Download phenotypically - geo.uni

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
Father of Genetics
Buffon
Systema Naturae
Georg Mendel
Carolus Linnaeus
Continental Drift
Pre-Darwinian Evolutionist
Alfred Wegener
Erasmus Darwin
Non-Darwinian Evolutionist
Jean B. Lamarck
Inspired Darwin
Hopeful Monsters
Thomas Malthus
Richard
Goldschmidt
Father of Comparative Anatomy
Georges Cuvier
Unity of Type
Geoffry St.-Hilaire
Darwins Mentor
Adam Sedgwick
Father of Modern Geology
Charles Lyell
Archetypes
Richard Owen
“The Modern Synthesis
Father of Glaciology
Julian Huxley
Louis Agassiz
Shifting Balance Theory
Sewal Wright
Population Genetics
Ronald Fischer
Population Genetics
Non-Darwinians
J.B.S. Haldane
Darwinians
Genetics
Neo-Darwinians
Theodosius Dobzhansky
Natural Selection
German Synthesis
Charles Darwin
Bernhard Rensch
Somatic Mutation Theory
August Weismann
Co-Discoverer Natural Selection
A. Russel Wallace
Paleontology
G.G. Simpson
Systematics
Co-Discoverer Natural Selection
Ernst Mayr
Patrick Matthew
Botany
G.
Ledyard Stebbins
Darwins “Bulldog”
Thomas Huxley
“Ontogeny Recapitulates Phylogeny”
Ernst Haeckel
Origin of Species
1700
1750
1800
1850
W.W.1
1900
14-July-1789: French revolution
04-July-1776: USA Independence
1861-1865: USA Civil War
Scopes Trial
W.W.2
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:
Natural selection:
inbreeding - effective population size Ne
genetic drift - sampling error
founder effect
gene flow - migration
mutation
Hardy and Weinberg
no evolution
G gametes
E gametes
A
a
Freq.
p
q
A
p
AA
p2
Aa
pq
a
q
Aa
pq
aa
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