Populations and Sustainability

• Draw, label, and annotate with explanations, a generalised growth curve for natural populations.

  Lag phase - Slow growth - small number of individuals initially present. Birth rate > Death rateLog phase - Rapid growth - number of breeding individuals increases, total population multiplies exponentially. No constraints act to limit population explosion. Birth rate >> Death rateStationary phase (Carrying capacity) - Stable state - Further population growth prevented by external constraints. Population size fluctuates but remains relatively stable. Birth rate = Death rate

  
• Define the terms "abiotic factor", "biotic factor", "limiting factor" and "carrying capacity".

  Abiotic factor - non-living conditions in a habitatBiotic factor - living components of an ecosystemLimiting factor - factor which limits the rate of a processCarrying capacity - the maximum population size that an environment can support
• Give 3 examples of limiting factors for population size and explain how each affects population size.

  Biotic: Predation, Food supply, Grazing, Parasitism, Disease, Intraspecific and Interspecific competitionAbiotic: Temperature, pH, Light intensity, Water availability, Oxygen concentration, Humidity
• Define the terms "density dependent factors" and "density independent factors" and give 3 examples of each.

  Density dependent factors - factors whose strength depends on the population size. Competition, Predation, Grazing, DiseaseDensity independent factors - factors that will affect the same percentage of the population regardless of its size. Natural disasters, Temperature
• Define the terms "migration", "immigration" and "emigration"

  Migration - the movement of individuals from one place to anotherImmigration - the movement of individuals into a particular areaEmigration - the movement of individuals out of a particular area
• Describe the terms "r-strategists" and "K-strategists", and describe the differences between them

  r-strategists:Short lifespan, Many offspring, Early onset of maturity, Small body size, Reproduce once during lifetime, No parental care, Unstable environmentK-strategists:Long lifespan, Few offspring, Late onset of maturity, Large body size, Reproduce more than once, Parental care is common, Stable environment
• Define the terms "intraspecific competition" and "interspecific competition"

  Intraspecific competition - competition between organisms of the same speciesInterspecific competition - competition between organisms of different species
• Give 4 examples of what organisms might compete for.

  Space, food, light, water
• Describe and explain the "competitive exclusion principle"

  Where 2 species are competing for limited resources the one that uses the resources more effectively will ultimately eliminate the other
• Explain why intraspecific competition is an example of a density dependent biotic factor, and why it may result in fluctuations in population size over time.

  When resource is plentiful in a habitat all organisms have enough to survive and reproduce. This results in an increase in pop. size. As a result of increased population, there are many more individuals that share food or available space. Resources now limited; not enough is available for all organisms to survive - pop. decreases.Less competition exists as smaller population means fewer organisms are competing for the same resources. This means more organisms survive and reproduce, resulting in population growth.
• Define the terms "predator", "prey", and "predation".

  Predation - the capturing of prey in order to sustain lifePredator - an animal that naturally preys on others - captures and feeds on other animals
• Describe and explain the general pattern shown in predator-prey relationships

  An increase in the prey population provides more food for the predators, allowing more to survive and reproduce, resulting in an increase in predator population. The increased predator population eats more prey organisms causing a decline in the prey population as its death rate is greater than the birth rate. Reduced prey population can no longer support the large predator population. Intraspecific competition for food increases resulting in a decrease in the size of the predator population. Reduced predator numbers result in less of the prey population being killed. More prey organisms survive and reproduce, increasing the prey population - cycle begins again.Rarely this simple in the wild - other factors such as availability of food for prey, presence of other predators and changes in abiotic factors (seasonal) also have an effect.
• Define the terms "conservation" and "preservation", and explain the difference between the two

  Conservation - the maintenance of biodiversity through human intervention or actionPreservation - protection of an area by restricting or banning human use - so that the ecosystem is kept exactly as it isDifference - conservation active, preservation passive
• Define the term "reclamation" and give 3 examples of conservation and 3 examples of preservation.

  Reclamation - Restoration of land/ecosystems that have been degraded by human activity or impaired by natural phenomenaConservation: Using grazing to keep Fen land from becoming woodland, Removal of invasive species such as Rhododendron, Legal hunting of animals in nature reserves to reduce the population from potentially damaging levelsPreservation: International agreement preventing large scale human activity in Antarctica, Only scientists are allowed on the island of Surtsey - a new island formed by volcanic activity off Iceland, Gating pristine caves to prevent people entering in order to protect the fragile ecosystems and geology
• Define the terms "ecological", "economic", and "aesthetic" when referring to reasons for maintaining biodiversity

  Ecological - reasons concerning the potential impact on other species and whole ecosystemsEconomic - reasons involving people, communities or companies earning a living or making more money from the biodiversity in a sustainable wayAesthetic - reasons based around the beauty of nature and its ability to enrich lives and inspire people
• Define the terms "social" and "ethical" when referring to reasons for conservation of biological resources and give two examples of each.

  Social - reasons that are for the benefit of society, providing areas for relaxation,exercise and hobbiesEthical - reasons based on the rights given to organisms (or the environment) by some people, or on the moral responsibility we have to future generations
• Define the term "sustainability" and "sustainable resource"

  Sustainability - the ability to continue a particular action indefinitely without using resources in a way that could eventually make them run out and without leading to irreversible damage to the environmentSustainable resource - a resource that can be exploited economically in a way in which it will not diminish or run out
• Describe 5 aims of sustainability.

