What is Natural Selection?
20
What is Natural Selection? The Theory of Natural Selection explains how one species might be able to change into another
description
What is Natural Selection?. The Theory of Natural Selection explains how one species might be able to change into another. Evolution Species slow change over millions of years Descent with modification from a common ancestor Random *arguable. Creation Intelligent Design (ID) - PowerPoint PPT Presentation
Transcript of What is Natural Selection?
What is Natural Selection?
The Theory of Natural Selection explains how one species might be
able to change into another
The Controversy?!
EvolutionSpecies slow change over millions of years Descent with modification from a common ancestorRandom *arguable
CreationIntelligent Design (ID)
Species show characteristics of design and intentNatural selection allowed genetic traits to emerge Not random
Changing PopulationsFacts Involved…
Species DO changeAdaptation
Genotype Resistance to disease
Immune systems adjusting to contagions/poisonCompetition for …
Breeding rights/matingSurvivability - Food, fighting, etc…
Adaptation to Hunting
Most African Elephant males grow tusksIn the 1930’s 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 tusksWith less elephants with tusks, the tuskless were able to breed moreAnd therefore there are more elephants without tusks than there was before
Insecticide ResistanceWhen using insecticides most of the insects die (99%+)The 1% that does not die can pass this immunity on to the next generationSoon most of the insects will have this resistance
Competition for MatesBreeding to guarantee the survival of the species When choosing mates, specific adaptations will be selected.
ColoringStrengthStamina
Forming New SpeciesFacts Involved…
A species is a group of organisms that can mate and produce fertile offspringSpeciation occurs when a group becomes separated from the original population & forms a new species with different characteristics, habits &/or dietThe finches of the Galapagos Island is the most often used example.
Forming New Speciescontinued…3 basic steps toward Speciation
1 - SeparationSeparating from the “parent” group
Due to environmental, geographical, or biological reasons
2 - AdaptationAdapting to a new environment
Different foods? Predators? Climate?
3 - DivisionMay 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
Darwin’s Finches - Natural Selection? Maybe or Maybe not
Final words on Speciation…
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 don’t. Why do you think?
