Human Influences on the Environment

Question 1

which species has been the most successfull in populating the earth

Answer 1

Amongst species, homo sapiens, us humans have been one of the most successful at populating the Earth

Question 2

why have humans been the most successfull in populating the earth

Answer 2

The reason for this is intellect
Early humans invented tools to make life easier - today technology is so much complex - we now have a variety of ways that we pollute the Earth’s air, soil and water

Question 3

what demands from humans have been increasing (3)

Answer 3

We have been making increasing demands from Earth for:
raw materials iron coal copper etc
wood
energy, electricity biomass etc, fossil fuels
food
space for habitat - we need to space to build homes, schools, leisure centres, factories shopping malls etc
Space to dump our rubbish (landfills)

Question 4

what are some examples of interaction in a modern farm ecosystem (5)

Answer 4

A modern farm resembles a managed ecosystem (many interactions are the same as in natural ecosystems)
Examples of interaction on a modern farm:
humans with wind, windmills
humans with temperature humidity for crop growth
humans with light intensity for crop growth
humans
Plants depend on light and nutrients/mineral ions in the soil, etc for growth
Stock animals (cattle, pig, sheep) depend on the plants for food
Farmers can also use their crops to manufacture products into bread, cereal, margarine

Question 5

what are some factors farmers control to maximise crop yield regarding soil ph

Answer 5

light intensity, temperature, CO2 levels –> only thing they can do is plant in places with a lot of light - otherwise there’s not much to do with field crops. HOWEVER, they can use a greenhouse/glasshouse or a polytunnel where they can control all of these
Soil pH - different plants grow in different soil pH - putting a plant in soil of the wrong pH reduces the uptake of mineral ions.

Question 6

what is the solution to control soil ph

Answer 6

Solution - if the soil is too acidic you add lime (calcium salts). Not many soils are ‘too alkaline’

Question 7

how do farmers control soil ions

Answer 7

Soil Ions - You increase ions in the soil so that more can be taken up and used for growth by making protein (this is for nitrates)

Question 8

how do farmers control soil structure

Answer 8

Soil structure - soil with good aeration and drainage allows for good uptake of mineral ions and water
Solution: ploughing of fields to break up compacted soil, add manure to improve drainage, aeration of heavy clay soils

Question 9

what is the solution to control soil ions

Answer 9

Solution - add fertiliser or grow it in a hydroponic culture

Question 10

what are some ideal methods to control factors (2)

Answer 10

Glasshouses/polytunnels are ideal to control factors are:
The walls being transparent means they can allow in enough natural light for photosynthesis, but also in the winter when there is less natural light, you can create a ‘longer day’ using artificial light’
Plants can be grown in a hydroponic culture to provide the exact balance of mineral ions for specific crops

Question 11

what effect to glasshouses have

Answer 11

Glasshouses also have a greenhouse effect - short wavelength infrared radiation that enters the glasshouse is trapped/absorbed and re-radiated as longer wavelength infrared radiation. This heats the glasshouse up
In winter if the outside temperature is too low, the greenhouse can be heated using heaters etc

Question 12

how do radiators using fossil fuels decrease transpiration

Answer 12

If the heaters use fossil fuels, they produce CO2 and water vapour. The water vapour in the air of the glasshouse creates a moist environment reducing water loss in plants via transpiration.

Question 13

what is the problem with excess heat

Answer 13

Excess heat beyond the temperature at which crop yield is increased is a waste of money

Question 14

what do farmers do to tackle using excess fertiliser

Answer 14

Excess fertiliser is a waste of money - to make sure they don’t do this, farmers monitor the amount of fertiliser added to ensure MAX growth and yield of the plants, but not excess

Question 15

label nitrogen cycle

Answer 15

Nitrogen cycle on a farm - make a flashcard - answer is sent to whatsapp

Question 16

what are 2 main tyes of fertilisers

Answer 16

Two main types of fertilises = organic and inorganic

Question 17

what are organic fertilisers

Answer 17

Organic fertilisers = made from the faeces of animals mixed with straw. E.g. farmyard manure

