What is Natural Selection? The Theory of Natural Selection explains how one species might be able to change into another The Controversy?! Evolution Species slow change over millions of years Descent with modification from a common ancestor Random *arguable Creation Intelligent Design (ID) Species show characteristics of design and intent Natural selection allowed genetic traits to emerge Not random Changing Populations Facts Involved Species DO change Adaptation Genotype Resistance to disease Immune systems adjusting to contagions/poison Competition for Breeding rights/mating Survivability - Food, fighting, etc Adaptation to Hunting Most African Elephant males grow tusks In the 1930s less than 1% of the male elephants were born tuskless Today 15% of male elephants are tuskless! Adaptation to Hunting cont Why the change in tuskless elephants? Before they were a protected species hunters hunted elephants for the ivory of their tusks With less elephants with tusks, the tuskless were able to breed more And therefore there are more elephants without tusks than there was before Insecticide Resistance When using insecticides most of the insects die (99%+) The 1% that does not die can pass this immunity on to the next generation Soon most of the insects will have this resistance Competition for Mates Breeding to guarantee the survival of the species When choosing mates, specific adaptations will be selected. Coloring Strength Stamina Forming New Species Facts Involved A species is a group of organisms that can mate and produce fertile offspring Speciation Speciation occurs when a group becomes separated from the original population & forms a new species with different characteristics, habits &/or diet The finches of the Galapagos Island is the most often used example. Forming New Species continued 3 basic steps toward Speciation 1 - Separation Separating from the parent group Due to environmental, geographical, or biological reasons 2 - Adaptation Adapting to a new environment Different foods? Predators? Climate? 3 - Division May become very different to the point of not being able to breed with the original species Mating times, size considerations, food preferences, etc. p.116 Separation Adaptation Further Separation More Specific Adaptation Division Darwins Finches - Natural Selection? Maybe or Maybe not Final words on Speciation Genus Many scientists view members of the same Genus to be genetically compatible species In other words - THEY CAN INTERBREED WITH EACH OTHER. Whether or not they do is the issue of speciation Wolves can breed with Coyotes, but dont. Why do you think?