Transcript 3.2 Powerpoint

N4 Biology
Unit 3 Life on Earth
KA 3.2 Threats to biodiversity
Human effects on ecosystems
Learning Intention: Identify and describe how human
population growth is affecting biodiversity.
Success Criteria:
• Describe the effects of habitat destruction and give
examples
• Describe how overfishing affects ocean ecosystems.
• Explain what is meant by intensive agriculture, and how
it affects biodiversity.
• Describe the effects of climate change, acid rain and
pollution.
Human population growth
• Human population has been rising rapidly in the last
200 years.
Human population growth
The link below shows what the estimated human
population of the planet is today.
World population odometer
Can you think of any reasons why the human population
has increased so much in the last 200 years?
What has improved in the last 200 years which means
that people are surviving better?
Human population growth
• Here are some clues.
Vaccinations against disease
Better food availability
Better sanitation and
sewage treatment
Clean drinking water
Better disinfectants
More medicines and
better healthcare
Human demands on the planet
• Humans use up the
planet’s resources
such as water,
energy and land.
• We also pollute the
planet with our
waste.
• This effect that
humans are having on
the planet is called
the ecological
footprint.
Ecological footprint
• The more resources
you use and the more
waste you produce,
the bigger your
ecological footprint.
• What could
you do to
reduce your
ecological
footprint?
Reducing your ecological
footprint
• Use less energy – turn
the heating down or
insulate your home
better.
• Don’t waste water –
turn off a running tap
or spend less time in
the shower.
• Recycle as much waste
as you can.
Human effects on biodiversity
• The increasing human population is putting
more demands on the planet.
• More and more ecosystems are being
disrupted or destroyed altogether.
• Here are some examples of ways in which
humans are affecting ecosystems.
Biodiversity video clip
Habitat destruction
Deforestation video clip
Ecosystem management video clip
• Throughout the world,
huge forests are being
cut down to provide
timber and to create
space for farms, houses ,
factories and roads.
• These forests are home
to many different
species, so when the
forest goes they have no
food or shelter.
• Cutting down large areas
of trees like this is
called deforestation.
Overfishing
• Fish are an important
source of food for
humans.
• Some of the main fish we
capture and eat are
cod, haddock, herring
pollock and tuna.
• Overfishing of some of
these has caused their
numbers to decline.
Overfishing of Atlantic Cod
• The graph opposite
shows how the numbers
of Atlantic cod have
seriously declined since
the 1970s.
• There are now laws in
place in many countries
to prevent overfishing
and conserve valuable
species.
• This has helped the cod
numbers to start
recovering.
Intensive farming
• In order to feed a large
population, it is important
that we get the maximum
amount of food from an
area of land.
• This has led to intensive
farming techniques.
• This involves using huge
farms, and using lots of
chemicals to encourage
growth of plants
(fertilisers) and to kill
diseases (pesticides).
Intensive farming –
the problems
•
•
•
•
Pesticides kill harmful
insect pests, but also kill a
lot of useful insects.
Pesticides can leak into
rivers and harm animals
there.
Fertilisers make plants grow
faster.
If fertilisers leak into
rivers, they can cause
excessive growth of algae,
killing other species. This is
called eutrophication.
Intensive farming –
the problems
•
•
•
Intensive farming of
animals can lead to
overcrowded
conditions.
This affects the
health of the animals,
and they often need
to be given antibiotics
to prevent the spread
of disease.
These antibiotics can
then pass to humans
when we eat the
animal.
Intensive farming of beef
cattle
(expensive)
(good)
(bad)
(bad)
(bad)
Pollution and ecosystems
• Humans produce a lot
of waste which needs
to be disposed of.
• This includes rubbish
and sewage from our
homes, as well as
harmful chemicals and
gas emissions from
factories.
Write you ideas and examples on a post it note
Pollution from our homes
• Waste in our grey bins goes
to landfill sites. This can
cause toxic chemicals to leak
into the soil and kill animals
and plants.
• Waste water from our house
contains soaps and
detergents, as well as
everything that gets flushed
down the toilet!
• This water must be treated
to make it safe to release
into rivers.
