Transcript Evolution and electricity - the Primary National Curriculum 2014

PRIMARY SCIENCE
Education Consultancy
Evolution and inheritance
Led by Naomi Hiscock
[email protected]
www.primary-science.co.uk
Starting question
• Why are there 17 different varieties of
penguins?
• Over 400 types of dogs?
• Why are there no woolly mammoths
anymore?
Variation
• It all starts with variation.
Adaptation
Living things are adapted (suited) to their
environments – their structure, how they
function and their behaviour are all suitable
to help them survive in their usual
environments.
• Birds have wings, fish have fins
• Cheetahs run very fast, moles dig quickly
• Hedgehogs roll into a ball
A hostile environment
• In an ashtray
• On a shower curtain
• In a wallet
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What key obstacles will it need to overcome?
What will it eat?
How will it stay safe?
How will it reproduce?
How will it colonise new places?
Plant adaptation
• Plants are also adapted to their
environment, though the adaptations are
often less obvious
– Cactus
– Nettles
– Water lillies
– Bluebell
How did they become adapted?
Possible answers:
1. God made them like that – a giraffe was given a long
neck so that it can reach the leaves at the top of the
trees
2. Living things change to suit their environment – giraffes
constantly stretch their necks to reach the leaves at the
top of the trees, so during their lifetime their necks
gradually get longer (Lamarck)
3. Individual giraffes don’t change, but the average neck
length in a population gets longer (Darwin)
Thinking about evidence
1. God made them like that – a giraffe was given a long
neck so that it can reach the leaves at the top of the trees
No evidence to support or refute
2. Living things change to suit their environment – giraffes
constantly stretch their necks to reach the leaves at the top
of the trees, so during their lifetime their necks gradually
get longer (Lamarck)
Lots of evidence to refute
3. Individual giraffes don’t change, but the average neck
length in a population gets longer (Darwin)
Massive amounts of evidence to support
How does evolution happen?
A simplified explanation
• Individuals in a population show natural variation
• If the environment changes – or if an organisms
behaviour changes – then different organisms
will be better adapted to the environment
• The organisms that are better adapted will
survive better, so the population gradually
changes over a long period of time.
Cockroaches
Cockroaches used to be caught and killed
by being lured into traps with sugary bait
and then sprayed with poisonous
insecticide. Cockroaches that possessed the
gene that interprets ‘sweet’ tastes as bitter
avoided the bait and were not exterminated.
Wink murder
How does evolution happen?
• In any population organisms vary because of
sexual reproduction and mutations
• There is always a struggle for survival
• Natural selection of the best-adapted organisms
(Darwin called this ‘Survival of the fittest’)
• Offspring resemble their parents because the
parents’ genetic material is passed on
• The population gradually changes (evolves)
• The population becomes better adapted to its
environment over a long period of time
Interactions
Organisms interact with their environment.
They may evolve to suit their environment
• Peppered moths during the Industrial
Revolution
Interactions
Some organisms can change their
environment through their interactions
• Plants growing on sand dunes
Interactions
• Organisms also interact with each other.
They evolve in a certain way because of
each other
Selective breeding
• People selectively breed domesticated
plants and animals to produce offspring
with preferred characteristics.
• Artificial selection provides a model for
natural selection
Selective breeding in dogs
• Dogs are part of a single species, Canis
familiaris.
• There are over 400 different breeds of dogs.
• A breed is a subspecies. It takes many
generations to get a new breed.
• Many breeds today are a result of artificial
selection/selective breeding.
American foxhound
• 400 years ago the American foxhound did
not exist.
Dog breeding example
• You want a dog that can hear a polar bear
approaching and alarm the bear so that it
will turn back.
• Which traits are important?
• Which are not important?
• Which two dogs would you breed?
Handout 1
Breeding your puppies
• Read the assignment (Ownership card)
• Decide what traits you desire
• Select which two dogs you will breed (Dog
breeds card)
• Which will be the male and which the female?
• You will breed three puppies
• Flip a coin for each trait for each puppy
– Heads - male trait, tails - female trait
• Record your puppies’ traits (Puppy traits card)
Preservation
‘Preservation’ results in the whole
organism being preserved as if it
had just dropped there. This
means that you can see many of
the tissues that the organism was
made of, such as skin or flowers.
This happens when the organism
falls into somewhere where there
is no oxygen, such as a tar pit or
resin which is fossilised to form
amber.
Evidence of evolution in fossils
• http://www.planetscience.com/categories/under-11s/ourworld/2011/10/what-makes-fossils.aspx
• Be a palaeontologist – chocolate chip and
tooth pick excavation
• Making fossils
• http://www.wikihow.com/Make-a-FossilOut-of-a-Sponge
Archaeopteryx
• Archaeopteryx lived 147 million years ago at the
end of the Jurassic Period. The fossils of this
extinct animal provide conclusive proof that birds
evolved from dinosaurs.
