how evolution works Flashcards
what are some differences between humans and some of our closest primate relatives (chimpanzees)
chimps:
- hair everywhere
- quadrupedal
- smaller brains
- simpler communication
- more advanced infants
- smaller brain:body ratio
why do humans have less hair than primates
adaptations to make our sweating an effective way to release heat
why do humans have an arched foot
for running ability
why do humans have a hyoid bone
for vocal speech production
why do humans have an opposable thumb
to carry things and make tools
T/F adaptations can be specific to local environments
TRUE
what are some byproducts that have been created as a result of human adaptations
shelter
family structures
food production systems
group systems/societies
describe the most important features that make up SCIENCE
a process
empirically verifiable information
system of hypothesis testing
experiments
updates to general understanding (public discourse)
T/F philosophy, induction, religion, math are all other knowledge productions
TRUE
induction is experience btw
what was the emission theory of vision
TRASHBIN THEORY where people believed that eyes send out invisible beams that reflect on everything to show an image of whats in front of you
what was the theory of spontaneous generation
TRASHBIN THEORY where people believed that living things could appear from nonliving things
how did the theory of spontaneous generation come to be, and why wasn’t it proven wrong
scientists had observations that went along with this theory and other similar theories, BUT THEY LACKED SCIENCE to be able to prove or disprove this theory with systematic testing of their hypotheses
why is newton creditted with disproving the emission theory of vision and not ibn al-haytham
there was no science when al-haytham disproved it, so there was no SPREADING OF INFO TO THE PUBLIC DISCOURSE
what step is missing in the method of science:
- observation
- questioning
- predictions
- experiment
- inferences
- sharing/replicating/concensus
between questioning and predictions, there are HYPOTHESIZING that has to happen.
what are the method steps of science
OQHPEISRC
our queen hears prince eric is sharing routine cuddles
observation
questioning
hypothesize
prediction
experiment
inference
sharing/replicating/concensus
what two things must be true of a hypothesis
it must be TESTABLE and FALSIFIABLE
T/F if the experiment doesn’t disprove the hypothesis, then it proves it
FALSE it only supports it, but does not show guaranteed proof that the hypothesis is true
what is a theory in general terms
a guess/tentative suggestion
what is a theory in science terms
a group of mutually consistent hypotheses that have withstood repeated attempts at rejection
what was redi’s experiment to refute the spontaneous theory of generation
REDI MEAT
jars with meat, half open/closed so maggots can lay eggs. maggots appeared from open jar not closed jar, so he concluded that they dont just spontaneously appear from meat.
t/f redi disproved the theory of spontaneous generation
FALSE he disproved that maggots spontaneously appear from meat, but cannot prove that the theory as a whole is false
what was needham’s experiment related to spontaneous generation
HAM NEEDS MORE BROTH
he boiled broth to kill anything that was already in it, but microbes appeared in both open and closed container.
he thought this proved spontaneity again
what was pasteur’s experiment related to spontaneous generation and the result
boiled broth, but this time used curved flask to show that when outside air couldn’t get in, the microbes did not appear. when outside air did get in, the microbes did appear.
THIS DISPROVED SPONTANEOUS GENERATION WITH A BOOK!
what is a peer review
an editor may send the manuscript of completed experiments and data to an expert in the subject to be reviewed for any suggests or things that were done wrong.
T/F all publications end up in general science journals
FALSE, there are some general science ones like Nature and Science, but others that are more specific in specialty journals like Current Biology and Evolution & Human Behavior
what was the early view about how the species were ordered called
the great chain of beings that was a ladder of intellect ending with angels and gods
T/F some early views of species included that they were immutable (fixed) and permanent and earth is not very old
TRUE these were common thoughts, but were later disproved
who were some prominent scientists before darwin and their beliefs
hutton & lyell thought earth must be really old
mary anning was a fossil hunter who believed in evolution
what did jean baptiste lamark believe in
- external pressure will make an animal change during its lifetime
- these traits are immediately passed down to the offspring
- traits that help an organism survive will tend to persist
- giraffe example
what is wrong about jean baptiste lamark’s theory
your acquired traits dont get immediately passed on to children
and he thought evolution was based on an end goal
what did malthus believe
species could out populate their resources.
populations can increase so rapidly, so why don’t the resources run out
who took a 5 year voyage around the world as a naturalist (collecting samples) set up by his father
charles darwin
T/F darwin finds fossils of marine animals in the mountains
TRUE in the andes
T/F darwin found fossils of giant armadillos
TRUE
what did darwin realize about islands
that the distribution of animals on the islands didn’t match what was found on the main land
- different variations of animals
- missing animals
what was the finch experiment that darwin studied
this was where darwin came up with evolution by natural selection.
