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Bio 103 Evolution
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- 1Evolution:Darwin variation btwn breeding due to fitness. The accumulation of inherited changes in population overtime leading to evolution of natural selection theory
*some evolution is neutral - 2Darwinian Fitnessindividuals ability to survive and reproduce relative to other members of population
- 3Populationindividuals of one species in a geographic area sharing same gene pool (POPULATIONS EVOLVE; INDIVIDUALS DO NOT)
- 4communitygroup of species that live together and interact in the same area
- 5ecosysteminteractive system composed of one or more communities and their abiotic environment
- 6biosphereall earths ecosystems together
- 7Theory of Evolution and the 4 assumptions made1. variation in phenotype.
2 high reproductive potential
3. individuals compete for limited resources
4. more fit individuals with phenotypes matching environment more likely to survive and reproduce - 8Other assumptionsnatural selections acts on phenotypes within generations, but evolution acts btwn generations
- small evolutionary changes happen fast b complex take time - 9The evidence for evolution1. Fossil record
2. biogeoraphy ( flightless birds explained by Gondwana and break up)
3. selective breeding (ex: cabbage, broccoli, cauliflower, kale)
4. Convergent Evolution (homoplastic/analgous features - similar F in distant related organisms, - 10Homologies: 1. Anatomical 2. Developmental 3. Molecular- derived from the same structure in common ancestor.
1. vestigial structures: remnants of structures indicate adaptive wax and wane as environments change (homology in human vs. Cat).
2. reveals ancestral structures no longer present in adults (gills, are in human embryo suggest humans evolved from aquatic animals Ernst Haeckel).
3. heomeotic genes show universal body plan in animals, box genes dictate order of growth of diff. segments of body, and phylogenetic analysis show how similar homolous DNA sequences are - 11Proximate vs. Ultimateproximate: immediate observation, mechanistic
Ultimate: involves evolutionary perspective - 12Phenotypes:physical expression of genotype
- 13genotypecombination of alleles at a given locus on homologous chromosomes
- 14allelesvariants of DNA sequence at given locus
- 15Genetic Variation caused by?1. mutation: cannot enter population unless this occurs in gametes
2. sexual reproduction: recombination via crossing over in meiosis - 16Problems with sexAsexuality, clonal reproducing populations WIN FAST
ex: curt lively and the New Zealand snails: sexual reproduction is more common in habitats where parasitism is high by producing genetic variation in the population - 17Genetic polymorphism is maintained by :1. balance polymorphism (heterozygotes more fit than homozygote) ex: malaria; heterozygote carriers of sickle cell allele confer resistance to malaria, Ex 2: heterozygotes for cyclic fibrosis confer resistance to typhoid disease( tradeoff)
2. frequency dependent selection (fitness depends on relative abundance of morph) ex: land snails eaten by song thrushes, patterns are selected for in mosaic habitat, also neutrality (not being exposed to selection)
3. Spatial/temporal environmental variation ex: one genotype can produce diff phenotypes in diff env'ts ex: yarrow plants grown in common garden retain ecotype
4. environments also affect developing phenotypes of quantitative loci ~ norm of reaction: continuous range of phenotypic possibilities ex: human height. also heritability of quantitative traits, and morphological traits show quantitative genetic variation = multiple loci and env'tal effects - 18Populationgroup of interbreeding individuals, they can change in numbers, geographic locations, and genetic composition
- 19Polymorphismgenes in natural population are usually polymorphic.