• Poorly treated sewage can
also cause eutrophication in
rivers.
Recycling domestic waste
• By recycling as much waste
as possible, we can avoid
damage to the environment.
• Waste glass, metal, paper
and plastic can be remade
into new materials.
• Waste food and garden
waste can be used to make
compost. Some is also used
to produce biogas – an
alternative fuel.
Pollution from industry
• Power stations and factories
which burn coal and oil produce
acidic gases – sulphur dioxide
and nitrogen dioxide.
• These then dissolve in the
water in rain clouds.
• This then leads to acid rain,
often hundreds of kilometres
away from the source of
pollution.
• The acid rain can kill trees and
other plants. It can also cause
death of fish by causing lakes
to become acidic.
Pollution causes climate change
• Other gases released from
homes, cars and factories are
causing climate change.
• These gases are causing the
earth to slowly heat up – this is
called global warming.
• The gases involved are mainly
carbon dioxide and water
vapour. These are called the
greenhouse gases.
• By using less energy in our
homes, switching off
appliances not being used, and
using cars less we can help to
slow down this climate change.
Effects of climate change on
ecosystems and biodiversity
• Small changes in sea
temperatures are affecting
delicate ecosystems like coral
reefs, which are dying.
• Melting polar ice caps are
reducing the area for polar
bears to roam and find food.
• Rising sea levels are flooding
some coastal ecosystems,
destroying them.
• Some parts of the planet are
becoming drier, and the
animals living there cannot find
enough water to survive.
1. You must include:
2. You should include:
Examples of pollution
caused by humans and
how to reduce
pollution.
Causes of acid rain.
Causes of global
warming.
3. You could include:
Describe the effects
of acid rain and global
warming on plants and
animals.
Accidental pollution
• Some industries produce
harmful chemicals which need
to be safely disposed of.
• These chemicals sometimes
need to be transported to
where they will be dumped.
• If they accidentally leak into
the environment, ecosystems
can be seriously affected.
• This will reduce biodiversity in
that area.
• Transporting oil in oil tankers
at sea can also affect wildlife
if there are any accidental
spillages.
Natural effects on biodiversity
Learning Intention: Identify and describe how natural
disasters can affect biodiversity
Investigate issues around conservation of endangered
species
Success Criteria:
• Give examples of natural disasters that can affect
ecosystems
• Give examples of endangered species
• Describe ways of conserving endangered species
• Explain the importance of conservation of species.
Natural forms of pollution
• Some natural disasters can
have negative effects on
biodiversity.
• Forest fires can start in hot
dry countries in the summer
months and spread over vast
areas, destroying ecosystems.
• Earthquakes, volcanos,
tsunamis and severe storms
can also damage plant and
animal life.
Endangered species
• The numbers of
many animals on the
planet are declining
due to overhunting
and habitat
destruction.
• Some of these
species could soon
become extinct.
These are called
endangered species.
Endangered species
Conservation of endangered
species
• Governments throughout
the world have taken
steps to protect
endangered species by:
- passing laws making it
illegal to hunt or kill
certain animals.
- making it illegal to pick or
destroy certain plants
Conservation of endangered
species
-
Creating protected areas like
wildlife reserves and national
parks, where animal and plant
numbers are monitored and
rangers patrol to ensure that
animals are not harmed.
-
Having captive breeding
programmes, where endangered
animals are fed well and
encouraged to breed, and the
young animals are protected from
natural predators.
Case study of an endangered
species
- Choose an endangered animal from the list on the next slide, or
come up with your own suggestion for an endangered species.
- Create a powerpoint presentation or a word document about the
animal.
- Include where the animal’s natural habitat is, why the animal is
in danger of becoming extinct and what steps are being taken
to conserve the species
- Make it bright and colourful with lots of pictures.
Case study of an endangered
species
-
Amur Leopard
Black Rhino
Hawksbill Turtle
Javan Rhino
Leatherback Turtle
Mountain Gorilla
South China Tiger
Sumatran Elephant
Sumatran Orangutan
Sumatran Rhino
Sumatran Tiger
Amur Tiger
Asian Elephant