module 4.2 natural selection

module 4.2 natural selection

1. natural selection

   • the process in which an environmental factor acts on a population and results is some organisms having more offspring that can survive to reproduce than others.

2. selective agent

   • an environmental factor that acts on a population during natural selection
     • biotic
       • bacterial infection
       • competitor
       • predator
     • abiotic
       • temperature
       • water
       • soil nutrients
       • fire

3. selection pressure

   • the effect of a selective agent on a population

4. sexual selection

   • a special case of natural selection in which the environmental factor is the selection of a mate
     • species gradually becomes better adapted to its environment

5. variation

   • differences in characteristics due to different genes.

6. resistance

   • the inherited ability of a species to withstand chemicals such as pesticides

7. antibiotics

   • chemicals made by organisms to defend themselves against bacteria

8. speciation

   • biodiversity
     • the number and range of species that exist on earth or in an ecosystem
   • the process by which one species splits into two or more separate species
     • variation
     • isolation
       • keeping interbreeding groups apart by some barrier or mechanism.
     • selection