Population and Sustinability Flashcards
Describe the difference between population and community
Population - group of organisms of the same species living in an area/habitat
Community - population of organisms of all the different species in an area/ecosystem
Explain the importance of a niche to the survival of a species
Niche - role of an organism within its habitat. E.g where it eats
Survival of species is dependent to its niche
2 species can never occupy the same niche indefinitely due to competitive exclusion principle
Define ecology
The study of the inter relationship between organisms and their environment including abiotic, non living and biotic,living factors
Explain why grassland can be considered an ecosystem
It is an area in which there is interaction between biotic factors and abiotic factors. Biotic factors include the plant making up the grassland and the animals that graze or hunt in the grasslands.
Abiotic factors include- climate of area, light intensity and water availability
Define the term biomass and why biomass is measured in dry mass rather than wet mass
BM- total mass of living material in a specific area at a given time
Dry mass more accurate because water content varies in fresh biomass, measuring wet mass given an inaccurate energy store value
State the role and explain the function of plant within food chain
Plant are producers, convert energy from sunlight into chemical energy through the formation of photosynthetic products
What is biomass and how is it transferred? How can we measure this
Total weight of living matter in a certain area, transferred up tropic levels through consumption.
Can be measured in terms of mass,carbon or dry mass tissue
Give the formula for efficiency of biomass transfer
Efficiency - biomass transferred/biomass intake
How can human activities affect biomass transfer
Light, water,temperature maximised
Increased nutrients in soil
Pests and weeds removed
Growth rate boosted
Outline the roles of miceoganims in the nitrogen cycle
Nitrogen fixing bacteria e.g Rhizobium converts gaseous nitrogen into ammonia
Nitrifying bacteria convert ammonium compound into nitrites
Outline the role of organisms in the carbon cycle
Respiration of plants and animals add carbon dioxide into the atmosphere
Photosynthesis of plants remove carbon dioxide from the atmosphere
Decomposers decay plant and animal material in CO2
What is meant by primary succession
Where an area previously lacking of life is colonised by a community of organism
Summaries the process of primary succession
Pioneer species, able to survive harsh conditions, colonise the area
They die, decompose and add nutrients to the ground
Over time, allows more complex organisms to survive
What is the climax community and how is it reached
Final stage of succession, ecosystem is balanced and stacked.
Reached when the soil is rich enough to support large tress or shrubs
Define deflected succession
Where succession is interrupted, usually human interference
What is sampling
Selecting a group of individuals that will represent the whole target population
Measure the distribution and abundance of organism
Give methods of sampling and explain
Quadrats- used in small areas, randomly or regularly placed. Frequency or % covers calculated
Transects - larger areas. Sample taken along a line that crosses the habitat . Can be combined with quadrats in the form of a belt transects
Define carrying capacity
The maximum population size that a habitat can support, defined by presence of limiting factors
Give factors that limit the maximum size of population
Food, wafer, light, o2, parasites, predators
Describe the pattern of a typical predator - prey relationship in terms of population change
Prey is eaten by predator, resulting in predator population increasing and prey population decreasing
Fewer prey means increased competition for food, so predator population decreases
Fewer predators - more prey survives
What is meant by intra specfic and inter specific competion
Intra- competition between organisms of the same species
Inter - competition between organisms of different species
Differentiate between conservation and preservation
Conservation - maintains biodiversity of a habitat by allowing sustainable use of the resources there
Preservation- maintains biodiversity of a habitat by minimising human impact
Give reasons why we conserve and preserve habitats
Economic - food source, natural pest control, boost tourism
Social - many organisms can be used in medicine, aesthetics
Ethical - we have responsibility to maintain habitats for future generation
Define sustainability
Using resources in a way that also maintains them for future generations
What methods allow sustainable use of an ecosystem resources
Timber production - coppicing to encourage growth, replacing felled trees, selective cutting
Fishing - stocks not depleted, no overfishing, can continue indefinitely
Give an example of how the conflict between conservation and human needs can be balanced
Terai region
Over exploited for use in fuel.
Locals now have a responsibility to look after the forest
Give example of how human effects are controlled in sensitive ecosystem
Galápagos Islands
Many species and endangered due to hunting and tourism
New species introduced, but caused damage to native species
