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What would
happen if…
…this polar bear
was bright pink?
…this cactus didn’t
have spikes?
…this camel didn’t
have a hump?
Adaptations
Species are adapted to suit their environment
Those that are not well adapted to their surroundings will
die.
Those that are well adapted will survive and reproduce
Adaptations are passed on to the next generation
This is survival of the fittest
Evolution…
A gradual change in
characteristics of a
plant or an animal
over time
The giraffe – Evolution by natural
selection - Charles Darwin
Once upon a time…
Giraffes once had variation in neck lengths
Giraffes compete to eat leaves from the trees and
bushes
Over time the leaves start to thin out on the lower
branches…
…to the point where the short-necked giraffes can no
longer reach
The short-necked giraffes can no longer eat so die
The long-necked giraffes survive and reproduce to
pass on their genes
The population of giraffes all have long necks.
They have adapted to their environment
Your task
Complete the comic strip to describe how giraffes evolved
by natural selection (diagrams and descriptions)
Try to use the following key words
- Natural selection
- Variation
- Competition
- Genes
- Survive
- Reproduce
- Adaptation
Natural selection - Giraffe
Your experiment
Investigate Darwin’s theory on finches.
Use different types of ‘beaks’ to pick up the food.
How much food does each type of beak pick up in 1 min?
You can only pick up one bead at a time.
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You will be in groups of 3
Each person will have a different shape ‘beak’
Each person has to pick up as many bits of food as possible in 1 min
Record the amount of food each beak picked up
Repeat the experiment 3x
Take an average of the results
Draw a graph to show and compare results
Write conclusion about results
Beak
Tweezers
Tongs
Spoon
1
2
3
Average
Exam question (5 marks)
Natural selection is one of the theories of
evolution. State the person whose theory it is,
and how it occurs using an example.
Exam question
1 mark:
(Charles) Darwin
4 marks from the following:
Giraffe population has variation in neck length
Giraffes with short necks cannot reach branches
Giraffes with short necks die
Giraffes with long necks survive
Giraffes with long necks reproduce
Gene for characteristic of long neck passed on to next
generation
Mimic…
Copying
Mimicry
Can be copying the surroundings
Can be copying other animals
Why would they do that?
Copying surroundings
Copying other animals
Now find the animals in the
following pictures…
E.g. This is a stick insect
You now have to find him!
FIND THE FOX
WHAT IS HIDING HERE?
Which animals mimic?
On your tables create a list of animals that
either
1. Mimic their surroundings
2. Mimic other animals
Surroundings
Other animals