Topic 1.6 Human Impact on Earth Flashcards
Human influence on Earth has led to the alteration of ecosystems. Huge destruction of habitats due to pollution, deforestation, agriculture, urban development and mining. A biodiversity crisis is occuring as species are deprived of certain biotic and abiotic features they require. Thus, they’re reproducing LESS causing their numbers to decline…eventually, this can lead to extinction!
a) What is the normal ‘background’ extinction rate? What does this value mean?
c) What does EX and EW mean
d) What does CR, EN, VU, NT and LC mean
e) What does DD mean? Why are some species graded DD?
a) Extinction is a natual process and normal ‘backgroud’ extinction rate is 10^-6 per year (i.e. every year, 1 specie in a million shall become extinct). Human activity in tropical areas has risen between 1000-10,000 times alone.
b) The IUCN - the international union for conservation of nature make assessments of plants and animals and GRADE them in accordance to their vunerability to extinction.
c)
EX = Extinct
EW = Extinct in the WILD
Threatened Species are graded by the following 2 LETTERS:
-CR = Critically Endangered
-En = Endangered
-VU = Vunerable
-NT = Near Threatened
-LC = Least Concern
d) Some are labelled as DD (i.e. data deficient, there isn’t enough data around them to be able to grade them)
Why can species be threatened? There are SIX reasons:
a) The first of the six reasons is NATURAL SELECTION. Explain how this can drive a popuation to extinction (think about failure to reproduce due to WHAT). Furthermore, why is the human influence causing extinction via natural selection FASTER? Think about the rate of mutations and how that isn’t keeping up with the rate at which ____ are changing!
b) The second of the six reasons is NON-CONTINGUOUS POPULATIONS. Non Continguous means not next to or touching another, usually a similar thing. With that meaning in mind, why might this lead to a population becoming extinct? Explain also how LITTLE _____ diversity of small populations therefore means they’re suceptible to a higher probability of extintion.
a) NATURAL SELECTION - This occurs when individuals LESS suited to a particular environment’s conditions fail to reproduce successfully. Numbers therefore decrease, and extinction can prevail.
The influence of humans on Earth is causing habitats to change faster than new mutation that can allow species to adapt to their envronment. Thus, they’re driven to extinction at a FASTER rate than before humans were around.
b) NON-CONTINGUOUS POPULATIONS - The total no. of a population’s numbers at a glance is sufficient, however, if groups of that pop. are isolated, they CAN’T interbreed and each group functions as a SEPERATE POPULATION. If however, there is LITTLE genetic diversity in each isolated group, then unfortunately, the seperated groups are suceptible to a higher probability of extintion.
Why can species be threatened? There are SIX reasons:
c) LOSS OF HABITAT.
Deforestation, drainage of wetlands, hedgerow loss, and sowing crops in autum instead of spring all lead to habitat loss. Explain How hedgerow loss can impact higher trophic levels in an ecosystem. Furthermore, What even is a hedgerow and why might they be removed? Lastly, explain fully how a decline in certain species of birds can occur as a result of farmers sowing crops in autum as opposed to spring.
c) Loss of habitat can also cause a population to go EXTINCT. There are 4 EXAMPLES of how loss of habitat can occur.
1) DEFORESTATION
2) DRAINAGE OF WETLANDS (Wetlands are natural, and functions as their own unique ecosystem!)
3) HEDGEROW LOSS - Hedgerows have seperated FIELDS for centuries. They provide a habitat for many. Their removal, often to accomodate large agricultural machinery. As a result of the loss, herbivores as well as consumers suffer as they lose out on smaller prey and plants. Thus, they decline in their numbers and this leaves a reduction in higher trophic levels as a result!
4) Farmers often sow crops in autum (i.e. they plant seeds in autum rather than in spring). As a result of this plants are unable to sustain a satisfactory height for certain birds to nest in. Thus, these brids see a decline.
