BIO A01 Lecture Notes F2024 PDF

BIO A01 | Life on Earth: Unifying Principles | Microevolution DATE LECTURE TOPIC TEXTBOOK Sep 03 01 Course Introduction & Syllabus Ch 1 Sep 05 02...

BIO A01 | Life on Earth: Unifying Principles | Microevolution DATE LECTURE TOPIC TEXTBOOK Sep 03 01 Course Introduction & Syllabus Ch 1 Sep 05 02 Microevolution & Population Genetics Ch 1.4 Ch 20.1, 20.2 Sep 06 03 Hardy-Weinberg & the Agents of Evolution Ch 20.3, 20.4 Sep 10 04 Selection & Maintaining Variation Ch 20.4, 20.5, 20.6 Sep 12 05 Darwin and Evolution n/a Sep 13 06 Evidence for Evolution I Ch 22 Sep 17 07 Evidence for Evolution II Ch 22 Sep 19 08 Classification & Phylogeny Ch 21 & 22 Sep 20 09 Phylogeny II & Species Ch 21 & 22 Sep 24 10 Speciation Ch 21 Sep 26 11 Eukaryotic cells - Origins & Diversity Ch 25 Sep 27 12 Evolution & Development (+ Review) Ch 18.2 & 18.3 © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution BIO A01: Lecture 2 Microevolution: Genetic Changes within Populations Ch 1.4, Ch 20.1, Ch. 20.2 Prof. Scott MacIvor Instructor, Module 1 Thursday, September 5th, 2024 © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Volunteer Note Takers Needed for AccessAbility Services AccessAbility Services is recruiting volunteer note takers to assist students with disabilities. Volunteers play an essential role in allowing students to access course materials, which they may otherwise not have access to. Co-Curricular Record (CCR) Approved Position 1.Go to https://www.utsc.utoronto.ca/ability/myaims-0 and select myAIMS for Volunteer Notetakers 2.Follow the simple step-by-step process to register. 3.Upload notes files into the AccessAbility Services myAIMS note taking portal If you have questions please contact AccessAbility Services (416) 208-2662 or [email protected] © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution The concept of time……and life on Earth © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution On this timeline, which location roughly depicts when life originated on Earth? 15m 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Earth forms – 4.5 billion years ago September 5, 2024 On this timeline, which location roughly depicts when humans first evolved on Earth? © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Event Distance (m) Time (Mya) Formation of Earth 15 4500 First evidence of ‘life’ – self-replicating 13 3800 Oxygen-producing cyanobacteria 9 2700 Significant oxygen in atmosphere 8 2500 Multicellular organisms 2 600 Plants move onto land 1.55 465 Amphibians emerge from water Trilobites 1.2 1.17 370 350 !!!!! Permian-Triassic extinction – 99% of life 0.83 250 Age of dinosaurs 0.80 240 Pangaea breaks 0.67 200 Cretaceous-Paleogene extinction (dinosaurs + 2/3 life) 0.22 66 Mammals 0.20 60 Hominins 0.01 3 Modern humans 0.0007 0 15m 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Earth forms – 4.5 billion years ago September 5, 2024 © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution All life, past & present, are connected by a common ancestor © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution What is Evolution? © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution What is Evolution? Basic definition: change through time ‘decent with modification’ Darwin thought, ‘pangenesis’? What is biological evolution? change in allele or genotype frequencies in populations over time 1) genetic changes occur in populations 2) individuals do not evolve © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Evolution explains the unity of living things and the diversity of life - Theodosius Dobzhansky Hawaiian Drosophila radiation (1930s) © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Adaptive radiation Organisms diversify rapidly from an ancestral species when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches A B © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution How does evolution affect my life? © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution How does evolution affect my life? Penicillin Product of Penicillium mold (Alexander Fleming, 1928) Represents an evolved response to bacteria First antibiotic drug based on a naturally occurring substance Four years of use lead to 14% of Staphylococcus strains resistant Greatly reduced losses in WW2 …by 1950 – more than 50% resistant! © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution How does evolution affect my life? Penicillin: today Continue to develop new strains Identify resistance where it occurs Need to minimize dependence on antibiotics Alexander Fleming – Nobel prize in 1945 Resistant bacteria still kills 30,000 to 40,000 Americans each year © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution How does evolution affect my life? COVID-19! SARS-COV-2 virus continues to evolve where it persists Mutations lead to variation, some could be exceptionally problematic Variants could have different properties: virulence, dispersal, symptoms © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Microevolution / Macroevolution Chapter 20 Microevolution: changes within species natural selection other evolutionary forces Chapter 21 Chapter 22 Macroevolution: changes between species © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Microevolution Microevolution depends on… Heritable variation in genetics of a population A population is… Individuals of species at same time and place Traits can be under strong