Introduction to Systematics (Course Outcome 1) PDF

Official Business Introduction to Systematics Course Outcome 1 Official Business Lecture Objectives At the end of this lecture, students should be able to: ✓ define evolution and relate its im...

Official Business Introduction to Systematics Course Outcome 1 Official Business Lecture Objectives At the end of this lecture, students should be able to: ✓ define evolution and relate its importance to Systematics ✓ identify the factors resulting to evolution ✓ discuss the conditions for a Hardy-Weinberg Equilibrium Official Business Systematics study of biological diversity and the relationships among organisms Taxonomy naming, describing, and classifying organisms SYSTEMATICS Phylogenetics determining evolutionary history and relationships Official Business Evolution a process by which modern organisms have descended from ancient ancestors results from any process that causes a change in the genetic composition of a population Population Genetics – study of genetic variation within populations and how it changes over time and geographical space https://images.app.goo.gl/37hcLp2WiS6Cq9Cj7 Official Business Levels of Biological Organization Official Business Genetic variation refers to the different alleles of genes found within individuals of a population Official Business RECALL What is the difference between a gene and an allele? Official Business How does a genetic composition change? What results to genetic variation? 5 Agents of Evolutionary Change Official Business Gene Frequency also known as allele frequency frequency of an allele within a population Official Business Gene Pool composed of all the alleles for all genes in all the members of a population Fixed Allele all members of the population have only one allele for a particular trait https://images.app.goo.gl/ixDomgojFb3w5VhS7 Official Business Genetic Variations allow adaptation to occur. It increases the survival rate of species. Official Business 5 Agents of Evolutionary Change Official Business Mutation change in the specific sequence of nucleotides in DNA Mutations change the composition of the gene pool. New alleles are introduced and allele frequencies change. Official Business Migration movement of individuals or species or populations from one area to another enables gene flow Official Business Nonrandom Mating selection of mates is influenced by phenotypic differences individuals or species are more or less likely to mate with individuals of a particular genotype than others Official Business Genetic Drift change in gene frequency due to change Official Business Genetic Drift: Bottleneck Effect happens when the size of a population is severely reduced due to sudden change in environment and/or natural disasters Official Business Genetic Drift: Founder Effect a small group of individuals isolated from a larger population caused by migration and genetic drift Official Business Selection individuals with one phenotype leave more surviving offspring in the next generation than individuals with an alternative phenotype Artificial Natural Selection Selection Official Business Artificial Selection humans (breeders) select which organisms with desirable characteristics get to reproduce Official Business Natural Selection a process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype or genetic composition Adaptation a process which enables organisms to adjust to their environment to ensure survival genetic changes that decrease the probability of capture by a predator Official Business Selection to avoid Predators Pocket mice from the Tularosa Basin of New Mexico whose color matches their background. Black lava formations are surrounded by desert, and selection favors coat color in pocket mice that matches their surroundings. Genetic studies indicate that the differences in coat color are the result of small differences in the DNA of alleles of a single gene. Official Business Selection to match climatic conditions Enzyme allele frequencies vary with latitude Lactate dehydrogenase in Fundulus heteroclitus (mummichog fish) varies with latitude Enzymes formed function differently at different temperatures North Latitudes: Lactate dehydrogenase is a better catalyst at low temperatures Official Business Selection for pesticide and microbial resistance The resistance allele of a pen gene decreases the uptake of insecticide. Official Business Selection for pesticide and microbial resistance Allele of the kdr and dld-r genes decrease the number of target sites, thus decreasing the binding ability of the insecticide. Official Business a mode of natural selection in which members of Sexual one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with