Why can species be threatened? There are SIX reasons:
d) There are 5 examples of OVER-HUNTING. Give them all.
e) Competition from INTRODUCED SPECIES. Explain this using the exemplar of the DODO’s extinction.
f) POLLUTION - Explain how oil spillage can impact birds as well as fish in the sea… Furthermore, explain why artificial substances that can accumilate in a food chain are dangerous. They’re ________, __________ and ________ disruptors.
d) OVER HUNTING
- Trophy Hunting is a popular practice in certain nations across the globe.
- Some traditional medical practices use certain part of endnagered animals.
- Bush meat industry - Meat that is from wildlife hunted for human consumption.
- Overfishing
- Agricultural Exploitation
e) The introduction of certain species into a certain area can impact the native species negativley. E.g. Rats brought in by ships in the 17th century drove the DODO bird to extinction as rats consumed their eggs.
f) Oil shipped in LARGE tankers can sometimes accidentally discharge into the sea. This oil leakage then coats the top of the water acting as a barrier. As a result, the ‘barrier’ prevents oxygen ation of the surface of the water. Furthermore, some animals may break thorugh the ‘barrier’ and it results in them being coated in oil. Birds can sucumb to death as a result of this becasue the oil can clump up their feathers causing them to die of due to being chilled as their feathers cannot insulate their bodies!
Artificial substances can accumilate in the food chain. They can get INGESTED. They’re neurotoxins, carcinogenic and hormone disruptors.
CONSERVATION:
a) What is ‘conservation’?
b) There are 6 forms of CONSERVATION we shall look at. The first of which is the set-up of a GENE BANK. Which species are entered into _______ programmes to increase their numbers? What’s their grade (the 2 letters effectively a label given to a population depending on its rate of extinction).
c) SPERM BANKS - Why might a species be entered into a sperm bank donation apart from being critically endangered? Think of a selfish reason for humans to do this. There is an importance for society for their preervation and there is one word to pin its importance to society.
d) SEED BANKS - For what reasons is it critical to store seed banks - think about humanity in the evnt of a catastrophe…Since seeds are suceptible to degradation over time they’re periodically ________ and germinated.
e) EDUCATION
f) LEGISLATION
g) ECOTOURISM
a) Conservation is the PROTECTION, PRESERVATION, MANAGEMENT and RESTORATION of natural habitats. Its aim is to improve biodiversity while allowing simultaneous sutiable human activity.
b) EN graded species are protected and entered into breeding programmes to raise their numbers.
c) SPERM BANKS are used to store genes of ECONOMICALLY important animals who are threatended. They can be sent acorss the globe to be used in breeding programmes in other regions…
d) SEED BANKS are used to maintain the stock of seeds who may be vunerable (VU). Seeds must be thawed and germinated periodically - this is due to seeds being suceptible to degradation over time! Protecting seeds allows us to prepare for a catastrophe. certian plants are key to society’s survival and therefore their conservation is CRITICAL!
e) Education of society is key to ensuring the survival of habitats and species.
f) Legislation is key to ensuring that individuals do NOT destroy bidiveristy and it provides protction for EN species and areas.
g) Ecotoursim - repsonsible travel to natural areas that conserves the environment and improves the well-being of local individuals to that destination.
What’s the purpose of conservation? There are 4 reasons…
a) Ethical Reasons.
b) Agricultural Reasons
c) Environmental Reasons
d) Medicinal Potential
a) Ethical Reasons - Each species represents a particular combination of genes and alleles adapted to a particular environment and it’s considered that the uniqueness of each is VALUABLE.
b) Agriculture & Horticuture - Plants and animals use in agriculture and horticulture have been developed from those in the wild. Selective breeding INCREASES genetic UNIFORMITY this isn’t ideal. The loss of rare alleles is prevalent as a result.
c) Environmental Changes - Some alleles are MORE advantageous over others. They need to be preserved so that, that particular set of species can survive.
d) Medical Potential - If certain plant species that haven’t been studied are lost than we have no recolection of their medicinal value. This is a major loss.
