1.5 Natural Selection

• Adaptive radiation


  An evolutionary pattern in which many species evolve from a single ancestral species
• Hybrid


  The offspring of two parents of different species.
• Reproductive isolation


  Separation of species or populations so that they cannot interbreed and produce fertile offspring
• Geographical isolation


  form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water
• Sympatric speciation


  The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present.
• Allopatric speciation


  The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.
• Speciation


  Formation of new species
• MRSA

  Methicillin-Resistant Staphylococcus Aureus; an infectious disease caused by a pathogen that is resistant to many antibiotics
• Resistance


  When bacteria are no longer affected by antibiotics
• Selection pressure

  A change in environment or circumstances that favours one form of organism or species over another.
• Behavioural adaptation


  any behaviour of an organism that allows it to better survive and reproduce in an environment (e.g., migration)
• Physiological adaptation


  a physical or chemical event that occurs within the body of an organism and enables survival
• Anatomical adaptation


  An adaptation that has to do with an organism's physical structure
• Ecological niche


  A specific role of a species within an ecosystem, including its use of resources, and relationships with other species.
• Phenotype


  An organism's physical appearance, or visible traits.
• Ecology


  Scientific study of interactions among organisms and between organisms and their environment
• Gene pool


  Combined genetic information of all the members of a particular population
• Allele


  Different forms of a gene
• Genotype


  Genetic makeup of an organism
• Natural selection


  Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest