test 1 Flashcards
2 core tenets of evolution
living things change over time, adaptations arise through natural selection
what does evolution challenge?
the view of special creation
what are the 5 verified conclusions about evolution right now
- organisms have changed thru time
- changes are gradual
- lineages are split by speciation
- all species have a common ancestor
- adaptations result from natural selection
what causes biodiversity and adaptation
evolution!
what is biodiveristy
number and kinds of living organisms in a given area
what are the 2 meaning of adaptation
- a trait that increases an organism’s fitness
- evolutionary process that leads to such traits
2 main areas of evolutionary study
- evolutionary history
- evolutionary mechanisms
microevolution is…
studying evolutionary patterns and processes within species
macroevolution is…
studying evolutionary patterns and processes among species
goal of evolutionary history
analyze evolutionary relationships and patterns in relation to common ancestry
what does an evolutionary tree do
represents genealogy info as a tree graph
goal of the study of evolutionary mechanisms
to determine processes responsible for evolution
how is the study of evolutionary mechanisms and history related to micro and macroevolution
mechs: focus mostly on micro (in pops)
history: focus on patterns in evolution b/w populations - macro
what is the observational evolution study approach
describe and quantify
what is the theoretical evolutionary study approach
develop models
what is the comparative evolutionary study approach
obtain data from many species and analyze
what is the experimental evolutionary study approach
manipulate a system to address a specific hypothesis
what is a major property of scientific theories?
testable and falsifiable hypotheses
why are there public doubts about evolution?
personal implications of evolution, violate religious texts, it’s a young concept
who did the argument from design?
paley
what is the watchmaker argument
if every part of something has a clear purpose/intent, there must’ve been a creator
who was the first to provide a hypothesis for the causal mechanism of evolution
lamarck
what did lamarck do
theory of inheritance of acquired characters (+ graph with the circles in a triangle)
who disproved the theory of acquired characters?
weismann
what was the germplasm theory
inheritance is only by germ cells not somatic cells. somatic cells cannot change germ cells
who developed natural selection
darwin and wallace
what were darwin and wallace’s major theses
all organisms have descended with modification from a common ancestor
natural selection is the process that led to evolution
where did darwin go for school
edinburgh
what was darwin’s role on the hms beagle
intellectual companion (+naturalist) for captaion robert fitzroy
who were the 2 major inspirations for darwin
lyelle and malthus(principles of geology and population)
what is uniformitarianism
forces and processes that shape earth are uniform through time
what did uniformitarianism imply for darwin
the world was dynamic rather than static
changes build up, through the same mechanisms as in the past
what did darwin publish up until his book
wrote an essay on natural selection, linnean society presentation with wallace
what are the 3 requirements for natural selection
variation b/w individuals, heredity, fitness is variable in a given environment
IE natural selection is heritable variation in fitness
do individuals evolve?
no, populations do
is variation directional?
no, it’s random
what does fitness depend on
the environment
what were darwin’s 4 sources of evidence for evolution
geology, homology, biogeography, domestication
where did darwin spend most of his time
south america
what did darwin find in brazil
extinct mammal fossils
2 examples of a transitional fossil
tiktaalik roseae, fishapod
whale evolution
what are intermediate forms
transitional fossils linking features of diff organisms
fossils in younger strata incresingly…
resemble modern species in the same region
darwin’s university
u of edinburgh
timeline for darwin’s voyage
1831-1836
when was lyell’s book published
1830
what implications did darwin conclude after reading lyell
- dynamic world
- changes are built up gradually
what month and year did darwin doubt the fixity of species
march 1837
when did darwin read malthus
sept 1838
when did darwin write his FIRST essay on natural selection?
1844
darwin timeline for writing his book
1856-1859
when did darwin and wallace present their thing collectively
1858 july
explain the moraxella bacteria example
90% developed antibiotic resistance to a drug in 15 years
when and where was the fishapod discovered
2006 in nunavut
what is homology
similarity of 2+ traits that’s due to common ancestry
what is the bird example of homology
mainland comorants vs galapagos flightless comorants (vestigial structures)
what is the fish example of homology
surface-dwelling (gray) astynx mexicanus and cave-dwelling (pink) with no eyes
name vestigial structures in humans (4)
ear muscles, appendix, tailbone, goosebumps
estimate of number of genes shared across all forms of life
500
what are the most common shared genes (their function)
translation and transcription
what is a vestigial trait
trait with reduced or no function compared to the past
homologous structures have…
evolved to serve diff funcs
where are the flora and fauna from the G islands originally from
south america
what types of species (specific trait?) are present on the G islands
ones capable of long distance dispersal/good colonists
how did cacti get onto the G islands
by bird dispersal of their fruit seeds
how were tortoises on diff G islands diff
shell shapes + neck lengths
describe the recent study of the G island birds (species, purpose, people)
daphne major, check the reason, Dr Peter & Grant, princeton
what was special about australian flora and fauna
distinct adaptations, high endemism
australia has ____ radiations of species that are _____ with those of other continents
endemic, ecologically convergent
what is meant by the endemic australian biota
species native and only found in australia - many marsupials
how does geographical distance relate to species closeness
close = inc resemblance
examples of domestication of plants
teosinte and maize, darwins gardens
examples of domestication of animals
wolves and dogs, pigeons and funny pigeons
what is molecular evolution
evolution describing genomic DNA evidence
what is genotype vs genome
genetic constitution for a particular gene (e.g. Aa) vs the entirety of an organisms DNA
which 2/3 of the requirements of natural selection are relevant to genetics
variation and heredity (not fitness)
main 3 sources of genetic variation are…
mutation, independent assortment, recombination
name the 4 types of mutation
point, indel, changes in repeat number, chromosomal
what are possible effects of mutations (3)
silent, missense, nonsense
rate of mutation in humans (per base pair, per billion nucleotides)
16
rate of mutation per zygote
96
number of fitness-affecting mutations per genome per gen for: plant, mouse, roundworm, fruit fly, human
0.1-0.6, 0.91, 0.96, 1.2, 1.6-3
example of a single mutation with profound effects for fruit flies
antp hox gene
example of a single mutation with profound effects for humans
G6PD
polymorphism is to DNA as ___ is to proteins and ___ is to phenotypes
allozymes, polyphenisms
ignore this
..