Polymorphism: variation of traits ex: orchids can be red or yellow
Polymorphic gene: gene that exists as two or more alleles - 20Population Geneticsconcerned with allele and genotype frequencies
- 21Allele freqnumber of copies of a specific allele/ total number of alleles in that gene
- 22genotype frenumber of individuals with specific genotype / total number of individuals
- 23hardy-weinberg eq'nrelates allele and genotype frequencies in a population:
2 alleles in a pop: A and a
p= freq of allele, A, q= freq of allele a
p+q=1, AA=p^2, Aa=2pq, aa=q^2, p^2+ 2pq+q^2=1 - 24An Equilibrium Populationif allele frequencies can predict genotype frequencies using the HW eq'n then the population is considered to be at equilibrium
- 25Hardy Weinberg Conditions1. population is large
2. Random Mating
3. No Migration
4. No natural selection
5. No Mutation - 26microevolution and its mechanismschanges in population gene pool from generation to generation
MECHANISMS:
Natural selection, random genetic drift, migration, nonrandom mating - 27Sources of new genetic variationnew alleles, gene duplication, exon shuffling, horizontal gene transfer
- 28Reproductive success if measured in:1. characteristics that make organisms better adapted to env't and therefore more likely to survive and reproduce
2. individuals produce viable offspring (mean fitness) - 29mean fitness of the popaverage reproductive successor members of a population
- 30Different patterns of natural selection: Directional selectionfavours individuals in one of the other two extreme phenotypes
- 31Patterns of natural selection: Stabilizing selectionfavours intermediate phenotype
- 32Natural selection patterns: disruptive selectionfavours the extreme phenotypes
- 33Natural selection patterns: Balancing selectionmaintains genetic diversity in a population, which can occur as a result of : heterozygote advantage ex: malaria, or negative freq- dependent selection: more common individuals less fit, ex : orchids
- 34Allopatric speciationgene flow is interrupted when a population is divided into geographically isolated subpopulations
( a population forms a new species while geographically isolated rom its parent population) - 35sympatric speciationa subset of population forms a new species without geographic separation
- 36sexual selectiona type of natural selection that directive promotes reproductive success
- 37Intrasexual selection Intersexual selectionIntra: between members of the same sex: Ex: enlarges claw of male fiddler crab, males defend females from other males
Inter: between members of opposite sex ex: peacock feathers more extravagant than peahen's - 38Random Genetic Driftin small pops, allele freq can be altered by random genetic drift
DRIFT: random sampling error, and over time, it favours either loss or fixation of an allele ( 0% or 100%) - 39Bottleneck effectlarge population subject to dramatic decrease in size, remaining individuals repopulate but genetic variation significantly lower than it was before
- 40Founder Effectsmall groups of individuals move to new location, their allele frequencies are expected to be significantly different from original population by chance
- 41Kimura's Neurtral theory of evolution- genetic drift plays in important role in promoting genetic change: neutral variation does not favour any genotype
- most genetic variation is due to the neutral mutations that have attained high freq in a population - 42Gene Flow- occurs in result to migration, its when individuals migrate between populations with different gene freq
- 43Non- random mating- affects the relative proportion of homozygotes and heterozygous in a population
- 44positive assortative matingchoose mates with similar phenotype, this tends to increase freq of homozygotes
- individuals may choose to demand on another's past history is they want to avoid inbreeding - 45Inbreeding depressionsproduces homozygous that are less fit
(deleterious recessive genes exposed to selection) - 46Mating systems: Intersexual selectionmales compete with one another
ex 1: hangingflies present females with nuptial gift, the bigger the gift the more likely she will mate with him
ex 2: handicap principle in widow birds, females like males with longer tails, may indicate good genes - 47Mating systems: Intrasexual selectionfemales actively elect best males
ex: elephant seals compete to defend their female harems - 48Monogamous mating systemMales and females are paired for at least one reproductive season
M & F are generally more similar in size and appearance - 49Mate guarding hypothesisexplains monogamy:
males stay wit females to prevent their being fertilized by another male - 50Male assistance hypothesis:explains monogamy by: males remain with females to help her rear offspring
- 51Female - enforced monogamy hypothesis:explains monogamy:
females stop males from being polygynous - 52polygnous mating systemsone male mates with many females
- 53resource based polygny:is a polygons mating system:
some males dominate resources and mate with more than one visiting female - 54Harem mating structuresis a polygnous mating system: where males defend group of females without commanding recourse based territory
- 55communal courting (i.e. leks)polygynous mating systems:
males all congregate to perform mating display, females choose best mate - 56Polyandrous mating systemone female mates with many males
- role reversal seen
- females productivity is high, she is only limited by number f males she can find to incubate eggs - 57Speciation:when reproductive isolation leads to the formation of a new species
