Bio 2970 Larson

-founder of geology
-author of principle of geology
-uniformitarianism

o 1. Uniformity of law – laws of physics and chemistry have been constant through earth’s history
• methodological assumption
o 2. – use familiar geological processes to explain past events
• methodological assumption
o 3. Gradualism – geological change occurs in small increments, which accumulate through time to produce large changes
• a testable hypothesis
o 4. Non-directionalism – dynamic steady state; the more things change, the more they stay the same
• a testable hypothesis

-proposed impact crises hypothesis in 1980s

-proposed by walter alvarez
-stated that sudden impact of major asteroid caused devastation to the earth approximately 65 mya caused mass extinction as well
-hypothesis rejected gradualism

-darwin's bulldog
-agnostic
-criticized religion/was very anti-creationism
-responded to darwin with active doubt

-rational explanation based on measurable natural phenomena
-theory must be potentially falsifiable
-must make empirical predictions

-the simplest hypothesis is the working hypothesis

-bohr
• subjective (volitional) aspects of measurement – concepts formed measurement chosen
• objective (cognition) – measurements as properties of the systems being studied

-"active doubt"
• Potential falsification of working hypothesis with data

- organisms during their lifetime by willing or wanting characteristics to occur which then modify the hereditary and be passed on to the next generation
o Use and disuse of parts influenced their hereditary
o “inheritance of acquired characters”

- Darwinism minus Lamarkianism inheritance

- Darwinism + mendelism + chromosomal theory of inheritance

- perpetual change with continuity from past to present life
- life has a long history of change

- variation among organisms = basis for evolution
- organisms do not erode

- all our plants and animals have descended from some one form into which life was first breathed

series of ancestor-descent populations

1. persist without change
2. persist with change
3. branch - bifurcate
4. go extinct

separate lineages accumulate differences from their common ancestor and from each other

ontogeny recapitulates phylogeny

development of an organism from zygote to adult

embryos pass through the adult forms of ancestors

- part of Haekel's biogenetic law
- states that new characters are added to the end of an ontogeny

- part of haekel's biogenetic law
- states that older features displaced to earlier and shorter developmental occurrences

-exception to recapitulation
-evolution of new characters restricted to pre-adult stages

evolutionary change in developmental rates and timing

evolutionary change in the physical location of a developmental process within the body

the structure of evolutionary history is a branching tree of lineages

the same organ in different organisms under every variety of form and function

forms derived from an equivalent characteristic of a common evolutionary ancestor

a nested hierarchy of groups within groups
- mammels
- birds

- a group of two or more species/lineages that includes the most recent common ancestor of all members of the group and all of its descendants
- diagnosed by sharing homologies

shared derived character

character similarity that does not represent common ancestry

-lineages diverge from their common ancestor but not from each other
- similar mutational or developmental processes used

-evolutionary return to an ancestral character

origin of superficially similar features by dissimilar evolutionary processes

-Ernst Mayr
-DEFINITION OF A SPECIES: a reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature

set of resources actually or potentially used by a population (ecological definition)

geographic barrier that isolated two populations so that they evolve separately and there is divergence in ways that make them incapable of reproducing together

-prevents fertilization of egg and sperm from different species
types of barriers:
-temporal (reproducing at different times of year)
-ecological barriers
-behavioral barriers
-mechanical barriers
-gametic barriers

still capable of mating but there are problems relating to the development or fertility of the hybrid outcomes
-hybrid inviability
-hybrid sterility
-hybrid breakdown

fertilization occurs, zygote produced, but in the development of the zygote in the embryotic stages there is an inviability so that the hybrids are not produced

hybrid individual reproduced, but hybrids are not capable of producing fertile sperm or eggs and cannot propagate themselves
- ex: mule

hybrids produced and are fertile but when you mate the hybrids with each other you get offspring that are deficient in some way

1. pertains to sexual forms only
2. no temporal dimension
3. not a single unit of evolution
4. often not practically testable

a species is a lineage of ancestral-descendant populations diagnosably distinct from other such lineages

geographical isolation of populatoins proceeds evolution of species-level evolutions

subdividing a formerly continuous habitat
- ex: sea urchins across the Isthmus of Panama

rare dispersal across a pre-existing barrier
-ex: newly founded bird populations on different Galapagos Islands

-sympatric speciation
-splitting of species to form a different species in a single geographic location

-evolutionary change occurs only in small increments, never in jumps

large phenotypic change in one step

characteristic pattern of gene expression and development

offspring resemble their parents more closely than they do individuals picked at random from the population

a trait that evolved by natural selection for a particular biological role

a trait co-opted by natural selection for a role incidental to a trait's origin
-ex: illustrated by utility of bird's feathers for flight

all copies of homogoous DNA trace back to a common ancestral molecule

identify the essential aspects of reality and remove distracting elements

fate of alternative forms of genes or gene combinations over space and time in a reproducing population

branches show descent of copies of homologous DNA

branches denote mutational events in evolution of homologous DNA

set of identical haploid genomes for a specified unit of measurement

-single nucleotide polymorphisms
-a DNA sequence variation occurring when a single nucleotide in the genome differs between members of a biological species or paired chromosomes in an individual

a local population of reproducing individuals that has physical continuity over space and time

-population of gene copies collectively shared by individuals of a deme
-population of potential gametes that can be produced by the individuals of the deme

-alleles A and a have equal frequencies
-offspring are 1/2aa and 1/2AA
-ex: self-fertilizing plants

-alleles A and a have equal frequencies
-offspring are 1/4AA 1/2Aa 1/4aa
-mendelian ratios observed

p^2 + 2pq + q^2 = 1

-p = allele frequency of A
-q = allele frequency of a

1. Infinite population size
2. No natural selection
3. No migration among demes
4. Random mating

analysis of genetic variance for continuously varying phenotypes within a population

set of phenotypes associated with a particular genotype in interaction with a variety of environmental conditions and genetic backgrounds

-average or expected value of x
-measures where the distribution is centered

-measure of how far an individual spreads out from the mean
-equation: sum(x-xbar)^2/n
x = sample value
xbar = mean value for popution
n = number of members of population

-measure of spread of a distribution
-sqrt(variance)
-has same units as mean

portion of variance associated with genetic differences between different loci

how much of phenotypic variation is attributed to genetic variation

the proportion of phenotypic variation attributed to additive genetic variance

average genotypic deviation caused by a gamete bearing allele "i" after fertilization by a second gamete drawn at random from the gene pool

-measures the influence of a diploid genotype on phenotypic variation in the next generation
- = the sum of the average excesses of both gametes born by genotype

-the genetic variation that results from additive effects of alleles
-the average of the squared breeding values for all individuals in the population

-locus whose variation contributes to populational variation of a continuously varying phenotype

saturated, genome-wide linkage mapping, SNP markers every 10 cM throughout genome

use haplotype tree to test SNP sites for influence on disease phenotype

- nonadditive variance associated with epistasis at the population level
- genetic epistasis is necessary but not sufficient for epistatic variance

- factors or processes that can change the frequency of an allele in the gene pool
1. mutation
2. genetic drift

random changes caused by finite population size

the size of an ideal population whose rate of random genetic drift equals that of the real population

the size of an ideal population having the same rate of accumulation of identity of identity by descent as the population being studied

large population subdivided into many demes

movement of genes between demes