Biol 301 1nd Edition Lecture 8 Outline of Last Lecture I. Historical ContextII. Adaption by Natural SelectionIII. GenesOutline of Current Lecture II. Microevolution/ macroevolutionIII. Hardy- Weinberg PrincipleIV. VariationCurrent LectureMicroevolution- Microevolution – the evolution of populations; affected by random processes and selection- Artificial selection – selection in which humans decide which individuals will breed; breedingis done with a preconceived goal for the traits in the population- Natural selection favors trait combinations that provide higher fitness to an individual. May be multiple ways to improve fitness that are favored by natural selection. Natural selection is an ecological process; individuals interact with their environment, and traits that lead to greater fitness in an environment are passed on- Industrial melanism – a phenomenon in which industrial activities cause habitats to become darker due to pollution; individuals possessing darker phenotypes are favored by selectionMacroevolution- Macroevolution – evolution at higher levels of organization including species, genera, families, orders, and phyla- Speciation – the evolution of new species- Phylogenetic trees – hypothesized patterns of relatedness among different groups such as populations, species, or genera- Allopatric speciation – the evolution of new species through the process of geographic isolation. Occurs when a single population is separated by a geographic event (ex. Formationof a river).- Sympatric speciation – the evolution of new species without geographic isolationThese 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.- Polyploidy – a species that contains three or more sets of chromosomes; can also give rise tosympatric speciation. This arises when homologous chromosomes fail to separate during meiosis, producing diploid gametes. o Happens more frequently in plants. Typically they produce larger flowers and fruits.- Evolution can produce key innovations that are highly usefulHardy Weinberg Principle- What must be true if no evolution is occurring? No migration, mutation.- 1=p^2+2pq+q^2, 1=p+q, p= AA, q= aa- Find recessive first*Variation- Some temporal variation in the environment is predictable; some is unpredictable (weather).- Weather – the variation in temperature and precipitation over periods of hours or days.- Climate – the typical atmospheric conditions that occur through the year, measured over many years. Events can be rare, but have large effects (tsunamis). Some variation occurs in regular intervals (forest fires). In general, the more extreme events occur less frequently.- Large-scale variation may be caused by factors like climate, land topography, and soil type. Small-scale variation is generated by factors such as plant structure and animal behavior. A particular scale of special variation may be important to one organism but not to another. Individuals moving through space experience spatial variation as a sequence in time.- The extent of the space affected by and event is usually related to an event’s duration in time.- All phenotypes result from genes interacting with environments- Phenotypic trade-off – a situation in which a given phenotype experiences higher fitness in one environment, whereas other phenotypes experience higher fitness in other environments- Phenotypic plasticity – the ability of a single genotype to produce multiple phenotypes. - When environmental variation results in phenotypic trade-offs, natural selection will favor the evolution of phenotypic plasticity. Many types of traits are plastic (behavior, growth, development, and reproduction). If spatial variation isn’t common, a single phenotype will be favored.- Acclimation – an environmentally induced change in an individual’s physiology can also be relatively rapid. Changes in morphology and life history are often relatively slow responses.- Adaptations in enemies – many species alter their growth, body shape, and behavior in response to the presence of predators. These alterations improve prey fitness by making it difficult for the predator to find or consume the prey.- Plants have the ability to respond to the presence of herbivores- Competition for resources – organisms have evolved a variety of phenotypically plastic strategies for high and low competition. Animals may spend more time looking for food or alter digestive morphology. Longer intestines can help extract more nutrients from ingesting food.- Hermaphrodites – individuals that can produce both male and female gametes; individuals are able to fertilize their eggs with their own sperm.- Inbreeding depression – the decrease in fitness caused by mating between close relatives due to offspring inheriting deleterious alleles from both the eggs and the