Agricultural Exploitation.
a) Why is agriculture important generally speaking?
b) Why is the rate at which food is being produced rising in intensity and efficiency?
c) What examples can show how current agricultural practices are impacting the environment? There are 5 (one of them being covered already in the past cards).
a) Agriculture is essential to produce the quantity of food required for the survival of the increasing human population.
b) The way agricultural land is used, however, often conflicts with maintaining habitats and biodiversity. The efficiency and INTENSITY of food production are continually rising in order to meet demand levels. More land is being used, more pesticides, and more fertilisers are being used. Farms are also becoming increasingly mechanised.
c)
1. Hedgerows are being torn down in order to accomadate larger machinery.
2. Monoculture - in which vast amounts of one crop are being mass produced - cause a DECLINE in biodiversity as only 1 type of species can live there.
3. Crop yield plummets due to the same crop being grown on the same plot of land year on year. The roots are always at the same length, obtaining the same level of mineral from the same depth in the soil. So, farmers increase the usage of fertilisers to promote crop growth. This can result in eutrophication of nearby natural water bodies.
4. Since Monoculture is practiced farmers are aware that their crops are more suceptible to death via disease and pests. Therefore, more pesticides, insecticides and herbicides are used…
5. Overgrazing by cattle causes grasslands to become more unsustanable. Their hooves drive the air out and compact the soil resulting in the drainage being impacted.
Deforestation
a) What is deforestation? Why is it carries out? There are MANY reasons!
b) There are 6 major consequences to deforestation. EXPLAIN EACH (apart from 2)
1. Soil Erosion
2. Deforestation of UPLAND causes LOWLAND flooding
3. Impact on drainage, germination rate, rainfall and, nitrogen content of soil - due to FLOODING.
4. CO2 released BACK into the atmosphere.
a) This is the practice in which large scales of timber are obtained from the mass removal of trees from forests. The timber is utilised as a raw material for human consumption. Deforestation can also occur when land is cleared in order to make way for agriculture, roads, urban development and other infrastructure for human activity.
b)
1. SOIL EROSION = The removal of topsoil (which contains valuable minerals) occurs. Trees bind soil together. Deforestation on the higher slopes of valleys allows heavy rain to sweep the exposed top soil which contains valuable minerals and nutrients for sustenance - TOP SOIL is therefore regarded as the fertile soil. What remains is not suitable for plant growth.
- Deforestation of uplands causes lowland flooding.
- Under normal conditions, plants, leaf litter and humus all act as a sponge, soaking up the heavy rainfall, and water is only gradually released into the soil. Trees play a key role in ensure flooding doesn’t take place. They take up the water in large amounts in their TRANSPIRATION stream which at the end the water evaporates from the leaves and into the atmosphere… When trees are removed, the water sits at the top and can’t enter the soil as well as it could. What results is aerobic conditions being created in the soil favouring the pseudomonas bacteria who shall return nitrates back into the atmosphere which further reduces the quality of the soil. Only after a certain period does the water evaporate from the soil and as a result it diminishes the quality of the soil. It takes longer for the soil to warm-up. This causes germination rate to reduce as the soil is more colder on avergae as a result!
- LESS rainfall since water only returns to the atmosphere by the evaporation from the soil, not by transpiration. Evaporation is slow.
Habitat loss due to the removal of tree. As a result there is a reduction in the biodiveristy of the surrounding area. - Photosynthesising trees are cut down and cut trees may be burned or left to DECAY emitting CO2 back into the atmosphere.
OVERFISHING:
a) What is ‘overfishing’? What key example can be given regarding this? Think of the GRAND BANKS fishing area.
b) How does catching fish before they’re sexually mature cause a decline in the population of a fish species and a reduction in genetic diveristy?
a) The dramatic increase in the intensity and efficiency of commercial fishing has caused OVERFISHING in many areas of the world.