Selection members of the same sex for access to members of the opposite sex (intrasexual selection) Official Business Hardy-Weinberg Equilibrium No change in gene frequency over generations = no evolution Official Business Conditions for Hardy-Weinberg Equilibrium NO MUTATION NO GENE FLOW no change in genetic no migration takes composition, no NO NATURAL place SELECTION change in genotypes and phenotypes all organisms are LARGE assumed to have the POPULATION SIZE same fitness RANDOM MATING infinite number of no preference for species particular traits Official Business Conditions for Hardy- Weinberg Equilibrium If at least one of NO MUTATION these RANDOM MATING conditions is not met, NO GENE FLOW evolution takes LARGE POPULATION SIZE place within the population. NO NATURAL SELECTION Official Business Hardy-Weinberg GENE: Equilibrium ** eye color used for determining the genotypic frequency ALLELE: ** E – black (dominant) ** e – brown (recessive) GENOTYPES: ** EE ** Ee ** ee Official Business Hardy-Weinberg Equilibrium ALLELE (GENE) FREQUENCY p+q=1 p = frequency of the dominant allele q = frequency of the recessive allele Questions? shs.mapua.edu.ph Official Business Lecture Objectives At the end of this lecture, students should be able to: ✓ define evolution and relate its importance to Systematics ✓ identify the factors resulting to evolution ✓ discuss the conditions for a Hardy-Weinberg Equilibrium Official Business Next Lecture: - Evidences of Evolution - Speciation Official Business Official Business Introduction to Systematics Course Outcome 1 Official Business Evidences of Evolution Official Business Evidences of Evolution MICROEVOLUTION MACROEVOLUTION occurring on a large scale beyond the level of occurring on a small scale within a specific single single species (large scale changes in gene population frequency) small scale changes in gene frequency new species formation (intraspecies genetic change) re-arranged or altered genetic information deletion or addition in the gene changes occur over a short period of time changes occur over a long time period EXAMPLE: EXAMPLE: development of feathers, development of new strains of bacteria and viruses vertebrates from being invertebrates Official Business Evidences of Evolution DIVERGENT EVOLUTION CONVERGENT EVOLUTION two or more species evolved (diverged) from a two or more distinct species share a common trait common ancestor not due to a common ancestor Official Business Evidences of Evolution Official Business Natural Selection a process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype or genetic composition EXAMPLE: Darwin’s Galapagos Island Finches Official Business Industrial Melanism a phenomenon that occurs when individuals within species that have darker feathers, fur, or skin, become more prevalent in the population because these are at an advantage, given the soot and pollution in an industrialized area If pollution persists for multiple generations, individuals with dark coloring may be selected for and individuals with lighter coloring are selected against. Lighter individuals are at a disadvantage in the polluted environment. EXAMPLE: decrease of light-colored peppered moths in polluted areas Official Business Artificial Selection Official Business Direct Observation evidences of small-scale evolutionary changes directly observed in an organism with short life cycles Official Business Direct Observation Official Business Direct Observation Official Business Fossil Records preserved remains of once-living organisms biological diversity through time Official Business Types of Fossils CARBON FILM carbon impression left on sedimentary rocks ORIGINAL REMAINS preserved by nature (frozen in ice, dried, desiccated inside caves) Official Business Types of Fossils PETRIFIED organic materials that are converted into stone TRACE FOSSILS record of movements and behaviors of the organism Official Business Anatomical Evidence for Evolution HOMOLOGOUS STRUCTURES structures with different appearances and functions that all derived from the same body part in a common ancestor Official Business Anatomical Evidence for Evolution EMBRYONIC HOMOLOGY Embryos of different organisms often are similar in the early stages of development but become more different as they develop. Official Business Anatomical Evidence for Evolution VESTIGIAL STRUCTURES Features present in modern animals that are no longer functional, but resemble structures their ancestors possessed. Official Business Anatomical Evidence for Evolution PSEUDOGENES fossil genes traces of previously functioning genes non-functional DNA segments in modern organisms that are unable to code for proteins Official Business Anatomical Evidence for Evolution