BIO 115

- Theory of organic progression -> Transformation of species

- First coherent theory of evolution

- Species originate out of nothing -> spontaneous creation

- Lamarckism -> Inheritance of acquired characteristics

- Species differ because of different needs -> nervous fluid in organs triggers growth e.g. neck of giraffes

- Variational evolution

- Explorer ship -> mocking birds are diffrent on different islands

- Different lineages from single ancestor

- Evolution is not goal-oriented

- Descent with modification -> ancestor

- Natural selection -> survival of the fittest (struggle of life)

Lamarck: Transformational evolution -> e.g. all giraffes developped longer necks to be better adapted

Darwin: Variational evolution -> there is variation in the neck length of giraffes and those who were best adapted produced better adapted offspring (Natural selection)

- Characteristics of organsisms change over time

- Common descent

- Gradualism -> incremental evolution, evolution does not happen over night

- Populational change -> Change in proportions of individuals that have different characteristics

- Natural selection -> Ability to survive and reproduce as a result of changes in adaptions

- History of events by which taxa have originated from common ancestor

- Describes the history of species, gene families, tumors, cell lineages, languages and DNA sequences

- Each branch point (node) is division of ancestral lineage

- Humans and great apes are cousins (we did not descend from apes)

- Phenotypic similarity is not the same as phylogenetic similarity

- Example: Crocodiles and birds share a more recent ancestor but look very different as birds underwent more evolutionary changes than crocodiles

- Demonstrates which tree of phylogeny is the likeliest

- Tree that takes the fewest evolutionary changes is the most likeliest

- Joining of separate lineages into one e.g. hybridization -> genes have moved horizontally between organsims

- Analysis of the mitchondrial DNA (mtDNA) -> inherited only by the mother (maternal inheritance) -> female history -> common ancstor in woman in Africa (120kya)

- Coalescence analysis -> looking for haploid markers -> all variants coaelsce (unite) in one lineage

- In Africa

- genetic split much deeper in most Africans compared to non-Africans

- Most recent common ancestor -> 120kya

- Homologous characteristics: traits among species that are derived from a common ancestor (with or without evolutionary change) e.g. four limbs in vertebrates

- Analogous: Changes to the structure/function of these traits e.g. development of wings

- Traits/Characteristics that look very similar but work differently e.g. eyes of vertebrates -> structurally different

- Characteristic/trait that was developped independently from each other e.g. tasmanian tiger and wolve

- Homoplasy includes convergent evolution

- Result of similar adaptions in different lineages

- Numerous related lineages arises in short-time e.g. beaks of birds vary in shape and function -> the different beaks are highly adapted to food sources

- Adaption to different habitats

- Most common pattern of long-term evolution

- Evolution is the result of accumulated small changes over a long period of time -> couldn't convince people to believe in his theory (1800 steps for a 1%)

- Blending inheritance and selection would deplete variations -> natural selection can't continue

- Characteristics of offspring are an average of the characteristics of their parents

- Each parent provides a hereditary substance that mixes (blends)

- With blending inheritance -> there is no variaton in offspring of two parents -> all F1 are equal

- isolated two variants of the common garden pea -> yellow and green

- offspring in F1 was all yellow -> F2 was 1/4 green -> blending inheritance not true

- Ordinary cell division -> creates two copies of the chromosome (diploid)

- Special cell division -> creates haploid gametes (only one copy of chromosome)

- Paternal and maternal gamete form a zygote

- homozygous parents created heterozygrous offspring -> the allele of one parent is dominant / the allele of one parent is recessive compared to the one of the other parent -> heterozygous genotype but phenotype is the same in F1

- 3:1 ratio in phenotypes in F2

- 1:2:1 ration in genotypes in F2

- if allele frequencies doe not change over time -> population is in Hardy-Weinberg equilibrium and would stay there forever

- If not -> evolutionary forces might be at work e.g. natural selection, drift etc.

- Genes that are not on the same chromosome segragate independently

- If genes on same chromosome -> during meiosis recombination can occur when chromosomes overlap -> gametes are recombined with information from both chromosomes

- the furhter the distance between two genes the likelier the recombination -> recombination rate r (maximized at 0.5)

- Two loci are found inherited together more than expected by chance

- changes in genetic information after DNA replication

- Germ line: inherited; Soma: non-inherited

- Point mutations: SNP

- Structural mutations: Deletions, Insertions, Inversions, Translocations

- Genome duplication

- During DNA replication

- mutation rate humans: 10**(-8) -> around 30 mutations every time a gamete is made

- Contain regulatory sequences -> enhancers and silencers

- Promoter region -> initiation of transcription

- Exons -> actual coding sequence

- Introns -> buffer against mutations (get spliced out)

- Termination region -> transcription is terminated

- redundant -> multiple codons specify the same amino acid

- unambiguous -> no codon specifies more than one amino acid

- ancient -> same code in all organsims

- Single mutation (SNP) affects multiple traits e.g. Achondroplasia "dwarfism"

- All mutations that have phenotypic effects show pleiotropy

- Number of offspring an individual leaves to the next generation

- most mutations do not influence the fitness

- if they do -> they are deleterious -> bad for the fitness

- rarely benefical mutations that might spread by natural selection

- Industrial melanism -> melanic mutaton of moth -> became black during the peak years of the industrial revolution -> declined again from the 1960s onwards as pollution reduced

- mutant cockroach type developed a bitter receptor towards sugar/glucose -> hence they avoided the traps

- if humans select artificially by traits -> rapid evolution

- three strains of chicken -> average weight of 56 day old chicken is more than 4-fold