A very prominent example has been discussed before. The Grand Banks was among the most productive fishing areas in the World. Huge numbers of cod have been said to have prevented ships from moving thorugh the water in the 15th century! In the 50s however, huge trawlers, and the new technology, such as radar, were used. A huge propensity of fish were captured and as a result the numbers of cod declined significanlty.
b) Nets with very small mesh catch young fish before they’re sexually mature. As time goes by, there are fewer and fewer individuals left to reproduce and the population size decreases. It may become harder for remaining fish to find a mate and with a smaller number of them reproducing! The genetic diveristy reduces.
OVERFISHING - the effects on other wildlife…
c) Overfishing can impact the rest of the food chain - explain.
d) Regulations over fishning include WHAT 5 things?
c) Overfishing can imapct the rest of the food chain. If you remove the prey for another species, then you’re causing them (the species who eats the prey) to see a decline in their numbers.
d) Regulations over fishing include:
- Mesh sizes of the nets can be controlled.
- Quotas can be set to ensure only a certain number of fish are brought back to land and no more.
- Exclusion zones - i.e. prohibited fishing areas/ or prohibited times of the year when fihsing is not allowed - so that the population has time to regenerte its numbers.
- Legislation controlling fishing fleets
- Choosing fishfarming instead (but this comes with its consequences too)…
FISH FARMING:
a) Explain how fish are kept when they are farmed and the suitable requirements of fish farming…
b) What are 3 advantages to fish farming over the bush meet industry.
c) Despite the positives, don’t be fooled that there are no NEGATIVES. There are infact 5 we must be aware of. Explain each.
a) Aquaticulture contributes to about 95% of the salmon we eat. Farmed fish.
Fish are bred and grown in maturity ponds and lakes and are managed in enclousers where predation is reduced and the food supplies are constant. Articificial foods can be given to feed the fish. Fish are also grown in warm waters dischrged by factories as they can grown faster.
b)
1. Fish farming has a lower CO2 footprint.
2. A larger proportion of the bodies of fish are edible.
3. The efficency of conversion is higher in fish, therefore, greater biomass as a result since less is wasted!
c)
1. Diseased fish - Farmed salmon are often very densly stocked and so they can easily spread/transmit disease. Usage of pesticides to prevent diseases from emerging in the population in the beginning then imact the neighbouring living species!
2. Pollution - The ecological balance of the waterways may become upset . Eutrophication may occur due to the high levels of toxic waste emitted by the fish. The conc. builds up
3. Escaped fish - Farmed fish can be selected for rapid growth. If they then escape, they shall outcompete wild fish for food, habitats and mates. They can interbreed with other fish and therefore produce fast-growing populations which can push wild fish towards extinction.
4. Environmental Toxins - This can be a concern to humans who then consume the fish.
5. Environmental Degradation.
Sustainability & Decision Making:
a) What is environmental monitoring? Explain how the future of the environment can be predicted thorugh environmental monitoring.
b) Air Quality - How do we measure this? What species found on rocks and trees can help determine the air quality of the surrounding area?
c) Soil Monitoring looks at WHAT 4 things.
d) Water Quality
a) Environmental monitoring describes/assesses the quality of the environment. It establishes current status and when done repeatedly, the patter of the data can be used to identify trends and make future predictions about the state of the enviornment.
b) Air Quality - The conc. of pollutants in the air are measured because of the health impacts of their exposure with us. These pollutants can be carried out by the wind. Species of lichens on rocks and trees can indicate the levels of polluction within its area.
c) Soil Monitoring - This looks at the structure of the soil and the density of the soil. Furthermore, assessments of the water-holding ability of soil and the drainage capabilities are made.
d) Water Quality
Planetary Boundaries:
a) Define the term itself.
