Biologie für Geologen Gerard Versteegh Karin Zonneveld Zentrale Themas • Leben • Evolution • Ökologie • Zusammenhänge • Fragen I Leben beinhaltet..... • Organisation • Fortpflanzung • Wachstum und Entwicklung • Energieverbrauch • Homeostase (Selbstinstandhaltung) • Evolutionäre Anpassung • Wechselwirkung mit Umwelt Ökologie studiert.... • Wechselwirkung von Lebewesen zwischen einander und mit der Umwelt Evolution ist.... • Genetische veränderung ? Evolutionstheorie • was ist eine wissenschaftliche Theorie ? Wissenschaftliche Methode Wahrnehmung Frage sehr oft Hypothese - Vorhersage Experiment + Wahrnehmung Evolutionstheorie • sehr oft bestätigte Hypothese • Wahrnehmungen: Vergleichende Anatomie • Morphologie • Embryologie Fossilien Biogeographie Taxonomie und Systematiek Co-evolution http://waynesword.palomar.edu/pljune99.htm#thicket http://waynesword.palomar.edu/pljune99.htm#thicket Style length in figs varies Female fig-wasps enter the fig with female flowers ripe through the ostiole They pollinate the female flowers They lay eggs in the short-style ovaries by putting the ovipositor through the style Ovipositor is too short for the long-style flowers to reach Fig and fig wasp-larvae develop simultaneously. Male emerges just before male flowers open Male fertilises female Male activity increases CO2 in fig Males eat themselves out CO2 level drops Females become active Male flowers are ripe Females collect pollen Females escape Female enters new fig flower with ripe female flowers Female flowers become pollinated..... Weiblen and Busch, 2002. Mol. Ecol. 11:1573-1578 Fig. 2 Evolutionary patterns of host association in pollinating mutualists and nonpollinating parasites of Ficus subgenus Sycomorus sensu lato. Species associations between pollinating Ceratosolen and Sycomorus are pairwise, in contrast to Apocryptophagus, where multiple unnamed parasite species may attack a single host species and some host species are not attacked at all. Cospeciating nodes inferred from reconciled trees are marked by dots. Bootstrap percentages > 50% based on 1000 replicates are listed below the nodes. Phylogenies are based on parsimony analyses of nuclear ribosomal ITS sequences for Ficus and mitochondrial COI sequences for fig wasps. (a–h) refer to species pairs in Fig. 3. Fig-wasp nematodes in Panama................ ..........each wasp species has its nematode species Weiblen and Busch, 2002. Mol. Ecol. 11:1573-1578 Moderne Beispiele DNS Analyse MRSA - Methicillin Resistant Staphylococcus aureus Evolution of a unique Plasmodium falciparum chloroquine-resistance phenotype in association with pfcrt polymorphism in Papua New Guinea and South America Anti-HIV Antibodies Influence HIV Evolution Clinical evolution of multidrug-resistant tuberculosis in Tijuana, Baja California Evolutionstheorie • 1831 Patrick Matthew • On naval timber and arboculture • 18 June 1858: Linnean Society: • Charles Darwin • On the Perpetuation of Varieties and Species by Natural Means of Selection • Alfred Russell Wallace • On the Tendency of Species to form Varieties Darwins Buch • 24 November 1859: On the origin of Species... Modern Thinker Buffon Father of Genetics Systema Naturae Georg Mendel 14-July-1789: French revolution Carolus Linnaeus Continental Drift 04-July-1776: USA Independence Pre-Darwinian Evolutionist Alfred Wegener 1861-1865: USA Civil War Erasmus Darwin Non-Darwinian Evolutionist Jean B. Lamarck Inspired Darwin Thomas Malthus Hopeful Monsters Father of Comparative Anatomy Richard Goldschmidt Georges Cuvier Unity of Type Geoffry St.-Hilaire Darwins Mentor Adam Sedgwick Father of Modern Geology Charles Lyell Archetypes Richard Owen Father of Glaciology “The Modern Synthesis Louis Agassiz Julian Huxley Shifting Balance Theory Sewal Wright Population Genetics Ronald Fischer Non-Darwinians Population Genetics Darwinians J.B.S. Haldane Genetics Neo-Darwinians Natural Selection Theodosius Dobzhansky Charles Darwin German Synthesis Bernhard Rensch Somatic Mutation Theory August Weismann Co-Discoverer Natural Selection A. Russel Wallace Paleontology G.G. Simpson Co-Discoverer Natural Selection Systematics Ernst Mayr Patrick Matthew Botany Darwins “Bulldog” G. Ledyard Stebbins Thomas Huxley “Ontogeny Recapitulates Phylogeny” Ernst Haeckel Scopes Trial Origin of Species W.W.1 W.W.2 1700 1750 1800 1850 1900 1950 2000 Evolutionstheorie (VIST): • Variation: • All life forms vary genetically within a population. It is this genetic variation upon which selection works. • Inheritance (Vererbung) • Genetic traits are inherited from parents and are passed on to offspring. • Selection • Organisms with traits that are favorable to their survival get to live and pass on their genes to the next generation. • Time • Evolution takes