Understanding Our Environment

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Understanding Our Environment
(OCR)
W Richards The Weald School
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Taking Population Samples
Using different sampling techniques we can
measure the population in a given area, for
example
Help!
Help!
Using traps
Taking animal samples
Taking samples using quadrats
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Ecosystems
An Ecosystem is a physical environment with a
particular set of organisms living in it. They
can be natural, e.g. a woodland, or artificial,
e.g. a greenhouse.
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Classification
The world is populated by millions of different
species of animals and plants
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Classifying organisms
All organisms are classified into groups. For
example
Organism
Plants
Animals
Vertebrates
Invertebrates
Reptiles
Fish
Birds
Mammals
Amphibians
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Classification Difficulties
Some organisms do not fit into an obvious
category. For example...
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Variation
Species means a group of similar organisms,
e.g. dogs
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Reproduction between species
Liger
Mule
Geep
Zebroid
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Similar Species
Ways in which sharks and dolphins are similar
Ways in which sharks and dolphins are different
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Photosynthesis
PHOTOSYNTHESIS is when a plant makes its own
food. Photosynthesis USES Carbon
dioxide Water Energy (from the sun) Photosynthesi
s PRODUCES Oxygen Glucose
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Photosynthesis
SUNLIGHT
Gives the plant energy
CHLOROPHYLL
The green stuff where the chemical reactions
happen
WATER
Travels up from the roots
CARBON DIOXIDE
Enters the leaf through small holes on the
underneath
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Photosynthesis Equations
The GLUCOSE produced by photosynthesis is used by
the plant for _______ (through ____________). It
is stored in the plant as ___________.
Words respiration, starch, water, oxygen, energy
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Factors Affecting Photosynthesis

• Temperature the best temperature is about 300C
  anything above 400C will slow photosynthesis
  right down
• CO2 if there is more carbon dioxide
  photosynthesis will happen quicker
• Light if there is more light photosynthesis
  happens faster

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Drawing graphs of these factors
1. Temperature
2. Carbon dioxide
3. Light
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What is the glucose used for?
1) Glucose (sugar) can be used to make long
chains of insoluble starch
2) Glucose can be used to make cellulose for
cell walls
3) Glucose can be combined with nitrates to make
proteins (for growth)
4) Glucose can be converted into lipids (fats or
oils) to store in seeds
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Respiration
As well as photosynthesis, plants also undergo
respiration
The plant uses this energy to work, grow and
reproduce.
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Competition
Any living species competes with each other.
They may compete for
Get off my land
- Living space - Food - Water
In addition to this competition, the population
of a species can be affected by predators,
disease, migration etc
Yum!
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Food chains
A food chain shows where the energy goes in a
food chain (in other words, what gets eaten by
what)
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Predators and Prey
A PREDATOR is an animal that hunts and eats
another animal The PREY is the animal it eats,
for example
Hey! I ordered a steak
Prey
Predator
Consider the populations of these two animals
over time
Rabbit
Fox
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Interdependent Relationships
1) Parasitic relationships
2) Mutualistic Relationships
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Adaptation
Organisms are ADAPTED to the habitat they live
in. In other words, they have special features
that help them to survive. Some examples
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Evolution
Evolution is the slow, continual change of
organisms over a very long time. All living
things on the Earth have developed from the first
simple life forms that arrived 3,000,000,000
years ago.
Charles Darwin (1809-1882)
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Evolution

• My key observations
• All living things produce more offspring than
  survive to adulthood
• In spite of this, population sizes remain roughly
  constant
• Variation exists among species
• Characteristics can be passed on from one
  generation to the next.
• These observations led me to the conclusion that
  species evolve over a along period of time by a
  mechanism called Natural Selection. The main
  evidence for this is from fossil records.

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Natural Selection
1) Each species shows variation

1. There is competition within each species for
   food, living space, water, mates etc

Get off my land
Gutted!

1. The better adapted members of these species are
   more likely to survive Survival of the Fittest

Yum

1. These survivors will pass on their better genes
   to their offspring who will also show this
   beneficial variation.

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Darwin vs Lamarck
Darwin wasnt the first to come up with evolution
he was simply the one credited with explaining
how it worked (i.e. Natural Selection). An
earlier scientist called Lamarck explained
evolution by different means
The giraffe has a long neck because it
stretches its neck to reach the food, and these
long necks are passed on to their offspring.
Organs which arent used will eventually
disappear.
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An example the peppered moth
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A smaller example
Consider the four steps of natural selection in
the example of some bacteria that has become
resistant to penicillin

1. Variation some strains of bacteria are
   resistant and some arent.
2. Competition The non-resistant bacteria are
   killed by the penicillin.
3. Survival of the fittest the resistant bacteria
   survive.
4. Passing on of genes the resistant bacteria
   reproduce and pass on their adaptations to their
   offspring.

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The Evolution Tree
Family Hominidae (Great Apes)
Family Hylobatidae (Lesser Apes)
Subfamily Hominidae
Subfamily Ponginae
Tribe Homini
Tribe Panini
Tribe Gorillini
Humans
Chimpanzees
Gorillas
Orangutans
Gibbons
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Evidence for Evolution
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Population and Pollution
The human population is growing exponentially
This has a number of effects on the environment
Land less land and water available
Building more buildings needed
Quarrying and mining raw materials and sources
of energy are being used up
Waste more waste needs to be disposed of with
more pollution
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Ozone
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Pollution
Humans pollute the Earth in a number of ways
Water with sewage, fertiliser or toxic
chemicals Air with smoke or gases such as
sulphur dioxide Land with toxic chemicals,
pesticides and waste
NO, NO2 and CO
These gases produce acid rain (which affects
tress and buildings) and worsens the greenhouse
effect
Power stations produce CO2, SO2 and NO2
Cars produce NO, NO2 and CO
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The Greenhouse Effect
We get heat from the sun
Words methane, radiated, absorbing,
deforestation, waste, greenhouse
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Pollution Indicators
Lichens can be used as air pollution indicators
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Pollution Indicators
The quality of water can be monitored by looking
at the species of insect in the water
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Sustainable Development

• Sustainable development is all about preserving
  the world for tomorrow. There are three main
  strands
• Economic development
• Social development
• Environmental protection

• Examples of sustainable development include
• Replanting trees after chopping them down
• Limiting the number of fish allowed in a catch
• Protecting endangered species

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Extinct Species
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Endangered Species
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Protecting Endangered Species
Ways of protecting endangered species