Question 18

what are inorganic fertilisers

Answer 18

Inorganic fertilisers = inorganic compounds like potassium nitrate or ammonium nitrate - designed to give a specific amount of nitrate when farmer uses according to manufacturer’s instructions

Question 19

Differences between organic and inorganic fertiliser (2)

Answer 19

With organic fertiliser, only a small proportion of nitrogen lost is returned to the soil, as some becomes part of the animals. So most farmers apply inorganic fertilisers to replace the nitrogen and other mineral ions lost
Inorganic fertilisers cannot improve soil structure like organic fertilisers as they don’t have any decaying matter which is an essential part of soil

Question 20

an alternative to fertilisers?

Answer 20

An alternative to fertilisers for replacing lost nitrates is to grow a legume crop (clover) one out of every four years
Legumes have nitrogen fixing bacteria in their root nodules –> these bacteria convert nitrogen gas in the soil air into ammonia. This is oxidised to become nitrate, which then becomes available for next year’s crop.
Farmers can use crop rotation to do this

Question 21

what is a pest

Answer 21

Pest = organisms that reduce the yield of crops or stock animals

Question 22

what is yield

Answer 22

Yield = amount produced for sale
A pest can reduce/harm the yield by:
lowering the amount by reducing the

Question 23

how can a pest lower the yield

Answer 23

growth - by eating it and damaging it, or by reducing photosynthesis (happens if leaves are eaten)
lowering the appearance or quality of a crop - making it unsuitable for sale

Question 24

what are some other pests and their killers(5)

Answer 24

Pathogens can also be pests - bacteria, virus, fungi, protoctists, animals and plants
Pesticides = chemicals used to kill pests
Herbicides = kill plant pests (weedkiller)
Insecticides = kill insects
fungicides = kill fungi
molluscicides = kill snails and slugs

Question 25

what is a weed

Answer 25

A weed = a plant that grows where it is not wanted - these can be controlled mechanically as well - physically removing the weeds Pests can also be used using biological control

Question 26

what is monoculture

Answer 26

Monoculture = when a large area of land is cultivated with a single crop

Question 27

why do farmers use monoculture

Answer 27

Farmers use monoculture to make harvesting easy

Question 28

what is problem with monoculture

Answer 28

With monoculture, a pest can go through and affect an entire field rapidly.

Question 29

why are pesticides sometimes inefficient against pests

Answer 29

The same way bacteria develop antibiotic resistance through mutations, pests can also develop resistance to the chemical through natural selection

Question 30

what are some Ways that pesticides cause damage to the environment (4)

Answer 30

Pesticides can remain in the environment for a long time - they are hard to decompose Bioaccumulation = pesticides build up in living organisms Biomagnification = the pesticides build up and become more concentrated along the food chain Pesticides might not be harmful to only one species - they may also kill other insects, and even helpful species like bees

Question 31

why is bioaccumilation bad

Answer 31

--> pesticides can enter lakes, rivers, ponds and enter fish. An animal will eat 1000 fish over its lifespan, and so the chemicals in all of those fish end up in the animal. The human who eats that animal(s) in their lifespan will also get the chemicals from those animals in them

Question 32

what should an ideal pesticide do (6)

Answer 32

An ideal pesticide should: control the pest effectively be biodegradable should not accumulate in living things should be specific to the targeted pest so that ONLY that pest is killed easy to apply be safe to transport, store and apply

Question 33

what is biological control

Answer 33

Biological control = when an organism is used to control (decrease the number of) pests like a cat eating mouse

Question 34

give an example of biological control for whiteflies

Answer 34

Tomatoes can be infested with a pest called whiteflies A tiny wasp called encarsia parasitises destroys the larvae of the whiteflies. To reduce the number of whiteflies in a tomato infestation in a greenhouse, you can just introduce the encarsia tiny wasp.