- some finches on the galapagos islands were very similar but still partially different from the ones of the mainland
- he studied their beak widths, lengths, and feet size
- concluded that since they couldn’t cross breed, they must have had traits develop independently based on their survival needs that evolved separately
what is natural selection
theory that natural pressures from environment can cause a species to change without an end goal
what is artificial selection
humans will select traits that are beneficial to us, so we influence the breeding and reproduction of these traits in organisms
who was alfred wallace
he also thought of the idea of natural selection but sent it to darwin, who then said hey i also found this so they co-published this theory together
what is the main difference between natural and artificial selection
artificial selection has a main GOAL, whereas natural selection does not have any goal
what is evolution
the change in frequency of a trait over time
what are darwins three postulates called
- struggle for existence
- variation in features and survival
- variation is heritable
what does darwin’s “struggle for existence” postulate mean
populations have the ability to grow exponentially, but NATURAL CHECKS keep the population steady
- predators
- sickness
- food access
so population size remains about stable
what does darwin’s “variation in features and survival” postulate mean
traits will vary, and the most advantageous traits will be more likely to produce offspring
what does darwin’s “variation is heritable” postulate mean
offspring will inherit traits that make them more likely to survive
disadvantageous traits will likely be weeded out bc adults wont even survive long enough to reproduce or future generations with that trait wont
what are the three types of natural selection and what do they mean
directional: population traits shift in one direction (whole population changes from old to new)
stabilizing: averaging traits and eliminating outliers
disruptive: something disrupts the population so traits split with some getting one and some getting another trait
what is a better saying than “Survival of the Fittest” and why
reproduction of the fittest because a better fit to the environment will be more likely to reproduce and continue this trait, survival is part but not for the population as a whole
T/F natural selection is a mechanism that affects the species as a whole
FALSE natural selection only operates on a singular level, from parent to offspring, not across an entire species or population
T/F evolution is linear
FALSE if you think of a tree with many branches and roads going off of one to make others with branches, it would not be directly turning one species into another
T/F natural selection is a moral prescription
FALSE natural selection is facts
it is not good/bad should/shouldn’t debate
what is naturalistic fallacy
believing that everything that is nature or happens naturally is good and should happen that way
ex of when this is wrong: poison ivy is natural, but it obviously not good
T/F survival of the fittest is wrong because survival is only useful if it leads to reproduction
TRUE the phrase should be reproduction of the fittest because it is not useful if not producing offspring
T/F some species are more evolved than others
FALSE at this moment in time, all species are the exact same amount of “evolved”, but some populations had different adaptations than others that allowed them to be more progressed/developed/capable of language and concepts
T/F humans are evolutionarily unique
FALSE they are different and unusual than other organisms, but this is not because of a change in evolution
T/F natural selection is goal-oriented
FALSE it does not have a goal and will continue on and on
T/F natural selection is random
FALSE the mutations are random, but natural selection itself is not random
T/F all scientists believe that natural selection is real
TRUE they do not fight if it is true or not, but they can sometimes fight about the details
natural selection is overwhelmingly supported because of the mass amount of evidence that has not disproved it
T/F evolution is done
FALSE it will never end
T/F reproductive success is leaving more copies of your genes in subsequent generations that others do
TRUE and reproductive success is NOT having as many kids as possible
reproductive success just means that a parent must transfer their genes to their offspring, who will in the future also become parents
T/F natural selection favors what is good for the species
FALSE it is based on an individual level of adaptations for one individual to be able to successfully reproduce
T/F “fit” means traits that will help an individual progress into the next generation and have offspring
TRUE it is not solely about being the strongest or biggest, because it may be more beneficial to be small to hide or less colorful to camouflage in order to get to reproduction
what is a complex adaptation
adaptations that are too complex to just appear, but will develop through multiple adaptations over time
ex: an eye formation from nothing couldn’t just appear in one lifetime, it needed to have a crevice then start the formation which would take many many generations to do
