BCOR 12 1st Edition Lecture 2 Outline of Last Lecture I. Major Themes in BiologyII. Chapter 22 – Descent with ModificationOutline of Current Lecture I. Evidence for EvolutionII. Evolution: Process and a patternIII. Darwin’s Main Observations and inferencesIV. Important Points about Natural SelectionCurrent Lecture- Fossils are evidence of evolutiono Ex. Beluga whale bones were found in the swamps of Charlotte, VT, the landlocked stateof New EnglandArtificial Selection – selective breeding of domesticated plants and animals by humans- Increases the frequency of traits in the animals and plants desired by HUMANS- Desired traits are (usually) not beneficial to an animals in its natural habitat- Ex. A Dalmatian doesn’t have coloring like that of a wolf to hide and survive in the wilderness and therefore would be spotted by its prey quickly. Lamark was one of the very first scientists to propose a mechanism for evolutionary change. He is knownfor his hypothesis being incorrect.Lamark’s Theory of Evolution:1. Use and disuse – parts of the body being used often and extensively by the organisms will grow longer during the lifetime to benefit the organsim’s survival a. Ex. A giraffe has a very long neck to be able to reach the leaves to eat. Lamark’s hypothesis says the giraffe’s neck stretched DURING the period of it’s lifetime2. Inheritance of acquired characteristicsa. Ex. Characteristics (the long neck of the giraffe) were acquired DURING the lifetime of the organismLamark thought that the DNA (inheritance) changed during the organism’s lifetime, which we now know is indeed incorrect.These 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.Charles Darwin was the first scientist to demonstrate a mechanism of evolution with evidenceDuring his travels overseas, Darwin came up with this question as he saw a great variety in species that were widely similar:Could a new species arise by the gradual accumulation of adaptations to different environments?Adaptation – inherited characteristics of an organisms that enhances its survival and reproduction in a particular environment - they are born with the adaptation, they do not acquire it during their lifetimeDarwin came up with this question based on his observations at the Galapagos Islands and on the South American mainland.Observations:- Plants and animals found on the islands were very similar yet distinctively different to those on the mainland- There was variation among organisms from island to island (tortoises are a great example)Variation – differences between members of the same species - Variation drives natural selectionEx. Sailor’s could spot the different between tortoise to tortoise on the islandsMUTATIONS are the molecular source of variation. They are the ONLY way to get a allele in the DNA code.Gene expression – expressing DNA as proteins, DNA  RNA  Proteins,Genotype  phenotypeEvolution by Natural SelectionNatural Selection – the process where organisms inherit certain characteristics that make them much more likely to survive and reproduce and pass on these chosen characteristics than those with other less favorable characteristicsEx. Peppered moths are characteristically white with black spots, however in the 19th century industrialization and coal fires made towns rather sooty and black making the white moths more visible to predators that the black moths. This caused the black moths to survive and reproduce much more often than that of the white moths. This caused the numbers of black moths to rise. - “Survival of the fittest” doesn’t count in natural selection. Reproduction is what counts- What counts is Fitness – the measure of how many offspring are produced and how many of these offspring reproduce themselvesDarwin made 3 major observations during his travels:1. Within a population there is a great variety in traitsa. Ex. Not all humans look the same. We can be of different skin colors, height, weight, eye color, etc.2. Traits are inherited from parents to offspringa. This is through DNA3. Species often produce more offspring that the environment can support. Due to lack of food andother resources, many offspring do not survive.Darwin made two inferences based on these observations:1. Individuals who had inherited traits that infer a high survival and reproduction in a given environment will leave more offsprings2. This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable trains in the population over generationsIn other words: those who have the favorable traits to survive will produce offspring with the traits to survive and the favorable traits will later become the norm of the population over the years.Natural SelectionMain Ideas from Charles Darwin’s book Origin of the Species1. Descent with modification explains life’s unity and diversity2. Natural selection brings about the match between organisms and their environmentImportant points about Natural Selection:1. Natural selection is an editing mechanism, not a creative force2. Natural selection favors traits that increase fitness in the current, local environment In other words: Natural selection edits out the unfavorable traits so that the favorable traits that best suit the population to survive in their environment at that current time will pass on to further generations. The favorable traits are bound to change over time as the environment