MOLECULAR HOMOLOGIES similarity in DNA and amino acid sequences (same genes) HOMOLOGOUS GENES two (2) or more genes derived from the same ancestral gene Official Business Anatomical Evidence for Evolution MOLECULAR HOMOLOGIES similarity in DNA and amino acid sequences (same genes) HOMOLOGOUS GENES two (2) or more genes derived from the same ancestral gene Official Business Biogeography study of the geographic distribution of species reveals that different geographical areas sometimes exhibit groups of plants and animals of similar appearance even though the organisms may be only distantly related Official Business Biogeography Official Business Evidences of Evolution Official Business Official Business Introduction to Systematics Course Outcome 1 Official Business Biological Species Concept Official Business Biological Species Concept species (group of organisms) is composed of populations whose members mate with each other and produce fertile offspring Reproductively Isolated populations whose members do note mate with each other or who cannot produce fertile offspring belong to a different species (groups of organisms) Official Business Geography of Speciation: Allopatric a geographic barrier separates the populations and prevents them from interbreeding and reproduce causes the population in each geographical location to have a change in genetic composition and form new species. Official Business Geography of Speciation: Sympatric speciation forms in the same area and it is due to barriers that prevent it to happen TYPES OF BARRIERS ✓ Pre-zygotic Barriers ✓ Post-zygotic Barriers Official Business Reproductive barriers to successful reproduction Isolating prevent genetic exchange between species Mechanisms Official Business Pre-zygotic Isolating Mechanisms prevent the formation of zygotes Post-zygotic Isolating Mechanisms prevent the proper functioning of zygotes Official Business Pre-zygotic Isolating Mechanisms: Ecological Isolation species occur in the same area but they occupy different habitats and rarely encounter each other Official Business Pre-zygotic Isolating Mechanisms: Behavioral Isolation species differ in their mating rituals Official Business Pre-zygotic Isolating Mechanisms: Behavioral Isolation Lacewings are small insects that rely on signals produced by moving their abdomens to vibrate the surface on which they are sitting to attract mates. Female lacewings detect the calls as they are transmitted through solid surfaces. They can distinguish calls of different species and respond only to individuals producing their own species calls. Official Business Pre-zygotic Isolating Mechanisms: Behavioral Isolation Other species rely on the detection of chemical signals called pheromones. When female moths are ready to mate, they emit such chemical signals that males can detect at great distances. Official Business Pre-zygotic Isolating Mechanisms: Behavioral Isolation Some species use electroreception. African and South Asian fishes have specialized organs in their tails that produce electrical discharges and electroreceptors on their skins to detect them. Male fishes can distinguish between signals produced by their own and other, co- occurring species, probably based on differences in the timing of the electrical pulses. Official Business Pre-zygotic Isolating Mechanisms: Temporal Isolation species reproduce in different seasons or at different times of the day Official Business Pre-zygotic Isolating Mechanisms: Mechanical Isolation shape and structural differences between species prevent mating no compatible sex organs Official Business Pre-zygotic Isolating Mechanisms: Prevention of Gamete Fusion gametes of one species functions so poorly with the gametes of another species or within the reproductive tract of another species Official Business Post-zygotic Isolating Mechanisms: Hybrid inviability or infertility Hybrid embryos do not develop properly Hybrid adults do not survive in nature Hybrid adults are sterile or have reduced fertility Official Business Adaptive Radiation rapid increase in the number of species within a common ancestor characterized by great ecological and morphological diversity requires both speciation and adaptation to different habitats Official Business Learning Checkpoint (Recitation) Official Business Learning Checkpoint 1. When do species become reproductively isolated? 2. What is the difference between allopatric speciation and sympatric speciation? 