- cessation of genetic exchange between populations lead to divergence and evolutionary alterations - 58sexual selectionwhen certain traits or characteristics are favoured by evolution due to their appeal to the opposite sex
- (sometimes contradict natural election)
ex: male peacock feathers make it harder to escape predators
( passing genes on is determined by ability to survive and ability to get oneself into position to pass on gene) - 59Every male will get the chance to "sow its seed"ex: large portion of elephant seal males die without conceiving
- 60Dimorphismsexual selection leads to dimorphism between sexes
- males differ in appearance to females, bc some characteristics in males make them more likely for sexual selection ex: male widow birds possess long tails, while females do not- longer the tale, the more likely it is that the male will "get lucky" - 61Reproductive isolating mechanismsprocesses that prevent the production of offspring from members of different species, these act as barriers between species that prevent the flow of genes, which allows for the separation of organisms into diff. species
- 62Prezygotic barriersmultiple barriers that prevent mating or fertilization
- 63habitat isolationA prezygotic barrier
- isolates into different geographic areas, prefers for different habitat types - 64temporal isolationa prezygotic barrier
- differences with mating season
- differences with time of activity (nocturnal vs. day lovers) - 65behavioural isolationa pre zygotic barrier
-required mating rituals, scents, calls
ex: male satin bowerbirds build bowers of twigs, using bright blue in order to attract females - 66mechanical isolationprezygotic barrier
-genital organs are not compatible ex: certain flowers can only be pollinated by small needs, while other flowers can only give pollen to larger bees - 67gametic isolationegg and sperm do not recognize each other due to differences in molecular recognition signals
- 68postzygotic barriersinterruptions that occur after fertilization
- 69hybrid inviabilitya post zygotic barrier
-embryo dies before birth due to genet issues - 70hybrid sterilitya postzygotic barrier
-embryo lives but the offspring is unable to reproduce, therefore preventing the line from continuing
- issues with meiosis produce inviable gametes - 71Horses and Donkeys; applied to post zygotic barriersmules are offspring where the father is a donkey and the mother is a horse
- tends to be larger and easier to succeed at breeding
- hinnys are offspring where the mother is a donkey and the father's a horse - 72Allopatric Speciationgeographic barriers isolate pop into 2 or more groups over time and develop a new species (most common form of speciation. Ex: isthmus of panama separated two populations of the same species of fish 3.5 million years ago. They are now different species.
- 73genetic driftrandom mutations and alterations to allele frequency within a population that occur by chance and are passed on btwn generations, which lead to the differentiation of populations that have limited access to each other
- 74Sympatric speciationdifferentiation that occurs within a population without geographic isolation
- caused by major genetic changes that quickly make reproductive isolations
- changes in the number of sets of chromosomes can cause sympatric speciation. - 75polypoid:a change in the number of sets of chromosomes that cause sympatric speciation
- this is an organism with more sets than 2 : due to non disjunction or other issues during meiosis, also occurs withins a species - 76allopolyploida change in the number of sets of chromosome that cause sympatric speciation
- this is an organism that creatures multiple sets of chromosomes from multiple species
ex: wheat (most likely happens in plants than animals bc they can handle more genetic changes) - 77Adaptive radiation- the differentiation of a single species into a multitude of different species
-due to adaptations to a new environmental feature or a new physiological feature
ex: the adaptive radiation f cichlid fish since the previously dry lake victoria became wet again - 78Taxonomyinvolves integration of organisms into categories or taxa
- each taxa has an associated name, common phenotypic traits that go into categories
- this is useful for providing animals with unique names, identifying and, showing historical relationships btwn organisms - 79hierarchy of taxonomyseries of classifications starting at the broad and vague ------- then to specific
all based on observation: domain, kingdom, phylum, class, order, family, genus, species, sub species/ polymorphic variants - 80binomial nomenclaturethe accepted form for scientifically titling an organism, developed by Linnaeus
- provides the genus and species name in the following Genus species ( in italics, genus is capitalized), also written in latin - 81evolutionary phylogenytracks the development and differentiation of organisms from a common ancestor to their respective positions
-uses morphological or genetic homologies - determines common ancestors based on common structures or macromolecules - 82phylogenetic treespictures that represent the divergence of organisms from common ancestors
nodes: common ancestors to a series of taxa
sister taxa: closely related taxa that possess the same ancestry up to the last divergence
polytomy: means "more than one tip" and refers to the nodes that brand off - 83Ecologystudy of the interactions between organisms and their respective environment.
