B6

• Land use negative impacts

  • More land being used for houses, farming, shops, roads, and factories, destroying habitats
• Pitfall traps


  1. Used to sample small insects like beetles or spiders

  2. Container buried in the ground with a piece of wood covering the top to allow insects to climb in

  3. Capture-recapture method is usually used

  4. Traps are checked regularly to ensure insects are not eaten

  5. Insects that fall into the trap are marked harmlessly and then a few days later the trap is set up again to estimate population size
• Pooters

  1. Small jar used to collect animals

  2. One tube goes over the insect and suction is applied through the other tube

  3. Mesh covering to prevent insects from being swallowed
• Pollution negative impacts

  • Sewage, fertiliser, and toxic chemicals polluting water
  • Smoke and acidic gases polluting air
  • Landfill and toxic chemicals polluting land, leading to death of plants and animals
• Hunting negative impacts

  • Many species becoming threatened
  • Disruption in food webs and environmental imbalances
• Nets


  1. Useful for collecting flying insects like butterflies

  2. Swept through long grass and counted

  3. Repeated over different areas to estimate population
• Positive impacts of human interactions with ecosystems


  • Preservation of habitats
• Negative impacts of human interactions with ecosystems

  • Land use
  • Hunting
  • Pollution
  • Deforestation
• Deforestation negative impacts


  • Cutting down trees for other land use purposes
  • Release of more CO2 into the environment contributing to global warming
  • Decrease in habitats and biodiversity
• Biodiversity


  The variety of different species of organisms on Earth or within an ecosystem. High biodiversity means the ecosystem will be stable, as species would be less dependent on each other for things such as food and shelter
• Quadrats

  1. Used to study ecology, estimate distribution and abundance of organisms within a large area by looking at smaller representative samples

  2. Placed along a transect to count the amount of each organism

  3. Can be randomly placed across the whole area

  4. Percentage cover can also be estimated but is subjective and less accurate than counting

  5. Accuracy can be improved by doing more samples, repeat testing, or completing sampling over larger transects
• Less trees means less CO​2​ is taken in

  The number of habitats are reduced, decreasing biodiversity
• Environmental changes affect the distribution of species in an ecosystem
• Plants produce CO​2​ as they respire


  Producing CO​2​ as they respire
• Reducing the rate of deforestation

  • Selective logging - trees only felled when they reach a certain height
  • Afforestation - replacing cut down trees
• An increasing human population means that it is becoming difficult to ensure that everyone is able to have food (food security)
• Selective breeding or artificial selection is when humans breed certain plants or animals which have desirable characteristics
• Breeding programmes

  • To stop endangered animals becoming extinct
• Sustainability is an issue because more of the population is becoming wealthy and so their diet changes to an increase in meat and fish consumption
• Global warming may lead to droughts which will make it more difficult to grow crops
• Recycling


  • Reduces the amount of land taken up for landfills
  • Reduces the rate at which natural resources are being used up
• Benefits

  • Conservation of species and habitats maintains biodiversity
  • Ecotourism brings in money to support conservation and educates people without disrupting their natural environment
  • Captive breeding programmes can prevent extinction
  • Nature reserves reduce hunting by removing tusks and horns of animals so poachers have nothing to hunt for
• New pests and pathogens are constantly entering but the genetic modification and selective breeding of certain crops and animals means increased vulnerability to new pathogens
• Challenges

  • It can be very expensive and difficult to monitor conservation schemes
  • It is difficult to get all countries to sign agreements, for example to stop overfishing, and so it may be difficult to have a large impact
  • Captive breeding programmes may mean that some species cannot be released back into the wild as they can't hunt efficiently
  • Removing tusks and horns can be seen as unethical
• Agricultural solutions

  • Hydroponics: growing crops in glasshouses by replacing soil with a mineral solution, allowing for careful control of growth by adjusting temperature etc.
  • Biological control: release a natural predator into the area where the crops are being grown
  • Gene technology: modifying crops or animals to have better yields, e.g., plants producing bigger fruits
  • Herbicides: used to get rid of competing plants so that the maximum amount of energy and mass is conserved
  • Insecticides and pesticides: gets rid of animals that eat the crops so that the maximum amount of energy and mass is conserved
• Environmental changes affecting distribution of organisms

  • Temperature: Climate change may lead to insects migrating to places in the world which are becoming hotter
  • Water availability: Populations will migrate to find water
  • Atmospheric gas composition: Certain pollutants can affect the distribution of organisms, e.g., lichen cannot grow in places where sulfur dioxide is present
• Trees take in CO​2​ when they photosynthesise


  Less trees means less CO​2​ is taken in
• Selective breeding


  Select individuals with desirable characteristics and breed together, Choose the best offspring and breed them together, Repeat process over many generations until all offspring have the desired characteristic
• Genetic modifications in crops


  Genetically modifying crops to contain nutrients in countries where it may be difficult to obtain these nutrients naturally
• Steps of genetic engineering

  Genes from chromosomes are 'cut out' using restriction enzymes leaving 'sticky ends, 2) A virus or bacterial plasmid is cut using the same restriction enzyme to create sticky ends, 3) The loop and gene sticky ends are joined together by DNA ligase enzymes, 4) The combined loop is placed in a vector, such as a bacterial cell, and allowed to multiply to contain the modified gene
• Perceived risks of genetic engineering

  • Effect on wild flowers and insects, Infertility in other species, Reduced biodiversity, Potential effects on human health, Genetic engineering in humans, Selection pressure leading to super weeds and pests
• Desirable characteristics in animals

  • Animals producing lots of meat, Chickens that lay large eggs
• Cropping


  Maximizing energy and mass conservation, reducing biodiversity, potential impact on birds, and unintentional health consequences
• Genetic engineering


  Modifying the genome of an organism by introducing desirable characteristics
• Desirable characteristics in plants

  • Disease resistance, Large flowers, Large fruits
• Perceived benefits of genetic engineering

  • Useful in medicine to mass produce certain hormones, Improve yields in agriculture, Produce crops with extra vitamins, Help solve world hunger
• Interaction between HPV and cervical cancer

  Viruses living in cells can trigger cancers, most cervical cancer cases are linked with the HPV virus
• Genetically modified crops help ensure that less people get deficiencies in nutrients in countries where a large variety of crops cannot be grown
• Interaction between HIV and TB

  HIV affects the strength of the immune system, making individuals more susceptible to TB
• Crops can be genetically modified to contain nutrients in countries where it may be difficult to obtain these nutrients naturally