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