So what does evolution mean?So what does evolution mean?

Well, The Book Says:

Charles DarwinCharles Darwin

Charles DarwinCharles Darwin Took a trip on the S.S. Beagle to the Took a trip on the S.S. Beagle to the

Galapagos Islands to work as a naturalist.Galapagos Islands to work as a naturalist. Hypothesized that Hypothesized that Natural SelectionNatural Selection drove drove

evolution in his book, evolution in his book, On the Origin of SpeciesOn the Origin of Species.. He invented the concept- He invented the concept- Survival of the Survival of the

fittestfittest- - which actually means survival of the which actually means survival of the slightly better suited to a particular slightly better suited to a particular environment at a particular timeenvironment at a particular time

Darwin’s Theory : Darwin’s Theory : Natural Natural SelectionSelection

Environment limits Environment limits growth of populationsgrowth of populations Due to Due to variationsvariations

among individuals in a among individuals in a species, some species, some members of a members of a population population competecompete better for limited better for limited resources, so they resources, so they survive survive and and reproducereproduce, while , while others do not.others do not.

VARIATIONS• Differences in a species• Raw material for evolution• Caused by: 1) Crossing over

2)Chance Assortment3)Mutation

ADAPTATIONS: Variations that improvechances for survival!

Notice The Variation In These Individuals Of A Notice The Variation In These Individuals Of A House Finch PopulationHouse Finch Population

AdaptationsAdaptations

A variation that continues to exist A variation that continues to exist generation after generation and generation after generation and increases the organisms chance to increases the organisms chance to survive and reproduce (pass on its survive and reproduce (pass on its genes)genes)

• MORPHOLOGICAL

• CHEMICAL

• BEHAVIORAL

PhysicalPhysicalChemicalChemicalBehavioralBehavioral

PhysicalADAPTATION

PhysiologicalADAPTATION

BEHAVIORALADAPTATION

ADAPTATION•morphological?•Chemical?•Behavioral?

Artificial SelectionArtificial SelectionSelecting and Breeding the organisms with Selecting and Breeding the organisms with

the most desirible traits. the most desirible traits. Can you think how humans do this?Can you think how humans do this?

Dog BreedingDog Breeding

Horse BreedingHorse Breeding

Natural SelectionNatural SelectionDarwin thought that there must be a force Darwin thought that there must be a force

in nature that worked like artificial in nature that worked like artificial selection.selection.

That force came to be known as Natural That force came to be known as Natural Selection, the basis for evolution.Selection, the basis for evolution.

Individuals struggle to surviveIndividuals struggle to surviveCompetition for food (plants)Competition for food (plants)Escaping from predatorsEscaping from predatorsFinding MatesFinding MatesLocating ShelterLocating Shelter

Natural SelectionNatural Selection

http://www.nmsu.edu/~molbio/dog/nature.htm

Direct Evidence for EvolutionDirect Evidence for EvolutionMimicry – Structural Adaptation evolved in Mimicry – Structural Adaptation evolved in

some species where one species some species where one species resembles another. resembles another.

Camouflage – Structural adaptation that Camouflage – Structural adaptation that enables a species to blend with their enables a species to blend with their surroundingssurroundings

Bacterial resistanceBacterial resistance

MimicryMimicry

MimicryMimicry

MimicryMimicry

HornetFly

CamouflageCamouflage

CamouflageCamouflage

Why does this frog have funky Why does this frog have funky skin?skin?

Why does this fish have a large dot Why does this fish have a large dot on its back?on its back?

Bacteria (Direct Evidence)Bacteria (Direct Evidence)

Evidence Of EvolutionEvidence Of Evolution FossilsFossils Homologous Homologous

StructuresStructures Analogous StructuresAnalogous Structures Vestigial StructuresVestigial Structures Embryological Embryological

SimilaritiesSimilarities Macromolecule (DNA, Macromolecule (DNA,

RNA, Proteins) RNA, Proteins) SimilaritiesSimilarities

FossilsFossils

FossilsFossils

CamelsCamels

Homologous StructuresHomologous Structures Structures with Structures with

common evolutionary common evolutionary origins. Can be origins. Can be similar in similar in arrangement, arrangement, function, or both.function, or both.

Analogous StructuresAnalogous Structures Show that the Show that the

environment selects environment selects for certain abilities.for certain abilities.

Structures that do not Structures that do not have a common have a common evolutionary origin but evolutionary origin but are similar in functionare similar in function

Analagous StructuresAnalagous Structures

Vestigial StructuresVestigial Structures Body structure that Body structure that

has no function in a has no function in a present day organism present day organism but was probably but was probably useful to an ancestor.useful to an ancestor.

Vestigial StructuresVestigial Structures

Vestigial StructuresVestigial Structures

Vestigial StructuresVestigial Structures

EmbryologyEmbryology

DNA SimilarityDNA Similarity

The more similar the DNA, RNA or proteins The more similar the DNA, RNA or proteins between two organisms, the more recently they between two organisms, the more recently they shared a common ancestor.shared a common ancestor.