Evolution

Mrs. RagoBio

EvolutionCharles DarwinEnglish scientist who developed theory of evolutionStudied species on the Galapagos IslandsObserved the species to compare features from each

Natural SelectionMechanism for change in populationsOccurs when an organism with certain variations (characteristics) survive, reproduce, & pass on their variations to the next generationThese variations make the organism more likely to survive and reproduceReproduction in Natural SelectionFavorable traits make individual more likely to survive & reproduceIndividuals with the best traits pass them on to their offspringConvergent EvolutionProcess by which different species evolve similar traits Different ancestors but species with similar traits that have evolved to deal with the problem

Divergent evolution Descendants of a single ancestor diversify into species that each fit different parts of the environment

Coevolution When 2 or more species have evolved adaptations to each others influence

Artificial SelectionBreeding organisms to produce offspring with identical traitsExample: breeding pure bred dogs

On the Origins of SpeciesBook by Charles DarwinFirst book on evolution

Structural AdaptationsChanges that have developed in an organisms form over timeExample: thorns on some plantsTake a long time to occurMillions of years

MimicryStructural adaptation that allows one species to resemble another speciesUseful for a harmless species to resemble a harmful species, so that predators avoid the harmless species

Coral snake- venomous & deadlyKing snake-non venomous CamouflageAn adaptation that allows a species to blend into their surroundings and avoid predators

Physiological adaptationsOccur much fasterChanges in an organisms metabolic processesExample: resistance to penicillin, insects & weeds resistant to specific pesticidesEvidence for EvolutionFossil recordShows evidence of evolution but it is incomplete

AnatomyHomologous structuresSimilar structures that come from a common ancestor

Analogous StructuresSimilar structures that are similar because they are used for the same purpose

Vestigial StructuresA body structure that has no function in a present-day organism but was probably useful to an ancestorExample: wings of an ostrich

EmbryologyEmbryo is the earliest stage of growth & development of both plants & animals

BiochemistryEvidence for evolution, shows similarities in DNA or RNAAtmosphere of Early EarthLarge meteor impacted earthMore comets hit earth and brought ice with them which along with gases from volcanoes produces the water we now find on earthAtmosphere of Early EarthVery little free oxygenWater vaporCarbonNitrogen

Evolution of photosynthesisArchaebacteriaDo not require oxygen First group to developCyanobacteriaProduce oxygen from their chemical reactionsThis changed earths atmosphere

Early EarthVery hotLots of volcanoes meteoritesLots of gasesHumans would never have survived early earth