Cumulative Info (w/ Unit 4) Flashcards
what is special creation?
species don’t change and are separately created
lineages don’t split
earth is young
what is descent with modification?
species change overtime
lineages split and diverge
new life comes from older forms
earth is old
what is microevolution?
changes in species
what are vestigial traits?
important in ancestors but now serves no purpose
what is the biological species concept?
if individuals interbreed and don’t produce offspring, they are SEPARATE species
when did Darwin publish “on the origin of species”?
1859
what are the four stages of evolution?
- variation among individuals
- division into distinct groups
- distinct population with little inbreeding
- irreversible reproductive isolation
what is macroevolution?
major changes that create new form from an older form
what are transitional forms?
in between organism of a species being evolved
EX: dinosaur —archaeopteryx–> modern bird
what developed first, feathers or flight?
feathers
what is homology?
the study of likeness
-human arm, mole paw, horse leg, dolphin fin, bat wing
what are nested sets?
they are used to determine what species share and use common traits b/w them
what is natural selection?
traits that promote survival and reproduction are passed to the next generation
-not always those most fit survive
-NOT goal-oriented
does natural selection work on phenotypes or genotypes? is natural selection perfect?
phenotypes
-they produce imperfect adaptations that are reflexed in a population
what is the process of natural selection?
- variation exists
- variation is heritable
- not all reproduce
- some reproduce more
what are the natural selection tenets? (modern synthesis - combining molecular science and natural selection)
- individuals exhibit variation due to mutations
- the variation is passed down to offspring
- some are more successful at surviving and reproducing
- the most successful have variation that are best adapted to their environment
what is adaptation?
traits that increase fitness relative to those that lack
what are exaptations?
adaptive traits that initially had a different function but now are used in a new way
-panda’s wrist bone shifted into acting as ‘thumb’
what is artificial selection?
-works similar to natural selection except it produces varieties less likely favored in nature
-EX: GMO’s of tomatoes
what is a phylogenetic tree? (1837)
hypothesis of the history of divergence and evolutionary change
-single species and its several descendants
-based on DNA
REFER TO DRAWING IN NOTEBOOK FOR TREE TERMS
what is a polytomy?
simultaneous divergence of taxa
-3-way split due to uncertainty and insufficient data
what are synapomorphies?
derived characteristics shared by 2+ species
what is an apomorphy?
a new derived character that appears in a tree, “separate from”
-NOT GOOD
what is a plesiomorphy?
pre-exisiting ancestral character, “near from”
-a trait in an ancestor that disappeared, but came back again later in the tree
-NOT GOOD
what are three types of groups in phylogenetics?
-monophyletic
-paraphyly
-polyphyly
what is a monphyletic clade?
ancestor and all it’s descendants
what is a paraphyly?
ancestor and some (not all) its descendants
what is a polyphyly?
some of the descendants, NOT the ancestor
what is convergent evolution?
independent appearance of a trait in different lineages
-NOT GOOD
what is a reversal?
loss of a trait in a lineage that later returns
-NOT GOOD
what is homoplasy? what creates it?
shared trait b/w species that did not come from a common ancestor
-created by convergent evolution and reversals
-comparing apples to oranges
-NOT GOOD
what does each nucleotide represent when talking about phylogenetics?
a character/trait
-must be aligned at the right character when comparing two DNA sequences
what is parsimony analysis?
simplest tree is right (KISS)
what does outgroup analysis and parsimony analysis help solve?
convergent evolution
what does outgroup analysis and parsimony analysis help solve?
convergent evolution
what does outgroup analysis and parsimony analysis help solve?
convergent evolution
what is likelihood analysis?
calculates genetic differences and produces a %
what is bootstrapping?
makes artificial data sets and gives a level of uncertainty
what is bayesian inference?
determines probability of data and tree
what is phylogeography?
comparing DNA of species in different locations
-links them to a common ancestor
-use a molecule clock to determine the time in history of speciation
what is a transversion?
purine to pyrimidine
A->C
what is a transition?
purine to purine
A->G
pyrimidine to pyrimidine
T->C
what are three types of variation?
genetic variation
environmental variation
genotype-by-environment interaction
what is genetic variation?
differences due to genes
what is environmental variation?
differences due to external factors (location, weather)
what is genotype-by-environment interaction?
differences in DNA that makes them more sensitive to environmental factors
-EX: sun burn due to pale skin
organisms alter their ___ in response to a ____ in the environment
expression changes (are/are not) heritable
proteins, change
expression changes are NOT heritable
what are epigenetic markers?
altering phenotype by changing gene expression
-chemical modifications
are epigenetic markers heritable?
