B6: Global challenges Flashcards
what does sampling mean
- to take observations/measurements from a small area, which is representative of a larger area
what are the different ways you can sample animals
- pooters: suck on mouthpiece to draw insect into holding chamber - filter stops organism entering mouth
- sweep nets: sweep large net in air/grass to catch insects
- kick sampling: ‘kick’ a river bank to disturb mud + vegetation - hold a net downstream to catch organisms bein released into flowing water
- tree beating: put large white cloth under tree/bush - shake/beat it and organisms will fall into cloth
- pitfall traps: dig hole in ground to which insects/invertebrates will fall into - cover with roof so water doesn’t fill the hole
how do you identify unknown organisms
- using identification keys to identify living organisms
what do identification keys do
- ask a series of questions about an organism’s characteristics to identify it
what are the 2 main types of identification keys
- branched key (spider key) - by answering yes / no for each question you can determine an organism’s identity
- numbered key (or dichotomous key) - the correct answer to a question tells you what question to answer next - eventually after answering a series of questions you’ll identify your organism
what tool can you use to sample plants + how
- a quadrat (square frame divided into a grid)
- place it on the ground to take a sample + record the type and number of organisms within each section
- to figure out population, multiply the mean by the total area
- mean = population / area
what is the equation for estimated population size
estimated population size =
1st sample size x 2nd sample size
____________________________________________
number of recaptured marked individuals
how are animal populations estimated
- using the capture-recapture technique which scales up results from a small sample area to estimate population
describe how to use the capture-recapture technique to estimate animal population
- capture organisms from a sample area
- mark individual organisms, then release back into community
- at later date, recapture organisms in the original sample area
- record the number of marked + unmarked individuals
- estimate the population size using the equation
what are the 2 ways plants can be sampled
- random sampling
- non random sampling
what is random sampling
- when you randomly sample areas of plant populations
- mark out a grid on the sample area + use random number generator to determine the coordinates of where to place your quadrat
> prevents bias (normally tempting to place quadrat in areas that look interesting)
what is non random sampling
- samples are taken along a line to study how the distribution of organisms varies over a distance
> known as a transect - samples can be taken by counting organisms that touch the line, or by placing quadrat at fixed positions along the line
what is biodiversity
- the variety + variability of life on Earth
why is biodiversity important
- species are interconnected, so the removal of one species can affect others
> could lead to a loss of another species’ food/shelter - biodiversity is essential for maintaining a balanced ecosystem
what do humans rely on biodiversity for
- raw materials
> food, wood + oxygen - however humans are the leading cause of loss of biodiversity
how is biodiversity lost
- now over 7 billion ppl on earth which caused increased need for food + materials which is reducing biodiversity through:
> deforestation
> agriculture
> hunting + overfishing
> pollution
what is the leading cause of loss of biodiversity
- humans
how does deforestation contribute towards the loss of biodiversity
- deforestation reduces number of trees + supported animal species, as their food source / habitat has been lost
> can affect predator species
why has agriculture increased
- due to higher demands for food for the growing population
- more land is farmed
how does intensive farming lead to the loss of biodiversity (agriculture)
- removing hedgerows to use large machinery + freeing up extra land for crops
> reduces number of plant species + destroys animal habitats e.g. mice, hedgehogs - using pesticides to kill pests which eat crops / live on livestock
> reduces number of pest species + removes food source of other organisms - pesticides can accumulate in food chain, killing animals that weren’t targeted - using herbicides to kill plants growing where they aren’t wanted
> reduces plant species + animals species present e.g. removing source of food/shelter
what is deforestation + why is it done
- deforestation is the permanent removal of large areas of forest
- removing forests:
> provides wood for building
> creates space for roads, buildings, and agriculture
how does hunting + overfishing lead to a loss of biodiversity
- overfishing has led to some fish populations decreasing significantly / even being lost from some areas
> other marine species may also be caught + killed - hunting decreases the target species’ population, which removes food for other species
> this can further reduce biodiversity as the food chain is disturbed
what methods are used to increase biodiversity
- conservation
- captive breeding
- seed banks
how have humans increased pollution levels