- studies biotic and abiotic factors
ex: predators, competitors and prey etc.
or Rainfall, soil type, temperature etc - 84population ecologythe study of changes in the number of organisms within a population over time and space
requires info regarding the population size and characteristics *sex composition, age etc. - 85population densitya form of quantitative characterization of a population over space
- the number of individuals per unit space at a given time - 86population dispersiona form of qualitative characterization of a population over space
- distribution of population within an allotted space (active state where pop is expanding outwards form the space they usually inhabit)
3 forms:
1. clumped (wolf packs aggregate together to form clumps of individuals)
2. uniform (penguin nesting grounds are spread out almost uniformly, with somewhat equal distances between individuals)
3. random ( dandy lions grow wherever their seeds happen to land) - 87population growth is affected by 4 processes:1. natality or birth rate
2. mortality or death rate
3. immigration ro coming on over
3. emigration or moving on out
( assumed that the # of immigrants = the number of emigrants), so the net difference in pop size due to these actions= 0 - 88growth rate (r)the rate at which a population increases per capita (or per individual) for a certain length of time
growth rate= birth rate - death rate
*+ r = increasing pop, -r= decreasing pop size (intrinsic rate of increase is the max + growth rate a pop can undergo with ideal conditions) - 89exponential model (J SHAPE)-results from the availability of boundless resources and no spatial constraints (rare)
- 90population change formuladN/dt=rN
dN/dt is population change
r= is growth rate
N is the original population size
-population change can be denoted as dN/dt or change in N/change in t
n(t+1)=Nt + rNt
*add the change in pop to the original population size (Nt) - 91graphical representation (S shape)Y axis is N (pop size) and X axis is number of generations
- pop size grows until it approaches k, where sit goes to an asymptote
Y axis is r ( growth rate) and X axis is N (pop size) - negative linear graph, growth rate starts at max when N is low and decreases as N increases
- eventually intercepts with the X- axis at this point N=K (carrying capacity)
- true population growth is reflective of the relationship btwn pop as well as the environment ex: the hare and the lynx, both populations go through an eleven yr cycle of increase and decline, lynx is slightly staggered behind hair
(caused by 2 factors; predation of lynx on hare, availability of food for the hares - 92life history traitsdarwinian attributes that have arisen in response in response to environmental factors, both biotic and abiotic (behavioural and physiological)
- reproductive strategy is a good ex of life history trait - 93Semelparous reproduction- a reproductive strategy that uses all of the organisms energy in one big reproductive effort- insects fish, certain plants
- 94Iteroparous reproduction- a reproductive strategy that spaces out reproductive efforts so as to produce multiple offspring over many years. - more effort is generally put into raising the young, used by trees mammals and birds
- 95survival patterns: life tableused in the study of population dynamics (demography) - statistical study of populations
- summarization of vital stats including: # of individuals alive within age brackets, number of deaths within age brackets , ave age of reproductive maturity, age related survival patterns
- data from cohort or group of pop (used to predict future trends in pop, usually only considers female as they are rate limiting in terms of pop growth - 96survivorship curvesgraphical representation, showing the portions of an organism's life cycle in which it is most vulnerable
shown in 2 ways: Y axis is number of survivors, while X axis is age
Y axis is death rate per cavity while X axis is age - 97three types of survivorship curvetype 1: deaths are prevalent in older ages, (not as much in youth)
-ITEROPAROUS reproductive strategy
type 2: rate of death is constant throughout all age brackets
type 3: deaths are most prevalent at younger ages, and become less so as the organisms age
SEMELPAROUS: reproductive strategy - 98interactions between speciesa community is a group of afferent species within a set space that interact and impart change onto each other
- diff pops, - 99community ecologystudy of how the different species within a community interact to create a functional existence
- 100tolerance rangea species will spread itself out within a given space according to its specific tolerance range, dictated by lifecycle characteristics, interactions with other species and personal abilities to survive in certain abiotic conditions
- 101sharp divisions (distinguishing a community)- communities can be distinguished by sharp divisions
*due to major changes in the biotic or abiotic environment - 102ecotonethe interface between communities
- 103tolerance rangesdefine the species compliment of a community
- 104When a community is not "sharp":(distinguishing a community)the divide between communities is not as sharp
- this is caused by gradient changes in the environment
- results int eh bleeding together of different communities - 105ecological nicherole of a particular species within a community
- incorporates all biotic and abiotic considerations ex: habitat - 106fundamental nichethe potential ecological niche that an organism could inhabit, if no restricting species were present
- based solely on ABIOTIC factors of the space provided - 107realized nichethe true ecological niche that an organism settles for within a community of interacting species