It’s a way of defining the ‘safe operating ‘________’ for ________’. There are __ processes that have been identified as to maintaining these _________ systems and the interaction of air, land and sea. Such systems are unpredictable and a _________ point may be reached if not careful. Once that tipping point is reached, it’s _______ to _________ the damage done. Exceeding ________ of the 9 planetary boundaries can lead to sudden catastrophic change to ________________ conditions.
What’s really interseting is that the study of planetary boundaries is inter-__________ (i.e. the _________, economic and other decsions shall take into account the ___________ of these boundaries in order to ensure that there is sustainable development and support to the _______ of the biosphere.
b) A _________ graph is a common way of displaying the ______ of these planetary _________. ____________ the green circle, is the ‘safe _________ ‘space’ for humanity’. Then, _________ the green circle and the outer red space/zone is an area of ___________ risk, the ‘zone of uncertainty’. ____________ the red circle, the values represent a high risk. The planetary boundary has been crossed and events are __________.
a) Planetary Boundaries are the limits between which GLOBAL SYSTEMS must operate to prevent ABRUPT, IRREVERSIBLE environmental damage. It’s a way of defining the ‘safe operating ‘spaces’ for humanity’. There are 9 processes that have been identified as to maintaining these planetary systems and the interaction of air, land and sea. Such systems are unpredictable and a tipping point may be reached if not careful. Once that tipping point is reached, it’s hard to reverse the damage done. Exceeding limits of the 9 planetary boundaries can lead to sudden catastrophic change to environmental conditions.
What’s really interseting is that the study of planetary boundaries is inter-disciplinary (i.e. the political, economic and other decsions shall take into account the existance of these boundaries in order to ensure that there is sustainable development and support to the health of the biosphere.
b) A circular graph is a common way of displaying the status of these planetary systems. Within the green circle, is the ‘safe operating ‘space’ for humaity’. Then, between the green circle and the outer red space/zone is an area of increasing risk, the ‘zone of uncertainty’. Beyond the red circle, the values represent a high risk. The planetary boundary has been crossed and events are uncertain.
Planetary Boundaries:
a) Climate Change is one of the 2 CORE boundaries and its planetary boundary has been crossed. Define CORE boundary.
b)
c)
a) Core Boundaries - Once crossed, the planetary boundary would drive the Earth into a NEW and unpredictable state with severe consequences for the biosphere.
b) Enough greenhouse gases have been added to the atmosphere that, even if emissions were to stop immediately, the average global temperature would still rise for decades. Kyoto Protocol of 1997 = 1st major interantional agreement to address global warming.
c) The CO2 that biofuels release on combustion has only recently been removed from the atmosphere. Growing more biofuel crops removes the CO2 from the atmosphere again. This contrasts with fossil fuels, which release carbon laid down 100s of millions of years ago. Biofuels are made by biological processes such as anerobic digestion of plant material or agricultural, domestic and industrial waste. They are useful in reducing the use of fossil fuels but growing plant material for them confilcts with the need to keep up with the growing demand for food. Also requires significant irrigation.
Further Issues:
1. Sustainable biofuel prodution relies on sustainable planting and efficient technical systems.
2. Deforestation to grow biofuel crops leads to soil erosion and biodiversity loss.
3. Reduction in water availability due to the irrigation intesive process involved in maintaing the plants.
4. Combustion produces MORE NO2 relative to fossil fuel’s production of NO2.
The process of its production:
1. Plant material is crushed and the stored starches (that are in the plant material) are digested with carbohydrates to release sugars.
2. Sucrose is crystalised. This leaves molusses rich in gluecose and fructose (molasses are sugar substitutes).
3. Gluecose and fructose are fermented by YEAST to PRODUCE a MIXTURE containing ETHANOL. This is anerobic fermentation of mixture containing ethano by the yeast.
4. The mixture is heated by burning the fibrous waste, or bagasse (sugar cane pulp), from the initial plant material and pure ethanol is then distilled.