Question 35

what is biological control used for compared to pesticides

Answer 35

- this is a biological control This method won’t destroy every single one --> biological controls aren’t used to eliminate a pest population, but to significantly reduce the number down.

Question 36

give an example of attracting the pest to destroy it

Answer 36

pheromones - use synthesised pheromones to attract pests to traps, where they are then destroyed

Question 37

give an example for using a natual predator for biological control

Answer 37

introducing a natural predator (cats for rats, ladybirds for aphids) introducing a herbivore

Question 38

give an example for using a parasite for biological control

Answer 38

parasite - encarsia white fly infesting tomatoes

Question 39

give an example for using a pathogenic organism for biological control

Answer 39

a pathogenic microorganism - rabbit population controlled with myxomatosis virus

Question 40

how can male sterility be used to biologically control organisms

Answer 40

sterile male - (sterile=infertile) - the males will mate with the females, but no offspring will be formed

Question 41

what has happened to fish demand

Answer 41

Demand for fish has increased rapidly Fish populations have decreased dramatically, as well as species of fish

Question 42

how is aquaculture not all for humans

Answer 42

Aquaculture - fish farming, allowed this demand to be met easier than before Fish like salmon, cod, sea bass, trout etc are all farmed on fish farms but this NOT ALL for humans - a large part of this is used for animal food, as fish is a good source of protein

Question 43

how is aquaculture used to farm fish (5)

Answer 43

Aquaculture is used to farm crustaceans like prawns and lobsters as well Fish are kept in tanks, enclosures in rivers and lakes, or sea cages Fish are really densely packed together Fish are kept separated by size - bigger fish of the same species may eat the smaller fish Fish farming advantages: - water quality can be monitored

Question 44

what are some factors u can control in fish farming

Answer 44

Factors you can control: oxygen levels, temperature, water clarity, and chlorophyll in the water

Question 45

what are the dangers for algal bloom in fish farming

Answer 45

High chlorophyll concentration in the water can suggest/give a ‘warning’ of an algal bloom This is a problem as an algal bloom is toxic to fish

Question 46

how is fish farming better than wild fish (2)

Answer 46

Compared to wild fish, with fish farming, you can control what you feed the fish (the quality) and how often you are feeding the fish Selective breeding programmes can be used in fish farming to breed fish that grow quicker, or grow to a bigger size, or are less aggressive than wild fish

Question 47

what are some problems with densly populated fish farms

Answer 47

Problems with fish farming: As these fish are farmed so densely, disease is much more likely to spread through the fish much more rapidly So to eliminate this problem, antibiotics are used

Question 48

why is using antibiotics in water for fish farms hazardous

Answer 48

These antibiotics may not be completely degraded by the time that humans eat these fish, so this contributes to antibiotic resistance

Question 49

how can fish farms cause water pollution (3)

Answer 49

fish faeces, and the waste from fish food pollutes the outside waters to the fish farm and can lead to eutrophication Pesticides used to kill fish parasites can be very toxic to other non-harmful non-vertebrates as well Fish farming can be very harmful to wild fish, as a lot of wild fish is needed to feed a little bit of carnivorous farm fish Salmon and sea bass are examples of carnvirous farm fish

Question 50

what is pollution

Answer 50

Pollution = contamination of the environment by harmful substances that are produced by the activity of humans

Question 51

how do CO2 levels vary in the summer

Answer 51

CO2 levels drop due to increased photosynthesis from light intensity, and higher consumption of CO2 by plants. although plants respire, in the summer they photosynthesise at a much higher rate

Question 52

how do CO2 levels vary in the winter

Answer 52

in the winter CO2 levels rise as there are less plants photosynthesising, so there is less CO2 being consumed and more CO2 in the atmosphere due to animals respiring

Question 53

How have CO2 levels risen over the last century and what does it contribute to

Answer 53

CO2 levels have risen dramatically over the last century - this increase is mainly due to burning fossil fuels This has led to the Earth warming up due to the greenhouse effect and global warming