- the expansion of the human population has resulted in burning of more fossil fuels, increased use of fertilisers and herbicides
> this has led to increased pollution levels
how does pollution lead to a loss of biodiversity
- when pollutants enter the environment, they have an impact on the number + types of organism
> the more populated an area, the fewer the number of species that can survive - gases are also produced from burning of fossil fuels: CO2, methane, nitrous oxide, sulfur dioxide
> sulfur dioxide causes acid rain, which results in the death of trees and fish
what does conservation mean + how does it help
- conservation means protecting a natural environment to ensure habitats aren’t lost
> protecting an organism’s habitat increases their chance of survival, allowing them to reproduce
how can nature reserves + natural parks be actively managed to protect the habitat
- controlled grazing: only allowing animals to graze land for certain period of time, giving plant species time to recover
- restricting human access: e.g. providing paths to prevent plants from being trampled
- feeding animals: to ensure more organisms survive to reproduce
- reintroduction of species: adding new individuals of a species into an area with lower numbers, or where the species has not survived
what are some conservation methods
- protected habitats for species to live in
- legal protection to stop hunting + trade
- artificial ecosystems to replace destroyed ones
- seed banks to store the seeds from rare plants
- education to make people aware of the problem
- captive breeding in zoos to increase the population
what is captive breeding
- breeding animals in human-controlled environments such as zoos/aquariums
- animals given shelter, plenty nutritious food, veterinary treatment + predator-free environment
- selective breeding partners can be imported from other zoos
what do scientists working on captive breeding programmes aim to do
- create a stable, healthy population of a species
- gradually reintroduce the species back into its natural habitat
what are some problems associated with captive breeding
- maintaining genetic diversity can be difficult since few breeding partners are available
- organisms born in captivity may not be suitable for release into the wild
> e.g. predators bred in captivity may not know how to hunt for food
how can you prevent extinction of species
- as ew species are evolving, others are becoming extinct
- using seedbanks as a store of biodiversity
- seeds are carefully stored so that new plants may be grown in the future
what are seedbanks + how do they help increase biodiversity
- seed banks are a way of conserving plants
- seeds are carefully stored so new plants may be grown in the future
- a seed bank is an example of a gene bank - a store of genetic material
what are conservation agreements
- to conserve biodiversity, local + international cooperation is required to preserve habitats + individual species
- many animals naturally move between countries, so global action is required
what are the 2 different types of conservation agreements
- international agreements
- local agreements
what is the Rio Conventions
- the Rio Earth Summit of 1992 resulted in an international agreement known as the ‘Rio Conventions’
> these require countries to develop strategies for sustainable development, to reduce greenhouse emissions + combat desertification - altogether, the conventions aim to maintain biodiversity - however, individual countries can’t be forced to implement them
how do intergovernmental organisations (e.g. IUCN - international union for the conservation of nature) help to secure agreements between nations
- IUCN publishes the ‘Red list’, detailing the current conservation status of threatened animals
- the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) treaty regulates the international trade of wild plants + animals + their products, to prevent over exploitation
> this treaty protects more than 35,000 species
what are local agreements
- through Stewardship Scheme, farmers in England are offered government payments to conserve the landscape
- their aim is to make conservation a part of normal farming practices
> thus securing the beauty of the landscape + biodiversity found there
how is tourism linked to a loss of biodiversity
- large numbers of human visitors in any region can lead to habitats being lost / destroyed, leading to loss of biodiversity
how can tourism be beneficial to increasing biodiversity
- tourism brings money that can be used to support natural wildlife by extending + improving habitats + preventing poaching
- landowners are encouraged to maintain biodiversity, if this decreases, tourists won’t come
how does ecotourism ensure that tourism doesn’t have a negative impact on natural environments / local communities
- supports conservation, whilst allowing people to observe wildlife
- tourists often restricted to certain areas + asked to keep on footpaths
> ensures animal breeding grounds aren’t disturbed or endangered plants trampled
what does Ecotourism aim to ensure
- that tourism doesn’t have a negative impact on the natural environment or local communities
how can ecotourism still have negative impact on the ecosystem
