Evidence of evolution

Direct observations of evolutionary change Natural selection in response to an introduced species: The evolution of Drug resistant bacteria Soapberry bugs balloon vines/goldenrain tree fruit pg 471 Staphylococcus aureus MRSA pg 472

Homology The study of similarities resulting from similar ancestry is known as homology. Homologous structures- Structures that have been shared be related species and have been inherited from a common ancestor. Some homologous structures can be similar in morphology, but very different in functionality. Vestigial Structures: Structures that are inherited from our ancestors, but no longer serve a purpose.

Comparative Anatomy of Homologous Structures in Chordates

Vestigial Structures and “remnant” DNA To maintain a structure in your body, you must constantly expend resources (The area is typically vascularize, innervated, and constantly using ATP) During the evolutionary process, structures that function purposefully in one organism will no longer function in another, as the environment no longer requires the need for that structure.

Vestigial structures showing how remnant DNA from a common ancestor still surfaces

Phylogenetic trees Also called an evolutionary tree , it is a diagram that reflects evolutionary relationships amongst organisms. Pg 474

How To Read a Phylogenetic Tree

Chordate phylogenetic tree

Convergent Evolution and Analogous Structures Convergent evolution is the independent evolution of similar features in different lineages. When an evolutionary path causes two organisms to develop similar traits despite having different ancestors. Structures that are very physiologically different, yet share the same function are called analogous structures. Example: sugar glider; flying squirrel

The Fossil Record Another form of supporting evidence for evolution comes from the fossil record. The fossil record can show the patterns of how certain organisms arose. This evidence is further supported by DNA evidence.

Biogeography, Pangaea, and Continental Drift Biogeography- The patterns in the distribution of life. Patterns and distribution of living and fossil species tell us how modern organisms evolved from their ancestors. This supports the theory that at some point the continents were connected to each other in the form of a super structure called Pangaea. Further, DNA technology can link endemic species to extinct species. Linking these endemic species on one continent to extinct species on other continents shows how at some point the continents moved to a new location through a process called continental drift. Example: glossopteris Earth: Permian era (298-252 mya)