- vestigial structures
- similarities between embryos of different organisms
- the same DNA and RNA materials found in all organisms
- similar genomes found in almost all organisms.
Check Your Understanding
- Where did Charles Darwin collect evidence of evolution and what kinds of evidence
did he find? - What is natural selection?
- What kinds of traits change through evolution?
Introduction
Though the idea of evolution had been proposed prior to Charles Darwin, most people
think of Darwin’s name when they think of evolution. Unlike others before him who based
their ideas on speculation, opinions, myths, or folklore, Darwin’s theories were based on a
tremendous amount of scientific evidence.
In 1859, Charles Darwin and Alfred Russel Wallace first presented several forms of evidence
of evolution. Their evidence included:
- fossils of extinct species from different eras
- similarities between the embryos of different species
- physical traits of different species
- the behavior of different species
- the distributions of different plant and animal species around the world.
Darwin and other 19thcentury scientists came to the conclusions they did without knowing
anything about molecular biology. Today, even more evidence of evolution by natural se-
lection is coming from molecular biology and genetics. Genetics is also helping explain the
mechanisms of how evolution occurs.
The Fossil Record
Paleontologistsare the scientists who study fossils to learn about life in the past.Fossils
are the preserved remains or traces of animals, plants, and other organisms from the distant
past. Examples of fossils include bones, teeth, impressions, and leaves. Paleontologists
compare the features of species from different periods in history. With this information,
they try to unravel how species have evolved over millions of years (Figure 26.2). This