YES, b/c it is changing the DNA sequence
what is reaction norm?
the pattern of phenotypes that may develop upon exposure to different environments
-talking about the phenotypes
what is phenotypic plasticity?
organism that develops different phenotypes in different environments
-talking about the organism that is displaying reaction norm
what is a synonymous (silent) mutation?
change nucleotide, AA stays the same
what is a non-synonymous (noisy) mutation?
change nucleotide, change AA
what is a nonsense mutation?
change nucleotide, AA is a STOP codon
what are indels?
insertions and deletions
-adding/deleting a nucleotide causes the reading frame to shift
what is a frameshift mutation?
the change of every codon downstream of an indel
what are paralogous genes?
genes that are duplicated w/in a genome and then diverge into a new function
-EX: mutation of the RNase1 into RNase1B
what are orthologous genes?
genes derived from a common ancestor and separated by a speciation event
-EX: RNase1 in monkey’s and RNase1 in humans
what are inversions?
multistep process of radiation causing a break in a chromosome
-creates new positions of genes (detach, flip, reanneal)
what is a cline?
regular change over a geographic location
-measurable gradient in a single trait that is different in different locations
-climate, latitude
what is a polyploid?
2+ chromosome sets for better adaptation to their environment
a population not under natural selection will ____ in average fitness overtime
-under natural selection, bad mutations ____
decrease
“weed” out
what is population genetics?
the change across generations in the frequency of alleles
-can save endangered species through migration, genetic drift, and nonrandom mating
is H-W used in nature?
no
-it is an idealized baseline
under H-W, what does not change from generation to generation?
allele frequencies
under H-W, what letters represent allele frequencies? which one represents the dominant allele? recessive allele?
p: dominant allele
q: recessive allele
under H-W, what letter represent genotype frequencies? which one represents the the dominant genotype (WW)? heterozygous genotype (Ww)? recessive genotype (ww)?
p^2: homozygous dominant genotype
2pq: heterozygous genotype
q^2: homozygous recessive genotype
what is the overall H-W equation?
p^2 + 2pq + q^2 = 1
what are the five H-W principles?
- no selection
- no mutation
- no migration
- no chance events (genetic drift)
- individuals chose mate at random
what are the four processes that cause evolution? which ones are the most powerful when acting together?
- mutation
- migration
- selection
- drift
(mutation and selection are most powerful together)
what is selection?
particular phenotypes survive and reproduce
(+): increases favorable allele (more noisy mutations)
(-): decreases harmful allele (more silent mutations)
does selection lead to homozygosity or heterozygosity?
heterozygosity
what is frequency-dependent selection?
favor the more rare trait
-bee and flowers (always wanting the more rare color)
what is mutation?
error in transcription of alleles
-very little impact on population
what happens to mutation rate when there is high selection?
low mutations
what happens to mutation rate when there is low selection?
high mutation
why are mutations and selections important together?
mutations allow selection to occur
-EX: original stock of flies died b/x they lacked salt mutation
what is migration?
movement of alleles b/w populations (gene flow)
does migration lead to homozygosity or heterozygosity?
homozygosity
what is genetic drift?
change in allele frequencies due to random change, not natural selection
-big effects on small populations (bigger than selection!)
what is the founder effect?
high rates of rare heritable traits
-EX: achromatopsia in pingelapease people
what happens when mutation + selection + genetic drift work all together?
-harmful alleles appear and are lost due to selection
-neutral mutations appear and are fixed/lost by chance
-advantageous alleles appear and are swept to fixation by selection
what is the neutral theory of evolution?
neutral mutations occur more than most DNA changes due to natural selection
what is hitchhiking?
as favorable mutations increase, the genes linked to it will increase too
what is nonrandom mating?
the most common type of this is inbreeding:is the mating b/w genetic relatives
does nonrandom mating lead to homozygosity or heterozygosity?
homozygosity
-which is why it’s bad because it can be homozygous for bad alleles
what are three principles of adaptation?