time. Evolution can happen in a few generations, but major change, such as speciation, often takes long periods of time. Evolutionstheorie (Mayr) • Natural selection is the differential reproductive success of individuals. • Operates through interaction between environment and populations variability • Results in adaptation of a population to its environment. Operates on the phenotype but functions via the genotype only Evolutionstheorie • Inheritance - Vererbung Vererbung und Variation Prior to Georg Mendel: blending theory of inheritance: Problem? maintenance of variation Georg Mendel (1866) - Particles of inheritance - are present in pairs in breeding adults - separate in gametes so that each gamete has only one of each pair - occur as dominant an recessive forms. Wilhelm Johannsen (1857-1927) call these particles genes (defines: genotype phenotype) Phenotype - Genotype • Nicht alle Variation ist Vererbbar • Genotype: individuelle genetische Zusammensetzung • Phenotype: Erscheinungsbild des Individuums The double helix mRNA=messengerRNA tRNA=transferRNA http://www.accessexcellence.org/AB/GG/#Anchor-From-14210 Evolutionstheorie Variation • ist alle Variation evolutionär relevant ? • Wo kommt die Variation her ? • Fragen II Phenotype - Genotype • Nicht alle Variation ist Vererbbar • Genotype: individuelle genetische Zusammensetzung • Phenotype: Erscheinungsbild des Individuums • Nur vererbbare Variation evolutionär relevant? Point mutations Point mutations Larger mutations Mutation • Trisomy • Polyploidy The condition in which the number of chromosome sets in an individual or cell is three or more times the haploid set; 3n, 4n, etc. About half of angiosperm (flowering plant) species seem to have originated this way. Relatively few animal species are thought to have originated this way, because not all animals can self-fertilise or reproduce asexually. However, brine shrimp, weevils, bagworm moths and flies seem to have arisen this way. Mutationen • Relation zur Vererbung • Relation zur Umwelt • Gewünschte Mutationen Randomness of mutation • Desired mutant cannot arise in response to environment • May be cryptic: e.g. not every amino acid is equally sensitive to mutation. • Mutations may affect germ-cell fitness • NB: Evolution is not random ! Randomness of mutation • Will selectively neutral mutations spread in the population ? allele frequencies tend to stabilise at the equilibrium between forth and back mutation rates Mutation rates • Per base pair per replication 1 x 10-9 • per gene per cell generation 1 x 10-5 to -6 • Low at individual level • 4 x 109 Humans: 80.000 with a new mutation • chromosomal mutation 10-3 to -4 per gamete per generation • Rates vastly different between genes and taxa Mutation frequencies: p.105 Evol. Mutation impact • Most mutations are phenotypically neutral • Why are phenotypically expressed mutations more likely to be deleterious ? • Is this also true for mutations in general ? Evolution • Wann gibt es keine Evolution? Hardy and Weinberg No evolution if: 1. Mutation is not occurring 2. Natural selection is not occurring 3. The population is infinitely large 4. All individuals of the population breed 5. all mating is totally random 6. everyone produces the same number of offspring 7. there is no migration in or out of the population Is this feasible to occur ? Evolution Non selective: inbreeding - effective population size Ne genetic drift - sampling error founder effect gene flow - migration mutation Natural selection: Hardy and Weinberg no evolution G gametes A a Freq. p q A p AA Aa E gametes p2 pq a q Aa aa pq q2 Genotype: AA Aa aa Frequency: p2 2pq q2 Equilibrium equation p² + 2pq + q² = 1 p = AA + ½Aa q = aa + ½Aa A= dominant a= recessive Does a dominant character tend to spread in a population ? Albinism Albinism is a rare genetically inherited trait that is only expressed in the phenotype of homozygous recessive individuals (aa). The average human frequency of albinism in North America is only about 1/20,000 Calculate the phenotype and genotype frequencies q² = frequency of homozygous recessive individuals (the albinos) = .00005 q = √1/20.000 =.007071 p + q = 1 (alle allele zusammen) p = 1- √1/20.000 = .9929 p² = frequency of homozygous dominant individuals = (1- √1/20.000)2 = .9859 2pq = frequency of heterozygous individuals = .01404 = (or 1 - (q² + p²) Inbreeding Mating with relatives (self fertilisation): homozygosity allele frequencies remain constant ! Aa Parent 1/4 AA 1/2 Aa 1/4 aa F1 3/8 AA 1/4 Aa 3/8 aa F2 1/2n Aa Fn What are the benefits of asexual reproduction ? Inbreeding depression Genetic drift Genetic drift Strong in small populations http://anthro.palomar.edu/synthetic/Default.htm Founder effect A genetic bottleneck - speciation.