  Preserve the environmentEnsure resources are available for future generationsAllow humans in all societies to live comfortablyEnable less economically developed countries to develop through exploiting their natural resourcesCreate more balance in the consumption of these resources between LEDCs and MEDCs
• Describe 3 things that can be done to reduce the demand for a resource and therefore make it easier to manage sustainably.

  Reduce, Reuse, RecycleReduce consumption of resourceReuse resource in original formRecycle resource after use to create new things
• State two methods of small scale timber production.

  Coppicing and Pollarding
• Define the terms "coppicing", "pollarding" and "rotational coppicing".

  Coppicing - cutting a tree trunk back close to ground level to allow new shoots to grow up from this stump, and then harvesting the shoots at regular intervalsPollarding - cutting a tree trunk back to a few metres above ground level to allow new shoots to grow up from the top of this trunk, and then harvesting these shoots at regular intervalsRotational coppicing - dividing woodland up into sections, trees are only coppiced in one section each year. There are enough sections so that the first section has fully regrown by the time all other sections have been coppiced.
• Describe the process of coppicing and explain the advantage of rotational coppicing

  Cutting a tree trunk back close to ground level to allow new shoots to grow up from this stump, and then harvesting the shoots at regular intervals.Rotational coppicing allows time for growth between cutting so maintains habitats for other organisms in between cutting of areas.
• Explain an advantage of pollarding over coppicing.

  As new growth is higher up, it is protected from grazers such as deer. The trunks also provide a habitat that is absent in coppiced trees.
• Describe the difference between harvesting in large scale timber production and harvesting in small scale timber production.

  Trees are replaced by replanting rather than natural regeneration.
• Describe 5 practices that can help large scale timber production to be sustainable.

  Practise selective cuttingReplace trees through replantingPlant trees optimal distance apart to reduce competition - maximises yieldManage pests and pathogens to maximise quality and size of yieldEnsure areas of forest remain for indigenous people
• Describe the disadvantages of large scale timber production.

  Habitats are destroyed, minerals in the soil are depleted and the bare soil that is left is vulnerable to erosion.
• Name and describe an international agreement that aims to ensure fishing is sustainable in the EU.

  Common Fisheries Policy (in the EU)Sets fishing quotas and regulations
• Describe 3 methods which can help fishing to be sustainable.

  Larger mesh in nets/new net designs - allows younger individuals to escape so they can mature fully and reproduce, reducing by-catch.Restrictions on time of year for fishing certain species to protect the breeding season allowing the number of individuals to increase.Fish farming - reduces pressure on wild populations while maintaining protein supply for diets.
• Explain why overfishing in one particular area is not likely to make a species extinct.

  It will reduce or eliminate the population in the specific area (locally extinct) but the species will survive elsewhere
• State what MMNR stands for and where it is.

  Masai Mara National ReserveSouth Kenya
• Describe the ecosystem of the Masai Mara.

  SavannahFertile, rich grassland and woodland around river. Open plains with scattered shrubs and trees away from the river.
• Describe the impact local human populations have had on the ecosystem of the Masia Mara.

  Used to practice semi - nomadic farming but now larger populations set up on edges of Masai Mara. More cultivation of crops and trees removed for fuel as well as cultivated grazing. Removal of soil nutrients - heavy reliance on fertilisers as grassland is turned to cropland. Risks of soil erosion increased.
• Define the term "ecotourism", explain its value to the Masia Mara and state 3 principles of ecotourism.

  Tourism directed towards natural environments to support conservation efforts and observe wildlife.Ensure that tourism does not exploit the natural environment or local communitiesConsult and engage with local communities on new developmentsEnsure that infrastructure improvements benefit local people as well as visitors
• Describe the negative impacts of ecotourism.

  Tourist movements such as hiking trails and vehicles contribute to soil erosion and habitat changes.
• Describe the change in population size of the black rhino since the early 1970s and describe the threats to the black rhino and what conservation efforts were put in place.

  In 1972 there were 100+ black rhino by 1982 only a handful. Numbers are now increasing but have not yet recovered to the levels of the 1970s.Rhino horn used in traditional medicine in south east Asia.Employment of rangers with comms, vehicles and other infrastructure and equipment has acted as a deterrent to poachers.
• Describe 4 scientific research projects that have been undertaken in the Masai Mara.

  Michigan State university - Behaviour and physiology of the predator the spotted hyenaSubalusky and Dutton - Flow assessment of Mara river basinThe Mara Predator Project - Catalogues and monitors lion populations to identify responses to change The Mara Meru cheetah project - Montito cheeah population and evaluate human impact
• Describe 4 ways in which there is a conflict between human needs and conservation/preservation in the Masai Mara and suggest how this conflict can be balanced.

  Elephants trample crops and damage homesteads. Land can be fenced but this disrupts natural migration patterns.There is legal hunting to maintain the levels of some populations and the numbers are constantly monitored to maintain balance.Wilderbeest outcompete cattle for grass and vice versa, there are also diseases introduced between the domestic and wild populationsThe increasing human population needs more homes and farmlands but this decreases wildlife density.
• Describe the location of the Terai region of Nepal.

  Southern part of Nepal, along the border with India
• Describe the ecosystem of the Terai region of Nepal.

  Hot and humid in summer. Fertile soil. Well-watered flood plains and tropical and subtropical forest. Extreme biodiversity.
• Describe the impact local human populations have had on the ecosystem of the Terai region.

  Large areas of forest cleared for agriculture and selling timber increasing the effects of monsoon flooding.