Through the study of fossils, scientists have been able to construct a geological timescale showing the stages of life that have been preserved over time. By radioisotope dating shells found in sedimentary rock, scientists can determine that some species existed 30 million years ago before similar but different shells. The similarities between structures like hands and wings show that animals evolved from common ancestors. During embryonic development, organisms proceed through stages that outline their evolutionary history. Biogeography has demonstrated that isolated populations evolve new traits suited to their environments over time. Comparing genetic codes, scientists have found nearly all organisms share the same basic code, indicating they evolved from a common origin.

1. Fossil Evidence
Through Palaeontology, evidence of evolution has
been clearly shown. The ages of the fossils can be
determined, so geologists have been able to construct
a “Geological Time Scale”, stating all of the stages of
life that have been preserved throughout time.
As an example, a sedimentary rock is found and
there, inside, is a perfectly preserved shell. After
radioisotope-dating, the shell is estimated to be 30
million years old, scientists are able to determine that
this specie was around before another type of shell,
that looks very similar...
Kate B

2. Anatomical Evidence
The evidence that all animals have come
from similar ancestors. Through the study of
all different animals, scientists have noticed
the similarities between, for example, human
hands and bat wings. Animals have changed
their structures to better suit their
environment, changing over time.
Kate B

3. Embryological Evidence
One biologist, Ernst Haeckel, proposed that
the embryo’s development outlined the entire
evolutionary history.
For example, a shark embryo begins as a
small, non-complicated being, then proceeds to a
tadpole looking thing, to a small fish being to the
shark itself. This can also be said of a chicken
embryo, a lizard embryo, a human embryo etc...
The younger embryos are all very similar, but as
they progress – evolve – they change until they
no longer look alike.
Kate B

4. Distribution Evidence
Biogeography – the study of the distribution of
plants or animals – has shown that animals on an
island, after being separated from the mainland, will
evolve to suit their new environment. The animals,
while of the same species, have new aspects and
characteristics best suited to the habitat.
Three hundred years ago, a flood separated off an
island. The lizards on the island now have to survive on
an island that has a wetter winter. For camouflage in
the swampy areas, the lizards become a dark green
rather than brown and yellow flecks, like on the
mainland.
Kate B

5. Genetics Evidence
From studying the structure of the genetic code,
scientists have been able to find that almost all
organisms have the same basic code. This shows that
all animals have a common ancestor and have evolved
to different species to suit the environment they are in.
The DNA of animals is reproduced as a code of four
letters – G, A, T and C. A goldfish has, approximately,
98% similarities of their code to humans. The two
animals are very different, but the genetic code
explains that, a extremely long time ago, life started
with a basic organism and evolved from there.
Kate B