- evidence that tourist movements such as repeated use of hiking trails, or vehicles carrying tourists, may contribute to soil erosion + other habitat changes
how do scientists monitor pollution
- by regularly taking samples of plants + animals from environment to monitor the type + number of organisms present
- a decrease in range/number of species indicates that environmental changes have taken place
> the more polluted an area, the fewer the species present
what are indicator species
- organisms that can be used to measure environmental quality
> their presence (or absence) tells biologists that an area is polluted
what is one the most common forms of air pollution + what can it cause
- sulfur dioxide
- released from combustion of some fossil fuels
- causes acid rain, which can result in the death of trees + fish
what is water pollution caused by
- the discharge of harmful substances into rivers, lakes and seas
what indicator species are used to measure air pollution (sulfur dioxide)
- lichens
> have no root systems - most of their nutrition comes from air
> rainwater contains just enough nutrients to keep them alive
> air pollutants dissolved in rainwater, especially sulfur dioxide, can damage lichens + prevent their growth
what does a lack of lichens indicate
- high pollution
> as they die because of air pollutants dissolved in rainwater
how can you identify high levels of water pollution
- the higher the level of pollution, the lower the level of dissolved oxygen
what species of lichen are found in industrial / rural places
- species of lichens that can cope with high levels of pollution are found in industrial places
- species of lichens that can only grow in clean air are found away from towns
how can you estimate the oxygen content of water
- by identifying the indicator species found living in it, as some require higher oxygen content than others
what is food security
- the state of having reliable access to sufficient quantity of affordable + nutritious food
what factors have a positive impact on food security + explain
- inc amount of land available for growing crops: more crops can grow to feed larger population
- decreasing human population: less pressure to grow lots of crops, more food to go around
- inc CO2 levels: crops can photosynthesis, increasing crop yield
what is intensive farming
- the production of high-yield crops + animal products using the minimum amount of space
what factors have a negative impact on food security + explain
- changing diet in wealthier countries: people will eat more meat, but meat is more energy intensive to produce than plants
- global warming: more droughts, inc sea levels, less land for agriculture
- new pests + pathogens: lower crop yield
- inc agricultural costs: food more expensive, many can’t afford
what are some advantages of intensive farming
- high yields: maximum production achieved per unit of land, pesticides means less food lost to pests
- efficient energy conversion: movement restricted, minimising wasteful energy loss
- low cost of production
- less space needed: more space for natural habitat
- predators excluded: no energy loss to other organisms in the food web
how can intensive farming be achieved
- using fertilisers + pesticides yo aid plant growth
- maximising animals growth rates
- minimising labour inputs by using machinery
how can food production be increased
- maximising photosynthesis using industrial greenhouses
- using artificial fertilisers to aid growth
- using herbicides, insecticides, fungicides - removes competition
- using genetically modified crops
what are some disadvantages of intensive farming
- battery rearing of animals: less humane + cause disease to spread quickly through animal population
- fertilisers + pesticides: can damage environment + too much can wash into streams + lead to pollution - leads to eutrophication
- lower quality of food
do people agree with intensive farming
- many believe it to be wrong + that the disadvantages outweigh the advantages
what is sustainable food production
- the production of food that can be continued indefinitely
what is the alternative to intensive farming
- organic farming
> uses more natural methods to produce crops + rearing animals (avoids artificial fertilisers + pesticides )
> so reduces harm to environment
> yields are smaller, but products are more expensive
what are some examples of sustainable food production
- fish farming
- hydroponics
- biological control
- crop rotation
describe how hydroponics is a practice of sustainable food production
- plants are grown in water containing dissolved minerals (not soil)
> more plants can be grown in the same space - very sustainable
- advantages: plant grows quickly as they receive minerals needed, greater yield per area of land, pests can be controlled easily
- disadvantages: cost to set up
describe how fish farming is a practice of sustainable food production
- fish are bred + reared in large cages in seas/rivers
> protects fish from predators + makes them easier to catch - very sustainable
- advantages: allows wild population to recover, easy to catch, cheaper, can be fed ideal diet to maximise yield
- disadvantages: disease can spread quicky
describe how biological control is a practice of sustainable food production
- natural predators that kill pests are introduced; bred in large numbers + released
