Evidence and Patterns of Evolution

Stinging ants and the bull-thorn acacia plant are an example of this. 

Catastrophic events on a global level, like the ice age cause many species to go extinct. 

The proces in which one ancestral species diversifies into many descendent species. 

Crabs and Murex snails are an example of this. 

Process in which unrelated species evolve similar traits while adapting to similar environments

This type of structure is evidence for divergent evolution. 

2 or more species evolve in a cooperative way, evolving characteristics that help one another.

Process in which two species evolve in response to changes in each other, over many generations

This type of structure DOES NOT provide evidence of a common ancestor. 

2 or more species evolve in a competitive way in this type of coevolution. 

How many mass extinctions have taken place on Earth?

The image below demonstrates this type of structure.

Convergent evolution produces these types of structures. 

This is the cause of the current mass extinction. 

Brief episodes of speciation are followed by long periods of little evolutionary change.

The image below is an example of this type of structure.

Local changes in the environment, like food supply cause a few species to go extinct. 

Process in which closely related species become more diff. as they adapt to diff. environments.

This is a remnant of an organ or structure that had a function in an early ancestor.

The study of this provides evidence of a common ancestor.