Chapter 16 Section 3 The Process of Speciation AZ State Science Standards S4C4PO1: Identify the following components of natural selection, which can lead to speciation: potential for a species to increase its numbers; genetic variability and inheritance of offspring due to mutation and recombination of genes; finite supply of resources required for life; selection by the environment of those offspring better able to survive and produce offspring S4C4PO2 Describe how the continuing operation of natural selection underlies a population’s ability to adapt to changes in the environment and leads to biodiversity and the origin of new species Objectives: -Identify the condition necessary for a new species to evolve -Describe the process of speciation in the Galapagos finches

Evolution of Corvette List three adaptations that have occurred and the pressures that may have caused these changes

Speciation: Changes that lead to the formation of new species Species- A group of organisms that breed with one another and produce fertile offspring (progeny)… which means they share a common gene pool

Isolating Mechanisms: In order for a species to evolve into a new species, the gene pools of two populations must become separated…they must become reproductively isolated from one another

Isolating Mechanisms Con’t: Behavioral Isolation: -Occurs when two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies For example: eastern vs western and songs that attract mateseastern western

Isolating Mechanisms Con’t: Geographic Isolation: – Occurs when barriers such as rivers, mountains, etc separate two populations – For example: Albert and Kaibab Squirrels are separated by the Grand Canyon

Isolating Mechanisms Con’t: Temporal Isolation: -Two or more species reproduce at different times For example: Three similar species of orchid release pollen on different days, thus they are unable to pollinate one another

Temporal Isolation

Darwin’s Finches Read pages What type of isolating mechanism was important in the formation of Galapagos finch species?