- differences b/w populations/species are not always adaptive (selectively neutral)
- not every trait or use of trait is an adaptation
- not every adaptation is perfect
what are experiments?
determining a single variable b/w groups
what is a null hypothesis?
NO CHANGE in variable differences
-what experiments disprove
what are the four principles in designing an experiment?
- define and test effect control groups
- all groups (& controls) must be tested the same
- RANDOMIZATOIN
- must be able to repeat the test on individuals
what is observation?
relationship b/w 2 variables and yield data for a hypothesis
-when experiment is impractical
-EX: snakes and thermoregulation at night
-EX: nematode worms moving to places where fitness is best
what is the comparative method?
comparing existing stats with historical stats to see correlations
EX: sperm, teste size, and bats
what are phylogenetically independent contrasts?
removal of divergence from common ancestor
what are the five steps in asking a good question?
- study natural history
- question obvious/conventional wisdom, often untested
- question assumed population hypotheses, be skeptical
- draw analogies from taxon to taxon or population to population
- ask why not?
what is overdominance?
heterozygotes have higher fitness
what is underdominance?
homozygotes have higher fitness
what is sexual selection?
form of natural selection where individuals w/ certain inherited traits are more likely to obtain mates
-EX: peacock big feathers in males, not in females
what is the difference b/w natural selection and sexual selection?
sex: only deals with differences due to mating success
nat: deals with all other components of fitness
what is intRAselection?
members of the sex subject to strong selection will be COMPETITIVE
-w/in sexes (male vs male)
what is intERselection?
members of the sex subject to weak selection will be CHOOSY
-b/w sexes (male vs female)
what are two reasons to be choosy when picking a mate?
-get food/resources from mate
-get better genes for offspring
is it better to have a singular mate, or multiple mates?
multiple
what is a species?
species cannot interbreed
-creates reproductive isolation
what is integrative taxonomy?
using multiple lines of evidence (genetics, morphology, geography, ecology) to determine whether or not a species is evolving independently (creating a new species)
what is speciation?
disruption of gene flow and populations become genetically isolated
-the four stages of evolution proved this
what is allopatric speciation?
new species in population separated by a geographical barrier
-due to vicariance (new barrier) or dispersal (migration)
what is sympatric speciation?
new species in a population due to food source or characteristic that occurs spontaneously
-no physical barrier
what are two ways the sympatric species are kept separate?
prezygotic isolation
postzygotic isolation
what is prezygotic isolation?
mating b/w species never takes place
-reinforcement
-incompatibility
what is postzygotic isolation?
offspring are not viable, sterile, or have reduced fitness
what are some evolutionary traits shared with humans and chimps?
absence of tail
erect posture
increase flexibility of wrists and thumbs
how many years ago did humans and chimps split off from each other?
5.4 million years ago
what is hominin radiation?
w/in 4 million years, there was multiple species in Africa of homosapiens
-we are survivors of that extinct radiation
what lead to the distinction between previous humans?
breeding with Neanderthals
are we genetically diverse compared to primates?
no
if we aren’t genetically different than primates, why are we different?
we show geographical patterns of diversity
-due to differences in people’s environments (guns, steel, domestication)
-not biological differences
what is the fertile crescent?
earliest human civilization area (10,000BC)
-domestication, agriculture
what is the path of least resistance?
spread of civilization from east -> west based on it being easier to domesticate
-there was UNEQUAL starting points relative to civilization
what is the civilization pathway?
hunters & gathers -> Ag -> food production -> population growth -> culture -> technology -> conquest for land (goes back to Ag to start again)
who was Francis Galton?
Father of Eugenics
what occurred during the American Eugenics Movement? (early 1900’s)
they believed that they should promote reproduction of good qualities and disprove reproduction of bad qualities
-created state and federal laws
-people were seen as a burden
-EX: no interracial marriage
what did the Bucks vs Bell Supreme Court Ruling pass?
forced sterilization
-used pedigrees to justify for this
-characteristics such as: alcoholic, insane, pervert, etc.
