ENVIRONMENTAL IMPACT OVER TIME Chapter 2 Section 3

 What types of factors can affect the survival of a species?  Nonliving Influences  Temperature  Rainfall  Pollution  Fire  Elevation  Volcanic eruption  Flooding

 Living Influences  Predators  Competition for food  Competition for territory

 Who are Charles Darwin and Alfred Wallace?  British biologists  Hypothesizing about how so many living things came to exist on Earth

 What was their hypothesis?  Different, long-term, environmental influences on populations produced the variety of species  Changes happen from generation to generation

 What did Darwin and Wallace call this process?  Evolution—the change in the genetics of a species over time.  Theory to explain how, over time, factors can act together and result in a new species.

 How does evolution happen?  Natural Selection— organisms that are better adapted to an environment survive and reproduce at a greater rate than organisms that are not  Can produce new organisms or new species

 What are other ways that species can change?  Mutation  Changes that occur to DNA  Favorable mutations— new species  Harmful mutations— stop reproduction or death to organism

 Selective Breeding  People select animals with desirable traits for breeding  Ex: Labradoodle

 Adaptive Radiation  Production of several species from one ancestral species  Occurs when environment favors more than one variation  Ex: Darwin’s finches

 What are two reasons for extinction?  Habitats are destroyed  New species are introduced that crowd out or prey on existing species