Evidence ofEvolution

More proof

• Fossils tell us about what used to be here…

– But, it takes a long time for fossils to form…

• We can also rely on our memories andrecords of things that have existed sincehumans have been around…

More proof

• Evolution is not just something thathappened in the past. It is constantlyhappening.

– In some cases, it happens right in front of us,without us noticing…

– But how do we know, if we’re not looking atfossils??

More proof

• There are other kinds of evidence thatshows evolution happens…

– Some of this evidence we can see just bylooking at stuff with our naked eye, while otherare at the molecular level…

• Homologous Structures

• Think back to genetics… what did “homologous”mean? (i.e. “homologous chromosomes”)

• Homologous means “same” or “match”

– So, a homologous structure is a body part thathas the same function in completely differentorganisms

Anatomical Evidence

• AnalogousStructures

– Body parts of differentorganisms that havethe same function butdifferent structures

• ex: Bird’s Wing &Butterfly’s Wing

Anatomical Evidence Anatomical Evidence

• Vestigial Structures

– Body parts with no apparent functions

– The body parts were probably useful to theancestral species, then stopped being usefulbut never disappeared

• Human wisdom teeth and appendix• Tiny hip bones in snakes• Femur in whales

AnatomicalEvidence

Embryological Evidence

– Study of early growth stages & developmentof embryos

– The embryos of different organisms look verysimilar

• Similar genes at work

– The DNA sequences which control earlydevelopment remain unchanged because oflittle or no mutations

Biochemical Evidence

• The study of the molecules that make up anorganism

• All organisms use DNA & RNA to carryinformation

• All living things need water & energy

• All organisms synthesize proteins

Biochemical Evidence Adaptations

• When an organism blends in with its environment, itis called camouflage– i.e. chameleons

• When a non-dangerous organism evolves to looklike a dangerous organism, it is called mimicry– i.e. the viceroy butterfly mimics the Monarch butterfly– i.e. the king & milk snakes mimics the coral snake

• When a dangerous organism advertises itself asbeing dangerous, it is called warning coloration– i.e. poison dart frogs

Adaptations

camouflage

Adaptations

mimicry

Adaptations

warning coloration