Evolution
Key Word
Description
Example
variation
There is variation between individuals in a
population. Occasionally, new mutations
occur which give an advantage.
There was natural variation in
neck length between giraffes.
competition
The individuals in a population compete
for food, shelter and mates.
The giraffes competed for the
food that was available.
adaptation
Some adaptations make the individual
better at competing.
Giraffes with longer necks were
able to reach higher into the
trees so had more food available.
natural
selection
The individuals with the better
adaptations are more likely to survive
and reproduce.
These giraffes were more likely
to survive.
inheritance
When they reproduce, they pass on the
alleles for the useful adaptation.
They reproduced and passed on
the alleles for long necks to their
offspring.
time
Over many generations, the number of
individuals with the adaptation increases.
Over time, the population of
giraffes with long necks increased.
1. Use the information above to explain why elephants have evolved to have long trunks.
2. Come up with a way to record the six key words and descriptions above that will help you
to learn them. You may choose to make flashcards, draw a diagram, draw a flowchart
that shows each point or write a comic or story that shows the process of evolution
(highlighting the key words). Make sure it is something that you will be able to use to
revise for your exam.