Ch. 10.4 : Evidence for Evolution Flashcards
Describe how different scientists contributed to the theory of evolution
Lyell - suggested that fossils were actually evidence of animals that had lived millions of years ago
Hutton - proposed theory of uniformitarianism ( the idea that the earth was shaped by natural processes we can still see today )
Darwin - came up with the theory of evolution by natural selection through observations in Galápagos Islands / jointly
published theory.
Wallace - came up with theory of evolution by natural selection in Borneo / jointly published theory.
What are the sources scientists use to study the process of evolution?
Palaeontology - the study of fossils and the fossil record
Comparative anatomy - the study of similarities and differences between organisms anatomy
Comparative biochemistry - similarities and differences between the chemical makeup of organisms
What is the evidence for evolution given by the fossil record?
Fossils of the simplest organisms such as bacteria and simple algae are found in the oldest rocks. Fossils of more complex organisms such as vertebrates are found in more recent rocks. This supports the theory that simple life forms gradually evolved to be more complex over a long period of time.
The sequence in which the organisms are found matches their ecological links to each other. For example, plant fossils appear before animal fossils. This is consistent with the fact that animals require plants to survive.
By studying similarities in the anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestor.
Fossils allow relationships between extinct and living organisms to be investigated
What is the evidence for evolution given by comparative anatomy?
As the fossil record is incomplete, scientists use comparative anatomy.
A homologous structure is a structure that appears superficially different ( and may perform different functions ) in different organisms, but has the same underlying structure.
The presence of homologous structures provides evidence for divergent evolution. This describes how different species have evolved from a common ancestor, each with a different set of adaptive features.
What is the evidence for evolution given by comparative biochemistry?
Changes in highly conserved molecules can help identify evolutionary links such as chromosome C and ribosomal RNA. Species that are closely related have the most similar DNA and proteins. Distantly related species have far fewer similarities.
What are the disadvantages of using the fossil record as evidence for evolution?
Many organisms decompose before they have a chance to fossilise
Some are destroyed by volcanoes or earthquakes
Therefore it is incomplete
