- Darwin learned from Thomas Malthus that competition exists
- New variation in pop. =
- recombination of chromosomes (meiosis)
- population level migration (gene flow)
- DOES NOT PRODUCE new genetic variants
- NEW genetic variation = MUTATION in DNA
Mutations affecting developmental processes = Evo. important
- purifying selection on both = no language development
- produces enough healthy to compensate for sickled cells
- plasmodium parasite causes O2 levels to drop = cell sickles
- sickled cells are removed with parasite
- i.e. virogene in monkeys transferred to cat lineage leading to 6 species 5-10 mya = cross infection
Retrovirus = reverse transcriptase = DNA from RNA =inserts into genome (mostly non-functional/detrimental)
- rapid, intense, directional
- recurrent event
- i.e. G. magnirostris is 50% larger that G. fortis
- 20 selective events needed to transform morphology in 200 yrs.
- Oscillating selection prevents it
- larger bills = make mRNA earlier and more
- activation of BMP4 may vary btwn species and within = ?
Regulatory genes = how much BMP4 is expressed = variation seen (NOT BMP4 itself)
- lots of time and energy to develop
- width and depth are genetically correlated
- same genes/linked genes are involved
- large change within generation
- only some heritable = smaller change between generations
- don't hybridize OR offspring not fertile
- many species can't be tested (extinct)
- Doesn't apply to asexual taxa
- difficult to apply to divergent populations that hybridize regularly
- available only for limited #,
- different phylogenies produced depending on characters measured
- small genetic differences counted (may be irrelevant to breeding) = specie overestimation
- polymorphic morphology (i.e. grasshopper color morphs, salmon)
- cryptic species = repro. isolated, but differ in attributes (NOT morphology) (i.e. pipistrelle bats = different ecological life styles
- DNA barcoding used to I.D.
- sequenced genome CO1 in mitochondrial DNA
- Similar IN species, Different BETWEEN
- GOOD = need physical identity of specimen but don't have to kill them
- Skipper butterflies (Costa Rica)
original thought = variations of 1 species
Today = 1 split into 4 species
- (2) feed on grasses & (2) feed on palms = ecologically very different
- species contaminated with hybridization?
- mtDNA & Nuclear microsatellites = red wolves = coyote and grey hybrid
- Is it worth saving? Maybe niche occupied is?
- each species = Linnean name = genus & species
- Each = type specimen in collection
- Consult I. Code of Zoo. Nomen.
- Authorship= author's name and date of pub. given after name= ( ) for original author if name change
- Anonymous pub. = not valid
- different flowering times = assortative mating bc = timing and success in soil
- major host = hawthorns
- 150 yrs ago= recorded best of apples = first time
IF ALLOPATRIC SPEC. = gold forms between lakes = closest relatives (same for blue)
New dietary niche = higher frequency = allows feeding on smaller prey
- pattern has arisen in multiple places (Australia, Borneo)
- tend to have long constant frequencies
- most energy into 2nd harmonic
- character displacement = one form better to one environment= selection occurs
- to avoid competition = 2nd invasion evolved different type
evo. of body form is adaptive (habitat use)
- when host changed = bacteria changed
GOOD EVIDENCE = parasite evolves (better egg mimicry) to host defences & host evolves to trickery (rejection of mimics)
- selection for host defense = related to chance of infect. per clutch raised
i.e. Barbastelle bat
- DNA barcoding = calls 10-100x fainter (stealth) that other air feeders = detects moths before response
- costs = can't locate long range prey
- Laurasia to north
- Gondwanaland to south
- fossils of same Triassic reptiles found in continents joined in Gond.
- Southern beeches found in Chile & New Zea.
- Flightless ratite birds in S. Amer. (rheas), Africa (ostrich), Australia (emu, cassowaries = adapt. rad.), New Zea. (kiwi) = common ancestor in Gond.
