Evolution of evolutionary thought:Prevailing view until 1800s:Species=fixed types (didn’t change over time)Focus on the differences between speciesIdea that some species were more complex or “better” (humans at the top, plants at the bottom)No knowledge of genetics in this time periodBy early 1800’s increasing recognition that species evolveLamarck proposed the first potential mechanism of evolutionInheritance of acquired characteristics: individuals changeCharles Darwin and Alfred Russell Wallace were naturalists during the 1800’sWent on voyage around the world making observationsIndependently proposed idea of natural selectionPublished in 1858 when Darwin discovered Wallace had the same theoryThree major propositions:1. species change over time2. descent with modification: species share a common ancestor and have diverged over time3. changes in species are caused by natural selectionDarwin compared process of natural selection to the process of artificial selection using pigeons- all bread from one bird that evolvedDifferent breeds of dogs all belong to the same species (wolf)Dog Breeders selectively mate dogs with desirable phenotypesIn order for change to occur, selected phenotypes must be passed on to offspring from genesIn dogs, body size is determined, in part, by IGF1 gene, which has 2 possible alleles, I and BAlleles work in a dominance way- selecting I for large and B for smallPhenotypes are influenced by the environment- wolves with thick/ thin fur and their environmentRequirements for Natural Selection to Occur:1.Variation: individuals in a population have variable phenotypes (traits)2. Heritability: phenotypic variation is heritable (passed on to offspring)3. Differential reproduction: has to be unequal reproductive success in the population and individuals with favorable traits are more likely to survive (have higher fitness)Natural Selection: he process that causes favorable traits to be passed on to future generationsResults of NS: overall population evolves and becomes better adapted to the current environmentNatural selection acts on individualsEvolution is seen at the level of populationBIO 130 1st Edition Lecture 3Outline of Last Lecture I. Phenotypes, Genes, and the EnvironmentOutline of Current Lecture II. Evolution of Evolutionary ThoughtIII. Charles DarwinIV. Natural SelectionCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Evolution of evolutionary thought:- Prevailing view until 1800s:- Species=fixed types (didn’t change over time)- Focus on the differences between species- Idea that some species were more complex or “better” (humans at the top, plants at the bottom)- No knowledge of genetics in this time period- By early 1800’s increasing recognition that species evolve- Lamarck proposed the first potential mechanism of evolution- Inheritance of acquired characteristics: individuals change - Charles Darwin and Alfred Russell Wallace were naturalists during the 1800’s- Went on voyage around the world making observations - Independently proposed idea of natural selection- Published in 1858 when Darwin discovered Wallace had the same theory- Three major propositions:1. species change over time2. descent with modification: species share a common ancestor and have diverged over time- 3. changes in species are caused by natural selection- Darwin compared process of natural selection to the process of artificial selection using pigeons- all bread from one bird that evolved- Different breeds of dogs all belong to the same species (wolf)- Dog Breeders selectively mate dogs with desirable phenotypes- In order for change to occur, selected phenotypes must be passed on to offspring from genes- In dogs, body size is determined, in part, by IGF1 gene, which has 2 possible alleles, I and B- Alleles work in a dominance way- selecting I for large and B for small- Phenotypes are influenced by the environment- wolves with thick/ thin fur and their environmentRequirements for Natural Selection to Occur:1.Variation: individuals in a population have variable phenotypes (traits)2. Heritability: phenotypic variation is heritable (passed on to offspring)3. Differential reproduction: has to be unequal reproductive success in the population and individuals with favorable traits are more likely to survive (have higher fitness)- Natural Selection: he process that causes favorable traits to be passed on to future generations- Results of NS: overall population evolves and becomes better adapted to the current environment- Natural selection acts on individuals- Evolution is seen at the level of