T/F adaptations are suboptimal
TRUE in many cases, the result of adaptations is not the PERFECT DESIGN, but it works to get the job done and was how it adapted over time, without a sought out plan to come from it
what are selection pressures
anything that influences the survival or reproduction in a proportion of a population
what is optimality and why does natural selection produce it
optimality is a result that is the best result given the least amount of energy put in. think like being lazy and not studying for a test, then the highest score you can get is a 50%, but you do get the 50% so you got the highest possible for you to get as a result of the lowest energy being put in
natural selection produces optimality because it doesn’t have a goal, so it isn’t able to put in loads of effort all at once to adapt to form a perfectly designed trait
what is an obligate adaptation and an example
a trait that is expressed in the same way regardless of the environment
ex: everyone has an achilles heel and eyes, so this won’t be affected by whether you live in a brighter or darker place
what is facultative adaptation and an example and the nickname
a trait that requires input from the environment (an if-then interaction)
ex: if there is repeated contact on the skin with a rough surface, then calluses will form to protect the skin from this pain again
nickname: phenotypic plasticity
what are three things that darwin could not answer about genetics
- where does variation come from
- how does inheritance of traits work
- how is variation maintained if natural selection eliminates it
what is blending inheritance
each parent contributes equally to the offspring
why is blending inheritance less than favorable
some advantageous traits will be diluted bc there is a chance that the offspring wont inherit it if only one parent has it
what did mendel do
he figured out how inheritance works
what plant did mendel use to figure out inheritance
green and yellow pea plants that could be wrinkly or smooth as well
what color and texture was dominant for the pea plants
yellow was dominant and smooth was dominant
T/F a yellow and green plant bred together would create a hybrid yellow-green colored pea plant
FALSE they don’t mix, it would be either yellow or green based on dominance
mendel’s f1 generation (first offsprings) were always what color
they were always the dominant yellow because the parents were YY and yy so always Yy which is yellow
what percent of mendel’s f2 generation (second offsprings) were yellow
75% were yellow, 25% were green
what were the names of mendel’s three postulates and their meanings
- particles of inheritance appear in pairs: one particle from each parent (particle is known as gene now)
- genetic information is inherited from both parents, but only one parent’s info is expressed for each trait
- during meiosis, the expressed particle is randomly chosen from the two parents
know how to do punnett squares!
yay!
what is difference between genotype and phenotype
genotype is like the alleles that are present like YY or yy or Yy
phenotype is the physical characteristics that are expressed from the given genotype (yellow, green, tall, smooth, round)
what is mendel’s law of dominance
dominant allele is always expressed if present, recessive allele is only expressed if homozygous (both recessive)
what is mendel’s law of independent assortment
inheritance of one trait doesn’t affect inheritance of another (there are some exceptions to this law)
what is a genome
the complete DNA sequence of a set of chromosomes
how many pairs of chromosomes do humans have
23
what does it mean that humans have diploid chromosomes
there are two of each chromosome that are paired up
what is a gene locus
the spot on the chromosome where the gene is found
what is an allele
a gene variation
ex: the gene for color can be an allele sequence that makes it yellow (Y) or an allele sequence that makes it green (y)
what is mitosis
cell division of two somatic parent cells into two identical diploid daughter cells
what is meiosis
cell division of two diploid parents into 2 diploid daughters into 4 haploid gamete daughters (sex cells)
homozygous
same allele from both parents (whether dominant or recessive)
heterozygous
different alleles from both parents
what is a haploid cell
they only contain one copy of each chromosome instead of a diploid that has two copies
T/F a source of variation during meiosis occurs during recombination/crossing over of DNA strands
TRUE this is how the genetical material is exchanged between partner chromosomes
T/F all genes on a chromosome will have an equally likely chance of crossing over or cross-linking
FALSE if the loci are closer or matching, they will have a higher chance of linkage across and recombining there
if the two genotypes given from parents are AA and aa, and we say that the recombination rate is HIGH, then what changes with the initial probability of genotypes for the offspring
since recombination rate is high, the genes are more likely to cross-link into genotypes of Aa and aA which would be heterozygous with the dominant trait being expressed. this means that there is an even smaller chance of getting homozygous recessive aa to have that recessive trait expressed.