Question 54

what makes global warming worse and why

Answer 54

This is made even worse by the deforestation occurring in large areas of tropical rainforests Tropical rainforests are called the ‘lungs of the Earth’ as they absorb a LOT of CO2 from the atmosphere - this means with extensive deforestation, a lot less CO2 is being absorbed from the atmosphere making things even worse

Question 55

what are sme additional greenhouse gases

Answer 55

Additional greenhouse gases are nitrous oxide (N2O) and CFC (Chloroflurocarbons) CFCs are manmade - only produced by human activities

Question 56

what happens to long wavelengths when reaching earth

Answer 56

some long wavelenghs are lost into space and some long wavelengths are trapped by greenhouse gases and emitted back to earth

Question 57

what happens to short wavelengths when reaching earth

Answer 57

short wavelengths are re emitted as long wavelengths back to earth, some can be lost in space

Question 58

where are CFCs used

Answer 58

CFCs were used in fridges, spray cans (aerosols), solvents and packaging material like foam packaging, before they were banned.

Question 59

why were CFCs banned

Answer 59

CFCs were banned as they damaged the ozone layer, in the upper layer of the atmosphere

Question 60

why is the ozone layer important

Answer 60

This is quite important as the ozone layer is what reduces the amount of UV radiation that reaches the Earth’s surfaces

Question 61

what are the effects of earth warming up (5)

Answer 61

Effects of the Earth warming up: Polar ice caps will melt and so sea levels would rise Ocean currents would change, leading to warmer waters will flow into areas that were previously Long term climate change can occur - the temperature across many different regions would change, so in some areas the amount of rainfall would increase, and in some the amount of rainfall would decrease --> in the areas that it increases, this is because the higher temperature means more water is evaporating from the surface of the sea It could change the nature of a lot of ecosystems --> this could lead to species becoming extinct, if the species do not adapt fast enough, or migrate to a more appropriate setting fast enough Changes to farming - different plants are best grown in different temperatures. Alos with a higher temperature, more pests are available

Question 62

how is methan produced

Answer 62

Methane is produced when microorganisms ferment large organic molecules to release energy

Question 63

what are the sources of methane (3)

Answer 63

Sources of methane: 1. cows - fermentation by microorganisms in the stomach of cattle (or other animals that have 4 or more stomachs) 2. rice paddies - fermentation of bacteria in rice fields 3. landfill sites - decomposition of waste buried in the ground When burning petrol or diesel in vehicle engines, carbon monoxide are produced when there is insufficient oxygen

Question 64

how is cabon monoxide dangerous (2)

Answer 64

Carbon monoxide is dangerous as it is colourless, odourless and tasteless, so it can invade the body undetected In the body, carbon monoxide has a higher affinity with haemoglobin compared to oxygen, so it displaces oxygen in the red blood cells

Question 65

what are the symptoms of carbon monoxide poisoning

Answer 65

A person with carbon monoxide poisoning can lose consciousness and even die due to the lack of oxygen reaching vital organs like the brain and the heart

Question 66

how is sulfur and nitrogen oxides releases (3)

Answer 66

Sulfur dioxide is sometimes released when you burn fossil fuels, due to sulfur impurities Both sulfur dioxide and oxides of nitrogen are released into the atmosphere from volcanic eruptions Nitrogen oxides can also form from lightning

Question 67

how is sulfur and nitrogen oxides bad for the environment

Answer 67

Sulfur dioxide and oxides of nitrogen dissolve in water vapour in the atmosphere, and they fall as acid rain Normal rain IS slightly acidic (5.5), so acid rain is even more

Question 68

how can people use biological organisms for sulfur or nitrogen pollution indicators

Answer 68

Lichens (small moss-like organisms) can be sensitive to sulfur dioxide pollution There are indicator species that can indicate the different levels of sulfur dioxide pollution, and are used for this purpose in countries