- takes into account biotic factors such as competition and predation - 108types of ecological interactions:Competition(harms both)
Mutualism(benefits both)
Predation/Parasitism(does harm on one to benefit other)
Comensalism (benefits one while other is unaffected)
Ammensalism (harms one while other is unaffected) - 109intraspecific competitionoccurs within a population
- 110interspecific competitionoccurs between populations
- 111competitor exclusion principle2 species cannot share the same niche for an indefinite amount of time
eventually one will force the other to adopt a new niche or DIE - 112predationprey defences are stimulated but he ongoing threat of predators: mechanical defences- physiological hardware for defence: safety in numbers defence- creation of group proaction: coloration defence- cryptic or warning: mimicry defence 2 types :1. mullerian mimcry: when a form of harmful prey mimics the appearance of another harmful prey ex: wasp and bumble bee both have characteristic colouring
2. Batesian mimcry: when benign prey mimics the appearance of harmful prey ex: hornet moth is harmless, but is shaded similarly to a wasp - 113symbiosis- coevolution of species as a result of a close association ex: treehoppers don't consume is sometimes consumed by ants, which in turn protects treehoppers from spiders (a form of mutualism as both groups are benefiting)
- 114keystone speciesspecies whose presence greatly determines the species composition of a community ex: star fish predators
- their absence results in over population of several types of highly competitive species
-absence of keystone leads to decline in the variety of species present - 115biographyenvironmental and historical factors explain plant and animal distributions
- 116ecosystemsconsists of communities of organisms that live in an area and their physical and chemical (abiotic environments)
- 117ecosystem ecologyE flows in ecosystem
- C, N and key elements cycle through organisms, sediments, oceans, atmosphere, how humans effect environment - 118components of an ecosystemprimary producers (autotrophs): organisms that synthesize own food from inorganic materials
consumers (secondary producers): herbivores or carnivores
decomposers/ detrivores: feed on waste products or remains of other organisms - 119productivity: GPPGross Primary Productivity: rate at which C is fixed during photosynthesis
- 120productivity: NPPnet primary productivity: energy available to primary consumers (NPP= GPP -R)
R = energy released from plant cellular respiration
NPP = lowest in desert and arctic regions
Total productivity takes into account commonness of area
Total NPP =NPP per unit area X area covered by ecosystem type
- limited by water and temp
-aquatic life limited by nutrients
the + micro nutrients such S, I to oceans could increase production and help atmospheric CO2 - 121net secondary productionafter metabolism and waste is accounted for only 10% of energy moves to the next level
- 122europhicationcaused by excess of macronutrients (ex: N, P) which lead to overgrowth of algae and the subsequent depletion of H2O, and O2 levels
- 123benefits of pyramids of biomass and Eshows how ecosystems are structured
-direct effect of 10% rule
-organisms higher up are prone to extinction - 124bio-magnificationconsequence of food chains is that pollutants concentrate as they move to higher trophic levels
- 125why is the open ocean biomass pyramid interverted?most primary producers in ocean are tiny and turnover quickly
- 126biochemical cycles in ecosystemsnutrient cycle in an ecosystem via assimilation, consumption, decomposition.
-nutrients may be exported by migration - 127factors controlling rate of nutrient cycling- decomposition rate (regulated by temp, quality of detritus)
-decomposers (saprotrophs)
ex: boreal forests have extensive litter accumulation
ex: tropical wet forests have almost no litter accumulation - 128competition~ when 2 or more organisms contend for resources, food water etc.
EX: consumptive competition is when organisms compete for the same nutrients (interconnecting roots from multiple trees)
eX2: controlled experiment done by joseph ocnnell to ascertain the reason for barnacle dispersion at the water front - 129soapburry bugsexample of rapid evolutionary change.. OR its an adjustment of the organisms during development called phenotypic plasticity.... - the people in florida brought in a potential alternate host for soapburry bugs in florida. they sucked out the nectar of the balloon fruit but the bugs were there before the fruit was...
- 130Endler's Greenhouse Experimentthis experiment measured colour change and the correlation of predation. It bowed that there was evolution in guppies up stream, compared to down the stream. The male guppies downstream increased their colour spots but at the same time it was risky bc it increased their chances for predation
- not due to plasticity bc you would see it in the first generation... so its due to predation
- females being always cryptic!!!! - 131The Zika Viruspandemic, had a linkage to microcephaly
- 132spanish flulinkage to the bird flu( people came in contact with birds)
- 133chalambor et al.looked
- 134pigeons- Darwin used pigeons and tried to breed them
- he tried to figure out their genetics by evolutionary tree's - 135saltationismsudden change in one generation to the next that is macroevolution
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- 103 Bio Fichas sobre Bio 103 Evolution, creado por laurenhalliwell- el 11/04/2016.
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