how many gamete combos are there in humans due to independent assortment
2^23
describe recombination
synapsis of bivalents (arms), crossing over at chiasmata
the 2 theories of heredity b4 mendel
preformatism (human in sperm/egg preformed)
theory of blenfded inheritance
main conclusions that mendel made
inheritance determined by discrete particles
offspring inherit 1 gamete from e/ parent at random
how many alleles do gametes have per gene
1
2 types of traits
continuous, discrete
primary pioneers for evolutionary synthesis
fisher, haldane, wright
co vs partial dominance
co = both expressed at the same time
partial = mixed
what are some things that affect quantitative traits
genome, environment,
how does natural selection act on the genetic aspect of discrete vs continuous variation
discrete- change in frequency of alleles
continuous- change in average trait value
what is particulate inheritance
the idea that genetic material is passed down as discrete “packets” (genes)
another name for evolutionary synthesis
population genetics
what did wright do
demonstrated the evolutionary significance of genetic variation
during what molecular process do mutations happen
replication
what is genetic drift
change in frequency of alleles due to random chance
genetic drift has a larger effect on ____ populations
small
does genetic drift inc or dec variation
dec
3 types of natural selection (related to schools of thought)
purifying/neg, directional/pos, balancing
does natural selection inc or dec variation
dec (except balancing)
what is fixation
when a polymorphic locus becomes monomorphic
what is a locus
a position on a chromosome where a specific gene is located
how can fixations occur
natural selection (directional) or genetic drift
does balancing selection inc or dec diversity
inc or retain genetic variation
does gene flow inc or dec diversity
inc w/i pop, dec b/w pop
2 measures of genetic variation
heterozygosity (H), polymorphism (P)
are all polymorphic loci also heterozygous ones
no
name 3 theories of maintaining variation
mutation-selection, selection-maintaining
what is mutation-selection
predominantly negative mutations that get selected out
what is selection maintaining variation
heterozygote advantage, diversity is favoured
who pioneered the classical school for prediction of amount of genetic variation
morgan and muller
pioneers of the balance school for prediction of amount of genetic variation
ford and dobzhansky
compare classical and balance schools in terms of polymorphisms
classical - low, balance - high
what are the 2 types of genetic markers
morphological (physical traits) and cytological (genetic features)
what did early studies of genetic variation/evidence focus on (experimental)
quantitative traits with artificial breeding
2 examples of early studies of quantitative genetic variation/evidence
bristle number in drosophilia melanogaster, selection response in maize
the electophoresis guy
richard lewontin
how did electrophoresis forward research in genetic variation
able to see directly the proportion of P and H in allozymes
what did first allozyme studies indicate
high genetic variation - found evidence for all 3 schools
neutral selection guy
motoo kimura
what is the neutral theory
neg selection eliminates detrimental mutations
pos selection fixes beneficial mutations
many mutations are neutral
who’s alivia dey
compared DNA sequence diversity (big organisms = less diversity, small organisms = more diversity)
corn vs teosinte genetic diversity
corn has less bc of bottleneck
what was the arabidopsis lyrata example about
glaciated regions had lower DNA diversity
genetic drift followed recolonization
types of reproductive systems
sexual, asexual
types of sexual systems
dioecious, hermaphrodite
types of hermaphrodites
cross fertilization, self fertilization
what is transmission bias
due to meiosis, a sexually reproducing female will only pass on 50% of her genes to the next gen (as opp. to 100% for asex)
benefits of asex
female passes on more genes, maintain favourable combos of alleles, less energy for mating + finding mates, no males
benefits of sex
diff combos of alleles more common, eliminate harmful mutations faster, helpful in lottery models
what is the tangled bank hypothesis
sex inc diversity which is beneficial in competitive and variable environments
name the 2 lottery models
tangled bank, red queen
what is the red queen hypothesis
sex inc diversity which is beneficial in constantly changing environments
study related to tangled bank hypothesis
rotifer - sex inc for hetero env., sex dec for homo env.
asex species are usually where on phylogenies
at the tip - high extinction rate
types of asex
parthenogenesis, clonal propagation
which type of asex is more common in animals
parthenogenesis
what is parthenogenesis
embryo grows w/o fertilization
the species thought to be asex but probably isnt
bdelloid rotifers
2 types of mating patterns (not asex)
inbreeding and outbreeding
what is outcrossing
mating with someone else
how are gametes derived
meiotic reductive division
what is selfing
mating with yourself (not asex)
what’s a method flowers use to minimize inbreeding
timing offset for diff flower maturation
what’s are some methods animals use to minimize inbreeding
dispersal by 1 sex, delayed maturation, extra pair copulation, kin recognition
effects on the pop from inbreeding
inc homozygosity, dec H
not an effect of inbreeding
change in P, change in allele frequency
what is inbreeding depression
reduc of fitness of inbred offspring compared to outbred offspring
what are some effects of inbreeding depression
lower viability and fertility, change in allele frequencies
how much of H is lost per gen of inbreeding
50%
what is transmission advantage (selfing)
selfing variants can send out more genetic info (bc they have ovule + pollen)
example of inbreeding vs outcrossing
capsella rubella and capsella grandiflora
types of selection for quantitative traits (the graphs)
stabilizing, directional, disruptive
