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Mind Map by Cara Dowling, updated more than 1 year ago
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Created by Cara Dowling
over 10 years ago
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B3: Life on Earth
- Lesson 1:Life,
Classification and
Adaptations
- Classification: Method of
organising all living organisms in to
group, e.g. the 5 kingdoms; Animal,
Plant, Bacteria, Fungi, and Protoctista
(single celled organisms).
- Classification is used to:
1) make sense of the
huge range of organisms
on our planet, 2) show
different relationships
between different species
- Classification is used to:
1) make sense of the
huge range of organisms
on our planet, 2) show
different relationships
between different species
- Species Classification: A
species name is made up of
two parts, Genus and Species,
e.g. Homo Sapiens.
- Species: Two organisms with similarities that
breed together to produce fertile offspring. E.g. A
horse and a donkey belong to the same genus
but different species. They can breed, but their
offspring (mule) are infertile. (Also tigrons and
ligers).
- Adaptations: Adaptations are characteristics
of organisms that aid their chances of
survival. Different environments and/or
situations favour different characteristics.
Organisms with these characteristics will
survive and breed and pass on 'good' genes to
their offspring. This is evolution.
- There is a huge variety of living
organisms on Planet Earth. We can
classify them (put them into groups)
according to their similarities and
differences in characteristics such as
physical features and the chemical
structure of molecules such as DNA.
- Classification: Method of
organising all living organisms in to
group, e.g. the 5 kingdoms; Animal,
Plant, Bacteria, Fungi, and Protoctista
(single celled organisms).
- Lesson 2:
Food Webs
- Predator- Kills and feeds
off other living animals
- Trophic level- Feeding level
- Detritivore- Feeds on daed and decaying
material ( are animals)
- Decomposer-Feeds on dead and
decaying material (are bacteria/ fungi)
- Omnivore- Eats plants like a
herbivore and meat like a carnivore
- If we measure the biomass of all the organisms in
each trophic level of a food chain, we can draw a
pyramid of biomass. This usually shows that the
total biomass of one trophic level is less than that
of the level it feeds on. This is because some of
the energy is transferred from the organisms to
the environment as heat energy during
respiration.
- Interdependence of organisms: Organisms
depend on each other and on the
environment for their survival. However, if
different species live in the same habitat
they will compete with each other for limited
resources such as food, water and mates.
- Food Web- A diagram that shows
all of the feeding relationships
between the different species in
an ecosystem.
- Food webs are generally stable unless; 1) The environment
changes considerably and one species is unable to adapt. 2)
Another species in the food web becomes extinct. 3) Another
species that is either a carnivore, a predator, or a disease causing
organism is introduced into the ecosystem.
- Predator- Kills and feeds
off other living animals
- Lesson 5:The Nitrogen Cycle
- The atmosphere is 78% nitrogen gas (N2). This is
very unreactive, so it can't be used directly by
plants or animals. Nitrogen is needed to make
proteins, which are essential for growth. Animals
can get proteins from eating plants (or other
animals), but where do plants get proteins from?
Proteins are made up of units called amino acids,
and plants make amino acids. But plants need help
because they can't use nitrogen directly, they can
only use nitrates in the soil. Plants need certain
bacteria to turn nitrogen in the air into nitrogen
compounds (e.g. nitrates), so that they can absorb
them and use them to make amino acids.
- There are three special groups of bacteria
- 1) Nitrogen-fixing bacteria- They take
nitrogen gas and make nitrites or
ammonium compounds
- These either live 'free' in the soil or in
swellings in the roots of certain plants,
such as legumes (e.g. peas, beans, clover,
vetch) which have pods for fruit.
- The bacteria and the plant living
together is called symbiosis or
mutualism. Both benefit from each
other, as the plant gets nitrates and the
bacteria gets 'food' (glucose) and
protection.
- The bacteria and the plant living
together is called symbiosis or
mutualism. Both benefit from each
other, as the plant gets nitrates and the
bacteria gets 'food' (glucose) and
protection.
- These either live 'free' in the soil or in
swellings in the roots of certain plants,
such as legumes (e.g. peas, beans, clover,
vetch) which have pods for fruit.
- 2) Nitrifying bacteria- convert nitrites and
ammonium compounds into nitrates
- 3) Denitrifying bacteria- remove nitrogen
as gas to release back into the air (recycle)
- 1) Nitrogen-fixing bacteria- They take
nitrogen gas and make nitrites or
ammonium compounds
- There are three special groups of bacteria
- Non Living Nitrate Manufacture:
You can make nitrates chemically-
inorganic fertilisers (NPK).
Lightning- energy combines
nitrogen and oxygen in the air,
which makes nitrates.
