2 Evolution Change over time The processes that have transformed life on earth from it’s earliest forms to the vast diversity that characterizes it today.Theory-a well-supported testable explanation of events that have occurred in the natural world.
3 Old Theories of Evolution Jean Baptiste Lamarck (early 1800’s) proposed:“The inheritance of acquired characteristics”He proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime, which it passes on to its offspring.
4 “The Inheritance of Acquired Characteristics” Example:A giraffe acquired its long neck because its ancestor stretched higher and higher into the trees to reach leaves, and that the animal’s increasingly lengthened neck was passed on to its offspring.
5 Charles Darwin http://Early Life of Charles Darwin Darwin set sail on the H.M.S. Beagle ( ) to survey the South America to collect plants and animals.On the Galapagos Islands, Darwin observed species that lived no where else in the world.These observations led Darwin to write a book.
7 Charles Darwin Influences James HuttonProposed that Earth is shaped by geological forces that took place over long periods of time.Thomas MalthusProposed that famine, war and poverty limited human population
8 Charles Darwin Influences Charles Lyellled Darwin to realize that natural forces gradually change Earth’s surface and that the forces of the past are still operating in modern times.
9 Charles DarwinWrote in 1859:“On the Origin of Species by Means of Natural Selection”Artificial selection-humans selected the genetic variation that they found usefulProposed a mechanism for evolution:NATURAL SELECTION- nature selected the genetic variation that they found useful
10 Artificial SelectionThe selective breeding of domesticated plants and animals by man.Question:What’s the ancestor of the domesticated dog?Answer: WOLF
11 Natural SelectionIndividuals with favorable traits are more likely to leave more offspring better suited for their environment.Can’t be seen but results shownExample:English peppered moth (Biston betularia)- light and dark phases
12 Evolution by Natural Selection Struggle for ExistenceMembers of species regularly compete for food, living space, and other necessities.Survival of the FittestFitness: ability of an individual to to survive and reproduce in its environmentAdaptation: inherited characteristic that increase an organism chance of survivalSURVIVAL OF THE FITTEST-Survive and reproduce the most successfully
17 Evidence of EvolutionFossil Record: Fossils and the order in which they appear in layers of sedimentary rock (strongest evidence).Ancestral traits-primitive features that do appear in ancestral formDerived traits-newly evolved features that didn’t appear in ancestors
18 Evidence of EvolutionBiogeography: Geographical distribution of species.
19 Evidence of Evolution Comparative Anatomy Homologous Structures -Structures that has different mature form but develop from same embryonic tissue.Vestigial structure-Structure that is no longer functioningAnalogous structures-Structures that has same mature form but develop from different embryonic tissue.
20 Evidence of Evolution 4. Comparative embryology Study of structures that appear during embryonic development.5. Molecular biology:DNA and proteins (amino acids)
21 AdaptationAdaptation: a trait shaped by natural selection that increases an organism's reproductive successFitness: a measure of the relative contribution success of the following generationTypes of adaptationCamouflageMimicryAntimicrobial resistance
22 Summary of Darwin Theory Individual organisms differ and some of the variation is heritable.Organisms produce more offspring than can survive and many that survive don’t reproduceThey will compete for limited resourcesEach unique organisms has different advantages and disadvantages in the struggle of existence.Individuals best suited to their environment and reproduce most successfully.Species alive today are descended with modification from ancestral species that lived in the distant pastSingle tree of life.