Patterns of Evolution

• What does "Patterns of Evolution" refer to?

  Observable trends in species change over time
• What is co-evolution?

  When closely interacting species exert selective pressures on each other
• How does predator-prey interaction illustrate reciprocal selection?

  Predators evolve better hunting traits, prey evolve defenses
• How do plants and pollinators co-evolve?

  Plants provide nectar, pollinators assist in reproduction
• What is divergent evolution?

  When traits from a common ancestor evolve into variations
• What is convergent evolution?

  Similar adaptations arise in different species due to similar pressures
• Why do sharks and dolphins have similar traits despite being unrelated?

  Similar selective pressures in the ocean environment
• What is an example of divergent evolution?

  The evolution of vertebrate limbs
• What is the Bottleneck Effect?

  Genetic drift from population reduction
• How does a bottleneck affect genetic variation?

  It reduces genetic variation in the population
• What is a consequence of decreased genetic variation?

  Increased differences between populations
• Why are small populations more susceptible to environmental impacts?

  They have less genetic variability
• What is coevolution?

  Species exert selective pressures on each other
• What is divergent evolution?

  Adaptation to new habitats causing diversification
• What are homologous structures?

  Structures with a common evolutionary origin
• What is a consequence of divergent evolution?

  Speciation into two or more species
• What is gradualism in evolution?

  Evolution occurs slowly over millions of years
• How does gradualism affect population change?

  Small variations are selected for over time
• What happens to individuals with helpful traits in gradualism?

  They survive and reproduce more successfully
• What is the main difference between gradualism and punctuated equilibrium?

  Gradualism is slow, while punctuated equilibrium is rapid
• What characterizes punctuated equilibrium?

  Change occurs in spurts after long periods of stability
• What can cause punctuated equilibrium to occur?

  Mutations or sudden environmental changes
• How does punctuated equilibrium relate to mass extinctions?

  It often follows mass extinctions creating new niches