What is Evolution?What is Evolution?

Chapter 4.1 and 4.4Chapter 4.1 and 4.4

What conditions in the environment cause What conditions in the environment cause these 2 examples to survive and develop over these 2 examples to survive and develop over

thousands of years?thousands of years?

Locate the animalLocate the animal

Locate the animalLocate the animal

Locate the animalLocate the animal

EvolutionEvolution GenesGenes control the inherited control the inherited traitstraits of organisms. of organisms.

Evolution can only occur when the Evolution can only occur when the gene poolgene pool of the population of the population changeschanges..

EvolutionEvolution The The 1st organisms1st organisms were very simple and have were very simple and have

become complex over billions of years.become complex over billions of years.

SpeciesSpecies group of organisms that group of organisms that look look alike & can reproduce among alike & can reproduce among themselves.themselves.

EvolutionEvolution Many species have become Many species have become extinct,extinct, while while

others have taken their place.others have taken their place.

Japanese Wolf WolfJapanese Wolf Wolf

EvolutionEvolution

EvolutionEvolution-process by which -process by which

species change over species change over time.time.

AdaptationsAdaptations All organisms have adaptations which are All organisms have adaptations which are

traitstraits that help them that help them live in a certain live in a certain environment.environment.

AdaptationsAdaptations help organisms get help organisms get foodfood, avoid , avoid predators, predators, reproducereproduce, move from place to place, etc., move from place to place, etc.

StructuralStructural Adaptations Adaptations

• Appearing camouflagedAppearing camouflaged

• Webbed feet of a duckWebbed feet of a duck

• Long trunk of an Long trunk of an elephantelephant

BehavioralBehavioral Adaptations Adaptations

• Opossums play deadOpossums play dead

• A spider’s web spinningA spider’s web spinning

• Bird’s courting danceBird’s courting dance

MutationMutation A A sudden changesudden change in a gene is called in a gene is called mutationmutation..

If the mutation is If the mutation is helpfulhelpful, it will be kept and , it will be kept and passed ontopassed onto future generations and the future generations and the speciesspecies will changewill change. **A NEW SPECIES**. **A NEW SPECIES**

If the mutation is If the mutation is harmfulharmful, the individual , the individual organism will organism will diedie without passing on the without passing on the traittrait..

Charles Darwin’s Theory of Charles Darwin’s Theory of EvolutionEvolution

NaturalNatural Selection Selection

Nature Nature favorsfavors the the survival of organisms survival of organisms that are best that are best suited/suited/adaptedadapted for for survival in their survival in their environmentenvironment..

Parts of Natural SelectionParts of Natural Selection OverproductionOverproduction

Not all offspring Not all offspring willwill survivesurvive due to due to food food supply, living supply, living spacespace, or , or predators.predators.

Parts of Natural SelectionParts of Natural Selection Struggle for ExistenceStruggle for Existence

CompetitionCompetition among a among a species to species to survivesurvive. Only . Only a a fewfew will reproduce and will reproduce and others will die.others will die.

Parts of Natural SelectionParts of Natural Selection VariationVariation

Offspring are not alike. Offspring are not alike. They have different They have different traitstraits. With traits . With traits favorable to their favorable to their environmentenvironment, they are the , they are the ones who will ones who will survivesurvive..

FasterFaster StrongerStronger ColorsColors

Parts of Natural SelectionParts of Natural Selection Survival of the FittestSurvival of the Fittest

Some Some variationsvariations of an of an organism make them organism make them better suitedbetter suited for the for the environment and they environment and they will will survivesurvive..

Parts of Natural SelectionParts of Natural Selection Evolution of New speciesEvolution of New species

Organisms with Organisms with favorable traitsfavorable traits will will continuecontinue to to survive and survive and pass onpass on these traits to their offspring. these traits to their offspring. The organism with the The organism with the unfavorable traits will dieunfavorable traits will die. . Over many generations, the changes can result in Over many generations, the changes can result in the the appearance of aappearance of a

new speciesnew species..