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Edexcel Biology GCSE Topic 4 – Evolution and Natural
Selection
Evolution
Evolution is the slow and continuous change of a species’ inherited characteristics
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Antibiotic resistance
Antibiotic resistance is strong evidence for the theory of evolution
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This makes
them more likely to survive
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Charles Darwin
Charles Darwin published his theory of evolution in 1959, after he had travelled to the
Galapagos an found variations between the islands of the archipelago
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They ended up publishing papers on evolution
together, although they didn’t always agree
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She originated from Ethiopia
and is 4
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The structure of her feet indicates a tree climber, whilst her

figure was more similar to an ape than the modern human
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“Lucy” is the name given to a fossil of Australopithecus afarensis
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2 million years old
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Her body figure is in between that of an Ape and a Human
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The structure of Lucy’s legs is more
developed than Ardi, suggesting she walked more than Ardi
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6 million years old
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He has further developed leg structure, indicating
most of his time was spent walking rather than climbing
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The complexity of these tools
increases over time, indicating a development in brain size and capacity
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By the time of the Neanderthals, they
were using sharpened tools, such as spears and hunting tools
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In all modern animals with four
limbs, the pentadactyl limb is present in some form
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The 5 kingdom classification is more
traditionally used, but is older than the 3 domain classification
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Below this, there are Phyla, Classes, Orders, Families,
Genuses and Species
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The 3 domain classification splits all organisms into Eukarya, Archea and Bacteria
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Selective Breeding
Selective breeding is the process of selecting organisms with useful traits and breeding
them to make that trait prevalent
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The process is similar to natural selection, but only the organisms
with the useful characteristics are bred together, in order to speed up the process
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The issue with selective breeding is that it reduces the gene pool, increasing the risk of
harmful genetic defects
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Another issue is diseases,
which can harm a large proportion of the population due to the lack of variation
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This is mainly used
to produce plants
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This must be kept sterile
(aseptic)
4) As the tissues produce shoots and roots they can be planted like normal plants
Animal tissue culturing is used to grow specific cells, although we can’t grow full
animals yet
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Genetic Engineering (Higher tier only)
Genetic engineering is the process of transferring one organism’s gene to another
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The process is:
1) Remove the gene using a restriction enzyme
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The two pieces are joined using ligase, to form recombinant DNA
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5) Which now codes for the new protein

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