24 - Population and Sustainability Flashcards
What are 4 examples of environmentally sensitive ecosystems?
- Antarctica 2. Snowdonia 3. Lake District 4. Galapagos Islands
What is a population?
All the organisms of one species in a habitat
What is interspecific competition?
Competition for resources between different species
What is intraspecific competition?
Competition for resources between members of the same species
What pattern can intraspecific competition follow and what does this mean?
Can be cyclic, so greater resources mean a larger population
What 2 things can interspecific competition affect?
- Distribution 2. Population of both species (both will usually decrease)
What is carrying capacity?
The maximum stable population size of a species that an ecosystem can support
What is population density?
Number of individuals per unit area of a chosen habitat
What are the 4 most basic factors which affect population density?
- Birth rate 2. Death rate 3. Immigration rate to habitat 4. Emigration rate from habitat
What 2 types of factors can affect population size?
- Density dependent 2. Density independent
What are 3 examples of density dependent factors which affect population size?
- Predation 2. Disease 3. Competition
What are 2 examples of density independent factors which affect population size?
Climate or catastrophe
What type of feedback are predation cycles an example of?
Negative feedback
What are the 5 phases of a population growth curve?
- Lag phase 2. Log phase 3. Stationary phase 4. Stable phase 5. Death phase
What happens during the lag phase of a population growth curve?
Population growth begins slowly from a few individuals
What happens during the log phase of a population growth curve?
Exponential growth in ideal conditions
During what phase of a population growth curve is maximum growth rate reached?
Log phase
What happens during the stationary phase of a population growth curve?
Growth rate begins to slow as factors become limiting
What happens during the stable phase of a population growth curve?
Population stable
During what stage of a population growth curve is carrying capacity reached?
Stable phase
What normally prevents populations from undergoing uncontrolled exponential growth?
Limiting factors
What happens during the death phase of a population growth curve?
The population crashes and the process of the curve restarts
What causes the death phase of a population growth curve?
A sudden change in the environment which lowers carrying capacity
What is a limiting factor?
An environmental resource or constraint which limits population growth
What is the competitive exclusion principle?
No two species can occupy the same niche in the same habitat at the same time, so the species which uses resources more efficiently will ultimately eliminate the other
What happens when two species are competing for the same food source but one is better adapted than the other?
The less well adapted one is outcompeted
What is predation?
An interaction in which one organism kills another for food
What are the 3 stages of the effects of intraspecific competition on population size?
- When a resource is plentiful in a habitat, all organisms have enough to survive and reproduce, causing a rise in population size 2. Increased population means more organisms have to share available resources. As resources are now limited, the population decreases in size 3. Less competition exists due to smaller population, so growth occurs again
What type of competition is almost all predation?
Interspecific
What can happen if a predator or prey species does not evolve?
They could go extinct
Do all predator-prey relationships show the same pattern?
In general yes
What are the stages of a predator-prey relationship?
- Increase in prey population causes more food for predators, so predator population rises 2. Increased predator population eats more prey, so prey population decreases 3. Reduced prey population can no longer support predator population, so it falls 4. Reduced predator population causes prey population to increase as less are killed
Why are predator-prey relationships rarely as simple as the model?
There are other biotic and abiotic factors to consider
What is conservation?
The protection and management of an ecosystem so that natural resources can be used before running out
What is preservation?
The protection of ecosystems so that they are kept exactly as they are
What type of process is conservation and why?
A dynamic one, as it needs constant adaptation to changes within the ecosystem
What is reclamation?
Restoring ecosystems which have been damaged or destroyed
What is preservation commonly used to preserve?
Sensitive resources and species
What are 3 examples of commonly preserved ecosystems?
- Marine conservation zones 2. Nature reserves 3. Newly discovered caves
What 2 things are maintained in conservation?
Habitats and genetic diversity within a species
What are 4 classes of reasons for the importance of maintaining biodiversity?
- Economic 2. Ecological 3. Ethical 4. Social
What are 5 techniques used as part of conservation?
- Managing land 2. Taking steps to encourage new habitats 3. Removing animals to captivity 4. Growing plants in cultivation 5. Reclamation
What is a technique humans can use to encourage new habitats?
Controlled habitats
Is anything removed from a preserved area?
No
What are 3 threats to biodiversity?
- Habitat loss 2. Introduced species 3. Overexploitation
What are 3 reasons wild populations may be overexploited by humans?
- For food 2. For sport 3. For commerce
What are 3 reasons habitats may be disrupted by humans?
- Intensive agricultural practices 2. Increased pollution 3. Building
What is a sustainable resource?
Renewable resource that is being economically exploited in such a way that it will not diminish or run out.
What are 5 methods used for conservation?
- National parks 2. Green belts (areas of green land) 3. SSSIs (Sites of Special Scientific Interest) 4. Legal protection 5. Ex Situ conservation
What is sustainable management of the environment necessary for?
Conservation of natural resources for future generations
What are the 5 aims of sustainability?
- Preserve the environment 2. Ensure resources are available for future generations 3. Allow humans in all societies to live comfortably 4. Enable LEDCs to develop through exploiting their natural resources 5. Create even balance in consumption of resources between LEDCs (less economically developed countries) and MEDCs (more economically developed countries)