8.3 Evolution as an Ongoing Process

• Co-evolution: The process in which one species evolves in response to changes in another species
• Mutualism: a symbiotic relationship

  wherein both organisms benefit from

  the interaction
• Many plants have evolved defense

  mechanisms in order to reduce

  herbivory
• Natural selection enabled some

  insects to adapt to poisons and

  benefit from them, allowing the

  insects to also become poisonous to

  their predators
• Mimicry: One species (mimic) evolves to resemble another (model) – may or may not be closely related species
• Batesian: harmless species evolves to mimic a harmful species
• Mullerian: two harmful species mimic each other(additional warning signs)
• Cumulative selection: The evolution of a simple structure into something more complex through a number of small adaptations.
• As the environment changes, specialized structures can adapt to new functions
• In terrestrial arthropods such as scorpions, the exoskeleton also helps prevent water loss and provides

  support to the body