- can check molecular phylogen. of mamm. w/ geo. time
- i.e. elephant shrews + elephants
- TODAY = only in north Scandinavia
120,000 ya (warmer) = continental species (Oodes gracilis) = found in Britain
- TODAY = continental Europe
= changes in distribution = clues about past climate
= evo. History of group (where taxa came from)
Outgroup = possesses no derived characteristics
Root of tree = ancient time
Nodes = give way to branches
Sister taxa =branch back to same node
*physiology + structural characteristics = don?t reveal group as are on trees
= can?t tell what branching order is (more than two branches from node)
= group includes most recent common ancestor of group and ALL descendants
i.e. primates all date to same common ancestor
Does NOT contain the most recent common ancestor of all members and all decedants
Phylogenetic reconstruction: physical characters used
Phylogenetic reconstruction: molecular characters used
- slow developing DNA = no good between mammals
- too quick = can?t recognize timing of characters
- Inherited maternally = single unit
- Evolves rapidly/constant rate
Phylogenetic reconstruction: Molecular Characters
= large # of taxa = DOESN?T carefully look at all trees
= quick evaluation = what is most probable
doesn?t guarantee best tree = high chance though
= random sampling data over & over = make tree= do they agree?
Scaling branch lengths for time
- i.e. rRNA from microscopic algae ( (E. huxleyi & C. pelagicus)
- diverged 65 mya
differ = 5% nucleotides
divergence rate = 5/65 = .08% per mill. Yrs
= ok to apply rate to eco. Similar taxa w/out fossils
- oldest rocks = 3.8 bya
- early atmosphere = little Oxy.
3.5 bya= first fossil evidence of life.
- Stanley Miller (53) = electrical discharges into CH4, NH3, water = amino acids = formaldehyde + hydrogen cyanide prod. = further rxn = nucleotides = accumulate in pre-biotic soup
TODAY= early atmosphere = CO2 and nitrogen = less conducive
- Still able to produce amino acids away from Millers conditions
- evo. sex. repro. (allows recombo)
- Evo. organelles (compartmentalization of processes)
- 435-370 my old 'ostracoderm' = jawless vertebrates = China & Vietnam = GOES BACK earlier than initially thought
- Putative fossil embryos = bilateral anim., arthropods, flatworms = before Edicaran fauna
CAUSES = climate/ glaciation @ south pole
PHASE 1: stagnant + changes in sulphur in water affect benthic nektonic/ planktonic sp.
PHASE 2: anoxic water onto continental shelves = extinction in shallower habitats
- sponges, corals, = suffered
- deep water sponges/trilobites = OK
Series of Pulses: Causes = controversial
- Global oceanic anoxia (no O2) = Evid. = global distrib. of black shale
- Global cooling
- asteroid/comet impact (6 of 10 today from then)
- periodic bombardment (asteroids, meteors)
- no astrophysical explanation
- only evidence = K-T & end-Devon.
- rates & dates may not be sound
- some = result of two independ. events
- similarity @ MHC loci = increasing rates of infertility/miscarriage
- confirmed in 2004
- maternal relatives of homosex = >fecundity than maternal relatives of heterosex.
- fits w/ X-linked genetics
- accounts for 14% of homosex.
- chance of rearing baby from birth to independence declines
- risks to mother and offspring increases
- her own daughter will start repro.
E.D. Wilson (70s) = relationship between social behaviour and evo.
- could be related to low levels of chorionic gonadotrophin in absence of preg. sickness = causes risk of miscarriage
*expect to see pop. in malaria affect areas = NOT in HWE = more heterozygotes than expected
- molec. variations accumulate over time
- to see divergence of species = look at # of sequence differences
most mutations = silent and don't affect amino acid sequence
- increases freq. of homozyg./decreases hetero. as expected w/ HWE
- exposes deleterious alleles to select. = Inbreeding Depression
- inbreeding coefficient = F = probability of two homologous alleles being identeical by descent
- if you have one recessive/one dominant = less chance of another recessive if outbreed (cultures w/out = high genet. disease
- changes genotype freq. but not allele freq.
- mechan. to avoid = dispersal, mate choice, etc.
- i.e. inbred song sparrows = less likely to survive pop. crash