Natural Selection

and

The Evolution Game

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After successfully participating in this lab, you will be able to:Explain how predation affects reproduction.Explain how reproduction affects

evolutionary fitness.Describe factors that affect individual

survival.Demonstrate the difference between

individual and species survival.Estimate the evolutionary fitness of a species

by interpreting population data.

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What is Evolution?Evolution simply means change over time.

Evidence that life has evolved: Fossils, DNA, similarities in morphology of different species

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This does not mean that humans evolved from monkeys

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Genealogy of Dogs

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Extinct Hominids – look who survived

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For Natural Selection to occur:

1.) There must be variation in traits between individuals within a population

2.) The traits must be heritable.

3.) Certain variants of the trait must be more advantageous than others

4.) Those with the most advantageous variants are more likely to survive and reproduce (evolutionary fitness)

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For Natural Selection to occur:You cannot "will yourself" to get an

adaptation. The adaptations must naturally occur in populations.

For example, if a species of butterfly is orange, and a mutation occurs that makes a butterfly red, if red helps the organism survive, then it will be passed on to offspring.

Happens over millions of years, thousands of generations. The Earth is 4.6 billion years old –that's a long time for organisms to change.

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Charles Darwin

• Theory of Natural Selection•"those individuals who possess superior physical, behavioral, or other attributes are more likely to survive than those which are not so well endowed.“•In plain English – “Survival of the Fittest” means the most well adapted organisms will survive to reproduce.

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Darwin and the Galapagos IslandsDarwin compiled evidence for natural selection from decades of observations around the world. This is why it is referred to as the Theory of Natural Selection – not just a guess.

Most famous for studying tortoises and finches on the Galapagos Islands

600 miles from South America—ancestral species migrated to islands and adapted to many different island environments over millions of years

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Giant Galapagos Tortoises

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ADAPTATION

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Leaf, or Insect???Adaptation: Camouflage

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COEVOLUTIONYucca Moth and Yucca plant coevolved for pollination, a mutually beneficial relationship

Cheetah and Gazelle Coevolved for SPEED. One to outrun the other.

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The Peppered Moth

Prior to the industrial revolution, selection favored light-colored individuals; the dark phenotype was rare

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•Industrial Revolution (late 1800’s) = more soot and pollution•Sulfur dioxide emissions kill light-colored lichens. •No lichens = dark-colored environment favorable for dark-colored moths to blend into and avoid predation!•More dark-colored variants survive; today there are many more dark individuals!

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How many moths can you see?

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THE EVOLUTION GAMEObjectivesAfter successfully participating in this lab, you will be able to:• explain how predation affects reproduction.• explain how reproduction affects evolutionary fitness.• describe factors that affect individual survival.• demonstrate the difference between individual and speciessurvival.• estimate the evolutionary fitness of a species by interpretingpopulation data.

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Why do we play a game in lab?

SimulationTaking a class of 640 Natural

Science students out into the field to observe predator/prey interactions would be very expensive (to go to the Galapagos would be $10,000 each)

Predators/Prey never act like they do in nature when confined to lab

This game is fun and actually informative #NSB2014 22

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