natural selection e.g. antibiotic resistance...but natural selection forces can vary in type and intensity through time. Can be unpredictable! © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Phenotypic Variation Heritable variation in appearance and/or function Qualitative variation Characteristics with distinct states Polymorphisms: Distinct variants of character e.g., presence of spines = Yes or No The two-spot ladybug, Adalia bipunctata © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Phenotypic Variation A broad, low curve indicates a lot of variation Heritable variation in appearance and/or function among individuals. Quantitative variation Number of individuals A high, narrow Characteristics with a range of variation curve indicates little variation Controlled by multiple genes among individuals. Can be measured (e.g., height) mean Measurement or value of trait © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Phenotypic Variation: European Garden Snails Number of individuals Measurement or value of trait © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Phenotypic Variation: Bahamian Land Snails Number of individuals Measurement or value of trait © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Genes and Environment Genotypes and phenotypes are not completely correlated Phenotypic variation is due to genetics, environmental differences, or both Only genetic component of phenotype are heritable Are there experiments we can use to determine connection between phenotypes and genotypes? 1. Keep genetics constant, vary environment 2. Breeding and selection experiments © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution 1. Keep genetics constant (e.g., clones), vary environment © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution 2. Breeding and selection experiments How to determine if the variation is influenced by genetics? This is important since evolution can only act on heritable variation © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Mice seem to vary in their level of physical activity Is this variation due to underlying genetic variation? © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Genetics and activity in mice Experiment: 8 experimental mouse lines 4 control (no selection) 4 experimental (breed only most active) 10 generations of breeding © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Genetics and activity in mice There was underlying genetic variation for activity level © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Assessing genetic variation…when phenotype = genotype Can assess observable phenotypic variation (…and understand heredity!) e.g., Augustinian monk, sweet pea (Lathyrus odoratus), ‘Mendelian genetics’, mid- 1800s Gregor Mendel © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Allele 1 What can cause genetic Generation 1 variation? Mutation No mutation Allele 2 Allele 1 1) New alleles (from mutations) Generation 2 Germ-line mutations No mutation Mutation Occur in the reproductive cells Allele 2 Allele 3 Allele 1 Passed on to the next generation Generation 3 2) Recombination From crossing over, independent assortment, random fertilization Allele 4 Generation 4 © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution The power of selection on genetic variation © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution There is considerable genetic variation in populations Two examples of selection (dogs and Brassica) are a testament to this How do we assess this genetic variation? How can we use this variation to understand evolution?? © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Population genetics The study of patterns in genetic variation in populations For evolution to occur, individuals within a population must differ genetically A population is a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring Individuals within a population are more closely related to each other than members of other populations Different populations of the same species may be isolated from each other such that gene flow is rare © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution The gene pool The sum of all alleles at all gene loci in all individuals within a population Characterizes a population’s genetic makeup Used to identify the genotypes and calculate genotype frequencies Genotype! © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution The gene pool Used to identify the genotypes and calculate genotype frequencies Knowing that taxa of interest are diploids and have two alleles of each gene (e.g., AA, Aa, or aa), we can calculate allele frequencies Genotype! © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Calculating genotype and allele frequencies AA = 12 Aa = 2 aa = 1 Total = 15 AA Aa aa © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Assessing Genetic Variation OK: Assess observable phenotypic variation (when phenotype = genotype) Ladybug, Mice examples Better: Relative genotype frequency and relative allele frequency Mendel’s pea experiments ‘Snapdragons’ (next class) Best: Measure genetic variation directly Many high-throughput methods for DNA sequencing (whole genome or targeted regions). Many based on the Polymerase Chain Reaction (PCR) © J S MacIvor, UTSC 2024  BIO A01 | Life on Earth: Unifying Principles | Microevolution Next Lecture: Friday Sept 6th Evolutionary Agents Reading: Chapter 20.3, 20.4 © J S MacIvor, UTSC 2024