3. What is the difference between pre-zygotic and post- zygotic isolating mechanisms? Official Business Learning Checkpoint Official Business Next Meeting: Cladogram and Phylogenetic Trees Official Business Official Business Introduction to Systematics Course Outcome 1 Official Business Systematics Official Business Systematics diversification of life forms relatedness of organisms develop phylogenetic trees Linnaean Classification ✓ 3 Domains of Life ✓ Five-Kingdom System Official Business Systematics provide scientific names for organisms describe, identify, and classify organisms investigate evolutionary species environmental adaptation Internal Use Taxonomy naming, describing, classifying organisms SYSTEMATICS Phylogenetics evolutionary history Official Business Phylogenetics study of constructing the evolutionary history of a group of organisms by identifying shared, heritable traits that evolved in a common ancestor CHARACTER DERIVED TRAIT CHARACTER a character present in a heritable and observable STATES group under consideration trait two or more forms of a but not in any of the character group’s ancestors Official Business Phylogenetic Tree a branching diagram that shows the evolutionary history of group of organisms Official Business Phylogenetic Tree evolutionary relationships are supported by molecular evidence (e.g., DNA, RNA, proteins) evolutionary distance: accurate estimation of the amount of evolution that has occurred between sequences by accounting for unobserved changes evolutionary time: how evolution occurs over time Official Business Cladogram a branching diagram that shows the hypothetical evolutionary relationships of organisms used to generate a phylogenetic CLADE tree group of organisms that include an ancestor species and all of its descendants classification system that involves the categorization of organisms based on shared characters Official Business Cladogram Only (a) is considered a clade. Official Business Cladogram Official Business Cladogram Official Business Constructing a Cladogram 1. Make a table with the organisms (columns) and characters/traits (rows) being considered. 2. Mark the characters/traits that fit the organisms. 3. Determine the ancestral character (a trait that all organisms have). 4. Identify the derived traits (shared by organisms). 5. Draw the cladogram. Official Business Constructing a Cladogram: Example Organisms: Shark Goldfish Frog Primates Birds Official Business Constructing a Cladogram: Example Characters/Traits: eukaryotic cell bony skeleton four limbs Hair eggs with shells Official Business Step 1: Make a table. Sharks Goldfishes Frogs Primates Birds Eukaryotic Cell Bony Skeleton Four Limbs Hair Eggs with Shells Official Business Step 2: Mark the characters/traits that fit the organisms. Sharks Goldfishes Frogs Primates Birds Eukaryotic Cell Bony Skeleton Four Limbs Hair Eggs with Shells Official Business Step 2: Mark the characters/traits that fit the organisms. Sharks Goldfishes Frogs Primates Birds Eukaryotic Cell / / / / / Bony Skeleton X / / / / Four Limbs X X / / / Hair X X X / X Eggs with Shells X X X X / Official Business Step 3: Determine the Ancestral Character. Sharks Goldfishes Frogs Primates Birds Eukaryotic Cell / / / / / Bony Skeleton X / / / / Four Limbs X X / / / Hair X X X / X Eggs with Shells X X X X / Official Business Step 4: Identify the derived traits. Sharks Goldfishes Frogs Primates Birds Eukaryotic Cell / / / / / Bony Skeleton X / / / / Four Limbs X X / / / Hair X X X / X Eggs with Shells X X X X / Official Business Step 5: Draw the cladogram. Eggs with Shells Hair Four Limbs Bony Skeleton Eukaryotic cell Official Business Learning Checkpoint (Exercise) Official Business Exercise: Draw a cladogram using the following data: ORGANISMS CHARACTERS/TRAITS Lancelet Cell Goldfish Jaws Lizard Lungs Dog Nails Chimpanzee Fur Official Business dogs Exercise Key: chimpanzee cell jaws lungs nails fur fur lizard (derived trait) lancelet / x x x x nails (derived trait) goldfish / / x x x goldfish lungs (derived trait) lizard / / / / x jaws lancelet (derived trait) dogs / / / / / chimpanzee / / / / / cells (ancestral character) Official Business Taxonomy DESCRIPTION list of features or attributes of a certain taxon associating an unknown organism or taxon IDENTIFICATION with a known one formal means of naming organisms NOMENCLATURE binominal nomenclature CLASSIFICATION ordered grouping of organisms Official Business Taxonomy: Linnaean Classification System Carl Linnaeus Swedish Biologist Father of Taxonomy developed a hierarchical system of classifying life’s diversity based on anatomy and morphology Official Business Taxonomy: Linnaean Classification System Official Business Taxonomy: Linnaean Classification System Official Business Taxonomy: Linnaean Classification System Three Domain System of Classification Archaea Bacteria Eukarya Official Business Taxonomy: Linnaean Classification System Kingdom Classification System Official Business