- The atmosphere is 78% nitrogen gas (N2). This is
very unreactive, so it can't be used directly by
plants or animals. Nitrogen is needed to make
proteins, which are essential for growth. Animals
can get proteins from eating plants (or other
animals), but where do plants get proteins from?
Proteins are made up of units called amino acids,
and plants make amino acids. But plants need help
because they can't use nitrogen directly, they can
only use nitrates in the soil. Plants need certain
bacteria to turn nitrogen in the air into nitrogen
compounds (e.g. nitrates), so that they can absorb
them and use them to make amino acids.
- Lesson 4: Photosynthesis, Respiration
and the Carbon Cycle
- Photosyntheis
- Carbon Dioxide + Water--------(light)--------> Oxygen + Glucose
- 6CO + 6H O-----------(Chlorophil)------> 6O + C H O
- Plants only do this in the light (Day time).
- Carbon Dioxide + Water--------(light)--------> Oxygen + Glucose
- Respiration
- Oxygen + Glucose -------------> Carbon Dioxide + Water
- 6O + C H O --------------> 6CO + 6H O
- Plants do this all the time (Day and Night).
- Oxygen + Glucose -------------> Carbon Dioxide + Water
- Photosyntheis
- Lesson 3: Energy
Transfers
- Most light energy from the sun is not used in photosynthesis- it is wasted.
Energy is lost as heat during reparation (plants and animals). Only about 10% of
the available energy (in biomass- chemical) is transferred to the next level. The
losses are mainly because organisms do not eat all the biomass and organisms
produce faeces (chemicals from biomass) and urine.
- In energy transfer flow charts, to find the amount
of energy transferred to the next level, you must
take away; Energy lost as heat, Energy lost in
faeces and Energy lost through uneaten material,
from the total energy transferred to that level.
- To find energy used for growth, take away Energy lost as
heat, and Energy lost in faeces from the amount of energy
transferred to that level.
- To find energy used for growth, take away Energy lost as
heat, and Energy lost in faeces from the amount of energy
transferred to that level.
- Most light energy from the sun is not used in photosynthesis- it is wasted.
Energy is lost as heat during reparation (plants and animals). Only about 10% of
the available energy (in biomass- chemical) is transferred to the next level. The
losses are mainly because organisms do not eat all the biomass and organisms
produce faeces (chemicals from biomass) and urine.
- Lesson 6: Measuring
Environemental Change
- Living Indicators: These are organisms that monitor
their environment and react to it. E.g. Some organisms
can only live in non-polluted (high oxygen)
environments. Examples of pollution include low
oxygen in water, high carbon dioxide in air, particulates
in air (soot, dust), excess nitrates, phosphates in water
and toxic waste.
- Mayfly larvae live in unpolluted water
(low nitrates), so if they don't survive in
a certain area of water, then it indicates
that it is polluted.
- Bloodworms only live in low oxygen water, so
if they are found in an area of water it
indicates that there isn't much oxygen present.
- Lichen are fungi and alga (protoctista).
Some types are very sensitive to levels of
sulphur dioxide in the atmosphere. The
number and type of lichen in a particular
area indicate how clean the air is.
- Mayfly larvae live in unpolluted water
(low nitrates), so if they don't survive in
a certain area of water, then it indicates
that it is polluted.
- Non-living Indicators: Chemical test (kits)
can be used to measure environmental
change. E.g. temperature, tests for
nitrates in water, and carbon dioxide
monitors- environmental monitoring.
- Living Indicators: These are organisms that monitor
their environment and react to it. E.g. Some organisms
can only live in non-polluted (high oxygen)
environments. Examples of pollution include low
oxygen in water, high carbon dioxide in air, particulates
in air (soot, dust), excess nitrates, phosphates in water
and toxic waste.
- Lesson 7: Evolution
- Life has existed on Earth for about 3500 million years. All the
species that have ever existed have evolved from these
original species. Over time, some organisms have continued to
evolve and survive whilst others have become extinct and died
out. Evidence for all of the changes comes largely from fossils,
and also more recently from analysing the chemical DNA (from
both living organisms and preserved extinct specimens). This recent
- Life first existed on Earth about 3500 million years ago. All the species that have ever existed have
evolved from these original species. Over time, some organisms have continued to evolve and
survive whilst others have become extinct and died out. Evidence for all of the changes comes largely
from fossils, and also more recently from analysing chemical DNA (from both living organisms and
preserved extinct specimens). This recent evidence has enabled scientists to work out where
different species fit on the Evolutionary tree and so determine how closely species are related to
each other.
- Life has existed on Earth for about 3500 million years. All the
species that have ever existed have evolved from these
original species. Over time, some organisms have continued to
evolve and survive whilst others have become extinct and died
out. Evidence for all of the changes comes largely from fossils,
and also more recently from analysing the chemical DNA (from
both living organisms and preserved extinct specimens). This recent
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