NATURE PRESENTATION
Sara Podda
Created on May 23, 2023
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Transcript
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PRESENTAtion
Humans and the envirionment
questions
endangered species
conserving endangered species
conserving forests/fish stocks
sustainable development
trickling filters and activated sludge
sewage treatment
recycling
resources
conservation
other types of waste
pesticides
fertilisers
eutrophication
nuclear fall-out
Index
NUCLEAR FALL-OUT
- Accidents at nuclear power stations release radioactive substances into the atmosphere
- Radioactive substances can cause sickness and burns becouse of ionising radiations that damages the DNA molecules in living cells
- Ionising radiations are: alpha, beta and gamma
- Aquatic organisms live in aquatic habitats and respire aerobically so need oxygen
- Fertilisers and untreated sewage cause pollution in fresh water
- Fertilisers contain nitrates, soluble in water, and phosphates
- When nitrates are leached, may run into streams and rivers causing the rapid growth of algae and green plants until they cover the surface
EUTROPHICATION
- Light will not reach the plants on the bottom so they will die with the plants in the surface
- This will be a source of food for bacteria (decomposeres)
- They will breed rapidly using oxygen
- There will be little oxygen for other living organisms who will move or die
- This process is called eutrophication and can happen whenever food for plants or bacteria si added to water
INORGANIC ONES
- Nitrate fertilisers permit to have higher yields to make more profit
- Cause a lot of pollution for the envirionment
- To prevent this, inorganic fertilisers have to be used:
- in the right amount so plants can absorb them
- when will not rain
- when plants are growing so not on empty fields
- distant from streams and rivers
ORGANIC ONES
FERTILISERS
- Organic fertilisers such as manure don't contain many nitrates and release nutrients gradually
- Crops with organic fertilisers are greater than crops with inorganic ones so they are more expensive and someone can't afford it
- If are not used correctly they can still cause pollution
- Are substances that kills organisms which damage crops
- Insects ---> killed by insecticides
- Fungi ---> killed by fungicides
- Weeds ---> killed by herbicides
- Insects and fungi can feed on a monocolture so have inexhaustible food supply
- Are harmful substances for the envirionment and an example is DDT
- The use of DDt was stopped and banned in some parts of the worls
PESTICIDES
FEMALE CONTRACEPTIVE HORMONES
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- Hormones containing oestrogen can be taken by women as a method of birth control
- Some of these hormones will be excreated in woman's urine and will go in sewage
- Fish and molluscs can be affected by these contraceptives becouse prevent the testosterone working effectively
- In the last 20 years the sperm count is fallen but no-one knows the real causes
NON-BIODEGRADABLE PLASTICS
- Are man-made materials used for many things
- Are made from fossil fuels
- Are: cheap, lightweight and can have every shape and colour but are non-biodegradable
- Can be very dangerous for animals in aquatic habitats
CHEMICAL WASTE
- Discharge of chemical waste into rivers is a type of pollution
- Can contain heavy metals that are very toxic for living organisms
- If enters in aquatic habitats will kill every living organism
OTHER TYPES OF WASTE
The process of looking after the natural environment
- It attempts to maintain or increase biodiversity
- Loss of habitats--->greatest threats to biodiversity
- Habitats under threat: tropical rainforests & wetland
- We build roads and houses destroying what used to live on that land
- We farm animals in large numbers
- Many governments and world-wide organisations are attempting to make sure that especially important habitatas aren't damaged
Conservation
non-sustainable resources
Resoruces that once used, they have gone foreverMade by compressing partially decayed bodies of plants and bacteria that lived in the Carboniferous period
sustainable resources
A resource that can be removed from the environment without it running oute.g. fish in the sea wood for fuel
resources
People will always need resources we take from our environmentIf careful we can take and use these resources without causing harm to other organsims
- made of cellulose fibres from plants
- waste paper is mixed with water+ chemicals to form a pulp, which is passed through filters and treated to leave clean cellulose fibres
- we get metals from ores found underground
- mining metal ores uses lots of energy + non-renewable resources
- metals can be recycled
- made from fossil fuels
- we can resuse plastic objects or recycle them
metals
paper
plastics
glass
- made by heating at very high temperatures sand + other chemicals
- used glass can be crushed, melted at high temperatures and then used to make new objects
Recycling
sewage= waste liquid coming from houses, bathrooms, roads and citiesraw sewage= untreated sewagesewage treatment enables water to be recycled
Sewage treatment
Process: 1)Raw sewage passes through screens which trap large objects 2)Screened liquid is left in settlement tanks 3)Insoluble particles drift to the bottom and from sediment
- the liquid from the settlement tanks run into an aeration tank
- these contain aerobic microorganisms that make the sewage harmless
- oxygen is provided by bubbling air through the tank
- sludge is acted on by anaerobic bacteria
Activated sludge
- the liquid from the settlement tanks is trickled over a trickling filter bed
- passes onto the sruface of the stones through holes ina a rotating pipe
- aerobic microorganisms live on the surface of the stones, they feed on nutrients in the sewage
- clean water drains out of the bottom of the bed
Trickling filters
sustainable development = providing for the needs of an increasing human population without the environment
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Sustainable development
Humans have probably always used fish as a source of hagt-protein food.
- if we do not reduce cathes, the populations will get so small that there will not be enough adult fish left to breed and sustain the popiulation
- one system of controlling the numbers of fish caught is to impose quotas
- another way is to breed large number of themin fish hatcheries
Conserving fish stock
It is possible to use forests sustainable.
- Governments can refuse to grant licences to companies who want to cut down valuable forests
- no clear-felling but selective felling
- trees can be cut down to about 1 metre or less = coppiced
- where large number of trees are cut down, new ones should be planted to replace them
- education is important to people
Conserving forest
Introduced species
Pollution
Hunting
Habitat destruction
new species that are introduced by humans into an ecosystem can threaten the existence of native species
addition of extra carbon dioxide and methane to the atmosphere is causing climate change, this is one of several factors about the extinction of the golden toad
Humans have always hunted animals for food, but sometimes this hunting is so severe that it can destroy an entire species
human activities can destroy habitats. Species with no habitat cannot survive. When huge number of species seem to have become extinct = called mass extinction
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Endangered species
Many tactics can be used to conserve endangered species:
- monitoring and protecting the species in its natural habitat
- using captive breeding programmes
- educating local people about the importance of conservation, and what they can do to halp
- bulding up seed banks
Conserving endangered species
QUESTIONS
QUESTIONS
QUESTIONS
by Antoniello Melissa, Podda Sara and Tramonti Sofia
Thanks!