History of Biological Diversity Evolution: Darwin’s travel

Developing the Theory of Evolution The Galápagos Islands Darwin noticed that the different islands all seemed to have their own, slightly different varieties of animals. Somewhat similar species that suited their particular environment. Copyright © McGraw-Hill Education In 1859 On the Origin of Species presented evidence and proposed a mechanism for evolution that he called natural selection.

Natural Selection is Survival of the fittest Natural selection is a process of elimination ORGANISMS THAT HAVE TRAITS THAT ARE BEST ADAPTED FOR THE CURRENT ENVIRONMENT ARE THE ONES THAT SURVIVE TO BREED AND PASS ON THEIR GENES TO THE NEXT GENERATION, CAUSING A CHANGE IN THE OVERALL POPULATION. Organisms not possessing the beneficial traits either die or don’t have as many offspring. Natural Selection is Survival of the fittest Biological fitness- ability of an organism to survive AND reproduce (pass on its genes)

Main Points of Natural Selection Genetic Variation is present in the population and it is inherited (passed to offspring) -Mutations: Changes in the DNA -Meiosis: crossing over -Random mate selection & fertilization Living Things Overproduce Offspring (not all survive) Competition for Limited Resources Survival of the “Fittest”

Natural Selection Fitness Differential Reproductive Success Genetic Limited Resources Organisms produce more offspring than can survive. Environmental Factors Differential Reproductive Success Natural Selection Fitness Competition Genetic Variation Differential reproduction is the idea that those organisms best adapted to a given environment will be most likely to survive to reproductive age and have offspring of their own Make sure students know the definitions to the following terms: genetic variation, fitness, competition, resources, and environmental factors. Take time to explain how the various components lead to DRS.

Adaptations-a change or the process of change by which an organism or species becomes better suited to its environment. Types of adaptations Camouflage is a suite of morphological adaptations that allow an organism to blend into its environment. Mimicry is a type of morphological adaptation where a species evolves to resemble another species. Antibiotic resistance develops in some bacteria,making them able to survive antibiotic treatments Mimicry Camouflage