future generations
○ Live comfortably
○ enable LEDC’s to develop
○ Create balance of consumption between MEDC’s and LEDC’s
Describe coppicing
Tree trunk is cut close to the ground and new shoots grown from cut area
What is the benefit of rotational coppicing?
It allows the newly coppiced area to grow
Maintains biodiversity and the trees can’t grow enough to block light
How do timber companies ensure sustainable production
○ Selective cutting
○ Replace trees through replanting
○ Manage pests and pathogens
○ Plant trees an optimal distance
○ Ensure areas of forest remain for indigenous people
Describe sustainable fishing
○ Fishing quotas
○ Nets with different mesh sizes
○ Allow commercial and recreational fishing at certain times only
Masai Mara
Semi- nomadic farming: allows vegetation to grow
Vegetation removed - increases risk of soil erosion
Ecotourism - jobs, improved infrastructure, can lead to soil erosion in hiking trails
Rhino horns - illegal poaching, park rangers and specialist equipment
Elephants trample on crops - fenced off areas
Legal hunting for over populated animals
