Biology Forums - Study Force

There are many examples and types of evidence for evolution.  You have been looking at fossils/transitional fossils, patterns of distribution/biogeography, anatomy, embryology, molecular biology and genetics.

1.   What type of evidence (what category) do you find the most compelling and why?

Do a little bit of independent research and give one good example of evidence for evolution that you find interesting.  You can start with something you initially found in your text or the online content, but you should then move on to material from other sources (cite your sources!) to further support and explain your example.

2.   What is your example of evidence for evolution?  Explain and support your example.

3.   What is it that you find most interesting/compelling about the example you chose?

- The fossil record of change in earlier species
- Chemical and anatomical similarities of related life forms
- Geographic distribution of related species
- Genetic of living things over generations

1.Cellular/Molecular Evidence

2. All living things are fundamentally alike. At the cellular and molecular level living things are remarkably similar to each other. These fundamental similarities are most easily explained by evolutionary theory: life shares a common ancestor.

The cellular level

All organisms are made of cells, which consist of membranes filled with water containing genetic material, proteins, lipids, carbohydrates, salts and other substances. The cells of most living things use sugar for fuel while producing proteins as building blocks and messengers. Notice the similarity between the typical animal and plant cells pictured below — only three structures are unique to one or the other.

The molecular level

Different species share genetic homologies as well as anatomical ones. Roundworms, for example, share 25% of their genes with humans. These genes are slightly different in each species, but their striking similarites nevertheless reveal their common ancestry. In fact, the DNA code itself is a homology that links all life on Earth to a common ancestor. DNA and RNA possess a simple four-base code that provides the recipe for all living things. In some cases, if we were to transfer genetic material from the cell of one living thing to the cell of another, the recipient would follow the new instructions as if they were its own.

3. These characteristics of life demonstrate the fundamental sameness of all living things on Earth and serve as the basis of today's efforts at genetic engineering. They can give us more accurate relationships, as genes are more specific to all living beings.