• They are probably the most famous transitional
fossils, showing a combination of dinosaur
and bird characteristics that prove modern
birds evolved from small meat-eating dinosaurs.
Dinosaur features
The skeleton of Archaeopteryx is essentially that of a small meat-eating
dinosaur (theropod) such as Deinonychus and Velociraptor.
Dinosaur characteristics include:
• a lightly-built skeleton
• very long arms
• a half-moon-shaped bone
in the wrist
• a long bony tail
• long legs
Bird features
Archaeopteryx also had features typical of birds, such as:
• aerodynamic flight feathers with an asymmetric vane
• wings with a flight feather arrangement just like modern birds
• a reversed ‘perching’ toe on the hind foot
Using CT scanning they have also
discovered that Archaeopteryx had:
• a bird-like brain with large areas that
co-ordinated flight, balance and sight
• semi-circular canals in the inner ear
that were the same size and shape
as in modern birds, suggesting
that Archaeopteryx had a sense of
balance comparable to modern birds
Useful website
www.nhm.ac.uk/nature-online/earth/fossils
The Natural History Museum as always has some great ideas and activities
and you can also get them in to do workshops for you.
www.discoveringfossils.co.uk/whatisafossil.htm
This website has some lovely illustrations to really show how a fossil is formed,
although it is more geared up to getting you involved in fossils and running
days to do this. A good ‘dip in’.
http://beyondpenguins.ehe.osu.edu/stories-for-students
This website has some great stories about the south and north pole
www.sheppardsoftware.com/scienceforkids/dinosaurs/
fossils.htm
Possibly one for the children to use directly.
Exploration
• Can you make the bulb light?
• Use all the resources
• What is the least number of resources you
need?
• What does this additional component do?
Electricity: Year 4
• identify common appliances that run on electricity
• construct a simple series electrical circuit, identifying
and naming its basic parts, including cells, wires, bulbs,
switches and buzzers
• identify whether or not a lamp will light in a simple
series circuit, based on whether or not the lamp is part
of a complete loop with a battery
• recognise that a switch opens and closes a circuit and
associate this with whether or not a lamp lights in a
simple series circuit
• recognise some common conductors and insulators,
and associate metals with being good conductors
Making a circuit work
Help the children to establish the following
three points
1. That a cell (battery) is required
2. That the circuit must be unbroken
3. That all the components have two ‘ends’
or ‘places for connections’ (terminals) and
that both of these must be in the loop
Teaching tips
• Teach the children to problem solve
systematically if something appears to not
be working
• Only give children one component at a
time
• Give them experience of using cells and
bulbs without the holders
Important things to know
• Cells and batteries (explicit vocabulary)
• Cells and bulbs do not need to be in holders
• The purpose of plastic coating on wires and crocodile
clips is not to stop us being electrocuted
• Cells need to be joined correctly (+ to -)
• Buzzers only work if connected the correct way to the
cell
• Bulbs have a limiting voltage. If it goes beyond this the
bulb blows (3.5V bulbs are fine with three cells)
Electricity: Year 6
Pupils should be taught
• associate the brightness of a lamp or the volume of a
buzzer with the number and voltage of cells used in
the circuit
• compare and give reasons for variations in how
components function, including the brightness of
bulbs, the loudness of buzzers and the on/off position
of switches
• use recognised symbols when representing a simple
circuit in a diagram.
Recording circuits
• Build a circuit and record it in a circuit
diagram
Changing circuits
• Can you make the motor spin faster and
slower?
• Can you make it spin in the opposite
direction?
• Can you think of a way to measure the
speed of the motor?
Taking it further
• Conductors and insulators – why do
metals conduct electricity and other
materials do not?
Current
• Current is a measure of how
much electric charge flows through a
circuit. The more charge that flows, the
bigger the current.
• Current is measured in units called amps.
The symbol for amps is A.
• Measure the current at different places in
circuits using the ammeter.
Voltage
• Voltage is a measure of the difference
in electrical energy between two parts of a
circuit. The bigger the difference in energy,
the bigger the voltage.
• Voltage is measured in volts. The symbol
for volts is V.
• Measure the voltage across different
components in circuits using the voltmeter.
Resistance
• The electrical resistance of an electrical
conductor is the opposition to the passage of an
electric current through that conductor
• It is measured in ohms. The symbol for ohms is
Ω
• It can be calculated by measuring the current
through it and voltage across is and using the
formula V = I x R
• I = current, V = voltage, R = resistance
Modelling circuits
• Modelling the cause and effect
• Modelling to support scientific
understanding
Making more advanced switches
• Can you make a switch to make a motor
change direction?
• Can you make a variable speed switch?
Making predictions
• Look at the circuits on the sheets.
• Predict whether they will work and the
brightness of each bulb.
• What would happen if the switches were
closed?
• Try out any circuits you were not sure of.