> removes competition from pests - very sustainable but needs repeating
- advantages: reduces pest population + no chemicals required
- disadvantages: needs repeating
describe how fertilisers are a practice of sustainable food production
- chemicals high in minerals (N,P,K) are spread over soil
> inc plant growth + flower and fruit production - not very sustainable, chemicals need to be produced
- advantages: inc yield of crop
- disadvantages: pollutes environment, eutrophication
describe how pesticides are a practice of sustainable food production
- toxic chemicals that kill pests are sprayed on land + animals can be dipped
> removes competition from pests, stops animal disease - not very sustainable, requires chemical production
- advantages: kills pests + removes competition
- disadvantages: can damage other organisms, bioaccumulation
what is selective breeding
- humans choosing the parents to breed together in the hope the offspring will have the desired characteristics
> aka artificial selection
describe the steps in selective breeding
- desirable feature (trait) is chosen
- organisms showing high levels of this feature are chosen + bred to produce offspring
- best offspring are chosen + bred again
- repeat for many generations
what are the uses of selective breeding
economic
- high yield: less animals + space, more income
- disease / insect resistant crops
- drought resistance crops
- fast growth
non economic
- pedigree dog breeding
what are the disadvantages of selective breeding
- reduces the gene pool (number of diff alleles)
> reduces variation
> more prone to disease / mutations
what are problems of selective breeding
- takes a long time (many generations)
- desired trait doesn’t always appear as expected
how have scientists eliminated the problems in selective breeding
- by using genetic engineering
how is genetic engineering better than selective breeding
- quicker - happens in 1 generation
- more predictable (accurate) as single genes are targeted
what does genetic engineering involve
- taking a gene from one species + putting it into another species
- it modifies the genome of an organism to introduce a desirable characteristic - genetic modification
- organisms produced by genetic engineering are called genetically modified (GM) organisms
> the organism produced is called a transgenic organism
why do scientists genetically engineer bacteria
- to produce useful substances such as hormones, vaccines & antibiotics
what is genetic engineering
- the process of modifying an organism’s genome to introduce desirable characteristics
what are some modern uses of genetic engineering
- finding out where genes are expressed in the body
- manufacturing useful substances
- producing crops resistant to bacteria
- producing crops with a greater yield
describe the steps in genetic engineering
- identify the characteristic you want and use a restriction enzyme which cuts out the gene from the DNA at specific base sequences
> this makes a staggered cut exposing unpaired bases on the ends of DNA strands called sticky ends - use the same restriction enzyme to cut open the bacterial plasmid (because it creates sticky ends that are complementary to each other)
- the gene is attached to the plasmid with a ligase enzyme which joins the sticky ends of the 2 DNA strands
- the plasmid vectors now containing the DNA are inserted into other cells (host cells) which can use the gene you inserted to produce the desirable characteristic
> to identify which host cells have successfully received the desired gene, antibiotic resistance markers are used
how can antibiotic resistance markers be used to identify the successful host cells
- insert a gene for antibiotic resistance (resistance marker gene) into the plasmid at the same time as inserting the gene coding for the desirable trait
- transfer the bacteria to an agar plate with the antibiotic + allow bacteria to grow
- bacteria colonies which grow must contain the antibiotic resistance marker gene + so therefore it will also contain the desired gene
what is a transgenic organism
- an organism that contains DNA from a donor organism (‘foreign DNA)
what is biotechnology
- the use of biological processes / living organisms to make products
what are GM organisms
- genetically engineered plants / animals that have been made to produce a useful characteristic
what are some examples of biotechnology
- making alcohol (use bacteria)
- making cheese / yogurt (use bacteria)
- antibody production (use GM bacteria)
- hormone production
- genetically modified (GM) crops
how do you produce a genetically modified organism (GM)
- very similar to the process used to genetic engineer bacteria
> but has an extra step, during which the engineered bacterium or virus carries the modified gene into a plant or animal cell
> plasmids, bacteria, and viruses can all be used as vectors to transfer foreign DNA into an organism
what are the pros of GM organisms
- inc yield
- resistance to disease + pests
- produces essential nutrients
- longer shelf life
- better flavour
what are some cons of GM organisms
- some believe the process to be unethical + should be banned
- concerns about the effects of GM crops on wild flowers, insects + whether eating GM crops may harm human health
