human influences on the environment Flashcards
what does making food production more intensive mean
producing food more efficiently with a finite amount of land and resources
what is an agricultural machinery and what has it done
tractors, combine harvesters
increased food supply
can harvest much larger fields
what are chemical fertilisers and what have they done
fertilisers increase the amount of nutrients in the soil for plants, meaning that they can grow larger and produce more fruit
increased food supply
what are insecticides and herbicides
are chemicals that kill off unwanted insects and weed species, meaning that there is less damage done to plants and fruit lost to insects (insecticides), as well as reducing competition from other plant species (herbicides)
what is selective breeding
animals and crop plants which produce a large yield are selectively bred to produce breeds that reliably produce high yields
what is monoculture farming?
means that on a given area of agricultural land only one type of crop is grown
the disadvantages of monoculture
there is very low biodiversity
increase in pest population
reduction in soil fertility
the disadvantages of insecticides
harmless insects being killed
pollution by pesticides (persistent chemicals which accumulate in food chains)
pests can become resistant to insecticides
biodiversity definition
number of different species that live in a particular area
what is a major cause of a reduction in biodiversity
habitat destruction
main reasons for habitat destruction
clearing land for farming and houses
extraction of natural resources
marine pollution
what are the downsides of deforestation
extinction/loss of biodiversity
soil erosion
flooding
increased carbon dioxide in atmosphere
consequence of soil erosion
without trees nutrients and minerals will remain in the soil and will wash away into water bodies by the rain
the loss of soil nutrients are permanent and makes it very hard for forrest trees to regrow
consequence of flooding
without trees the topsoil will be loose and can be easily washed away by the water, increasing the chance of flash floods and landslides
consequence of increased co2 in the atmosphere
contributing factor to global warming
what can untreated sewage cause in water
provides a good breeding ground for bacteria which increase rapidly depleting the oxygen dissolved in the water causing the death of fish
eutrophication
what can chemical waste cause in water
do not breakdown and can build up in foodchains poisoning the top carnivores
what can discarded rubbish cause in water
animals can eat the waste hindering the food chain
what can fertilizers cause in water
more algae which will consume the dissolved oxygen again leading to eutrophication
what can insecticides and herbicides cause in water
loss of biodiversity, can build up toxic concentrations and harm other animals
how does algal bloom affect aquatic plants
blocks the sunlight, preventing it from reaching the plants and hence they die
what are the negative effects of plastic pollution on land
As it breaks down, it releases toxins into the surrounding soil and as such the land is no good for growing crops or grazing animals.
how is acid rain formed
Combustion of fossil fuels that contain sulfur impurities creates sulfur dioxide
mixes with oxygen in air to form sulfur trioxide
sulfur trioxide dissolves in water droplets in clouds to form acid rain
what are the effects of acid rain
damage to leaves, killing plants
acidification of leaves, killing animals
increased risk of asthma attacks and bronchitis in humans
lowers ph of lakes when dissolved in them and kills fish
process of eutrophication of water
- increased availability of nitrate and other
ions - increased growth of producers
- increased decomposition after death of
producers - increased aerobic respiration by decomposers
- reduction in dissolved oxygen
- death of organisms requiring dissolved
oxygen in water
what is a sustainable resource
one which is produced as rapidly as it is removed from the environment so that it does not run out
which resources can be conserved and maintained sustainably
forests and fish stocks
how does methane and carbon dioxide emission pollute our atmosphere
methane and carbon dioxide act as a blanket around the atmosphere and trap gasses insulating the earth
causes global warming and climate change
polar/ice caps are melting
what is sustainable development defined as
development providing for the needs of an increasing human population without harming the environment
why have some organisms become endangered or have gone extinct
climate change, habitat destruction, hunting, overharvesting, pollution
and introduced species
how can endangered species be conserved
monitoring and protecting species and habitats
education
captive breeding programmes
seed banks
what are seed banks
seeds of endangered plant species are carefully stored so that new plants may be grown in the future
when can a species be at risk of extinction
if there is not enough genetic variation in the population as random changes in the environment may quickly cause extinction because the remaining organisms are all very similar and may not have the adaptations to survive such changes
why are conservation programs important
maintaining or increasing biodiversity
reducing extinction
maintaining ecosystem functions
what are the uses of Artificial Insemination and IVF
Both help maintain biodiversity
IVF: This allows gametes with known alleles to be used in ensuring the next generation remains biodiverse
Artificial insemination: This allows large numbers of offspring to be produced without the need for conventional sexual intercourse between males and females
what are the risks to a species
If its population size decreases, a species will experience reduced genetic variation
This renders the species more susceptible to environmental change
The species is less resilient and has a greater risk of extinction
Describe the negative consequences of letting untreated sewage flow into lake ecosystems
eutrophication
-aquatic plants die as sunlight gets blocked
-aerobic respiration of decomposers in the water reduce the amount of dissolved oxygen in the water
-reduced amount of dissolved oxygen kills fish
-food chain gets disrupted, more flies/mosquitos get habitats in or near the lake
-visual pollution
-toxicity caused by toxic or heavy metals polluting the water
describe the effect of deforestation on the animals that live in forests
habitat destruction
population decreases/migrates
loss of biodiversity
extinction
disruption of food chain
what causes populations to increase exponentially
birth rate greater than death rate
no limiting factors
few predators
plenty of food
Explain what happens to the energy that is absorbed by the vegetables but is not transferred
to humans.
some plants are inedible
eating by pests
plants lose energy by respiration
explain the likely consequences of an increase in the concentration of greenhouse gasses in the atmosphere
global warming
increase in rate of photosynthesis
causes an increase in plant growth/crop yield / vegetation
reduced biodiversity
how can sewage water be treated before entering a stream
screen
sediment
use microorganisms
flocculate to make particles clump together and easier to separate
chlorinate
explain how can fish stocks can be conserved by restocking
captive breeding programmes
release into protected areas
monitoring no of fish
limited fishing
State the names of three natural processes involving bacteria that are important to ecosystems.
nitrogen fixing
denitrifying
fermentation
explain the roles of bacteria in the filtration of water
secrete enzymes
breakdown of insoluble substances to soluble substances
breakdown of proteins to amino acids
break down of glucose to starch
break down fat to fatty acids and glycerol
aerobic respiration using oxygen and carbon dioxide released
