4.2.1 - Biodiversity (set B - Factors Affecting Biodiversity + Maintaing) Flashcards
Explain the factors that affect genetic biodiversity?
- mutations in the DNA of an organism - creates new alleles
- interbreeding between different populations - eg when an individual migrates from one population and breeds with a member of another - alleles are transferred (gene flow)
- genetic biodiversity decreases through selective breeding
Explain how genetic biodiversity can decrease within a population - give 2 ways and explain them?
- selective breeding - only a few individuals within a population are selected for their advantageous characteristics, and are bred - eg breeding of pedigree animals and crops
- captive breeding programs - in conservation centres/zoos where only a small number of captive individuals of a species are available for breeding
Explain how natural selection and the founder effect impact genetic biodiversity?
Natural selection - species will evolve to contain primarily the alleles which code for advantageous characteristics - over time alleles which are less helpful will be lost from a population
- founder effect - where a small number of individuals create a new colony (geographically isolated from the original) - gene pool of the new population is small
Give 6 factors which affect genetic biodiversity?
- selective breeding
- captive breeding programmes
- rare breeds
- natural selection
- genetic bottlenecks - where few individuals with tin population survive an event, thus reducing the gene pool as only alleles of survivors passed on
- the founder effect
Outline the 3 main human factors affecting biodiversity?
Deforestation - permanent removal of large areas of forest for wood and to create space for infrastructure
Agriculture - increasing amount of land converted to farming (generally for single crops - monoculture)
Climate change - increasing global temperatures
Outline 3 ways deforestation reduces biodiversity?
- directly reduces number of trees within an area - if only a specific tree is felled, the species diversity is reduced
- reduces number of animal species present in an area - destroys their habitats (source of food and home) which disrupts the food web
- forces animals to migrate to other areas - impacting biodiversity of these regions
Explain how agriculture impacts biodiversity - give 4?
- removal of hedgerows - to allow use of large machinery, and free up extra land for crop growing (reduces number of plant species present in an area by destroying their habitat)
- use of chemicals (pesticides and herbicides) - reduces species diversity by directly destroying the pests or indirectly destroying the food source of other organisms
- Herbicides kill weeds which reduces plant diversity and animal diversity by removing an important food source
- monoculture
Explain how monoculture impacts biodiversity?
Many farms specialise in production of one crop, this lowers biodiversity as only one species of plant is present which wont support many animal species
- growth of oil palm plantations is a leading cause of deforestation in rainforests
Outline 3 key findings from the intergovernmental panel on climate change (IPCC)?
- average artic temp has increased at almost twice the global average rate in the past 100 years
- mountain glaciers and snow cover have declined on average in both hemispheres
- global average sea level rose by an average of 1.8mm per year from 1961
Explain how climate change impacts biodiversity - give 3?
- melting of polar ice caps could lead to extinction of few plants and animal species living in these regions
- rising sea levels could lead to loss of habitats
- higher temps and less rainfall would lead to some plant species dying - xerophytes becoming more dominant
Outline 3 aesthetic reasons for maintaining biodiversity?
- presence of different plants and animials in our enviornment enriches our life’s
- natural world provides inspiration for people
- studies show patients recover more rapidly from stress and injury when they are supported by plants and a natural environment
Outline 4 economic reasons for maintaining biodiversity?
- soil erosion and desertification due to deforestation can impacts a country’s ability to grow crops
- non-sustainable removal of raw materials will lead to a collapse of industry in an area once all the resources are exploited
- large scale habitat and biodiversity loss means species with potential economic importance are lost before they are discovered (loss of potential medicines)
- high biodiversity areas provided a pleasing and attractive environment which encourages tourism
explain a problem with continuous monoculture - focus on soil depletion?
Leads to soil depletion (reduction in diversity of soil nutrients) due to same crop taking in the same nutrients year after year and then being harvested before nutrients can be recycled
- makes ecosystem more fragile - the crops it can support will be weaker and more easily affected by insects, plant competitors and microorganisms
Outline 2 ecological reasons for maintaining biodiversity?
- all organisms are interdependent for survival - removal of one species may significantly impact others - eg plants rely on bees for pollination
- some species play key role in maintaining structure of an ecological community (keystone species) - they have larger effect on enviornment relative to their abundance - when they are removed the habitat is drastically changed, all other species are affected
Define conservation?
Preservation and careful management of the environment and of natural resources by conserving the natural habitat in an area, organisms chances of survival are maintained
- two way in situ conservation and ex situ conservation