who discovered DNA
wilkins and rosalind frankin did all the research to figure out the structure of DNA was a double helix, but Watson and Crick stole this data and published it so they get all the recognition unfortunately
what is DNA made of
sugar and phosphate in the backbone, and they are covalently linked to nucleotide bases ACGT
T/F chromosomes are only made of DNA
FALSE they are also made of proteins
what does the base T bond to
A
what does the base C bond to
G
in RNA, what does the base A bond to
U
in RNA, what does the base G bond to
C
T/F DNA strands are complimentary
TRUE
what does the helicase enzyme do
it helps open the DNA into a fork so that replication can occur
T/F DNA replication involves conservation replication
FALSE it is semiconservative replication where the template strand is split and new complimentary strands are made to each of those
T/F mutations all have the same bad effect on the gene
FALSE mutations can be good bad or neutral, and there are a few types of mutations that will have different effects on the cells
what are the two functions of DNA
- regulatory sequences
- to make RNA that make proteins
what is the central dogma
dna - rna - proteins
what part of the central dogma makes the phenotype
the proteins lead to the observable phenotype
how does DNA turn to RNA
transcription
how does RNA turn to protein
translation
name the 3 differences between DNA and RNA
(hint: strand, backbone, bases)
RNA is single stranded, DNA is double
RNA has an extra oxygen in its backbone than DNA does
RNA uses uracil not thymine
what is transcription simple steps
- occurs in the nucleus
- DNA is opened up at the starting codon of a gene
- complimentary base pairs get connected to form mRNA that uses U instead of T
what is codon
set of 3 bases
how does the RNA get to the ribosome for translation
the mRNA transports it out of the nucleus to the ribosome to start translation
what is translation simple steps
- mRNA moves to ribosome
- tRNAs are specific RNAs that are trying to match anticodons to form a polypeptide chain
- when the right tRNA matches with the mRNA sequence, the amino acid attaches to the chain
what is intron
non coding section of DNA sequence
what is exon
coding for proteins section of DNA sequence
what are alternative splicings
when introns are spliced out, sometimes exons can also be spliced out too which would make an alternative mRNA to be turned into a protein
what determines the structure and function of a protein
the specific amino acid sequence
what percent of the human genome codes for proteins
1.5%
what is the sequence called at the beginning of a gene that uses the activator, promoter, and repressor binding sites?
regulatory sequences
what does transcription occur (related to activator and repressor sites)
when the activator is bound and the repressor is unbound
what binds to the promoter region to begin transcription
RNA polymerase
what is classical/mendelian genetics
studies how traits are passed down through pedigree analysis
what is population genetics
examines the variation within and between populations
what is phylogenetics
determines the evolutionary relationship between species to understand the evolutionary history of life on earth
what is behavioral genetics
studies how animal behaviors are influenced by their genetics
what is the nature vs. nurture debate
do the genes or environment play a bigger role in forming who you are
what is PKU
the inability to metabolize phenylalanine
how do you calculate the frequency of a dominant allele
p = freq(AA) + (1/2 * freq(Aa))
how do you calculate the frequence of a recessive allele
q = freq(aa) + (1/2 * freq(Aa))
what is the relationship between p and q
p + q = 1
what does hardy weinberg equilibrium mean
if there are no forces acting on a population, then no evolution will occur and the traits will reach an equilibrium
what are the 3 individual equations and the overall equation that relates the p and q to frequency in hardy weinberg equation
freq(aa) = q^2
freq(AA) = p^2
freq(Aa) = 2pq
p^2 + 2pq + q^2 = 1 IF EVOLUTION IS NOT HAPPENING
what is microevolution
small changes in a species (allele frequencies change)
what is macroevolution
large changes over many generations to a species (or new species emerge)
what are the four forces of evolution
- mutation
- gene flow
- genetic drift
- natural selection
what is a mutation
a change in DNA as a variation that natural selection might act upon
T/F mutations are the only forces of evolution that can create novel (new) variation
TRUE it is the only one that can create new traits that weren’t previously there before
what is gene flow
any movement of genetic information from one population to another
what is genetic drift
changes in allele frequencies based on chance
what is the bottleneck effect
a subcategory of genetic drift where a population is drastically reduced in size so the genetic variation is a lot smaller
what is the founders effect
a subcategory of genetic drift where a few members of a population leave and create a new population where everyone is now related
what syndromes can appear as a result of the founders effect
ellis-van creveld syndrome where there is dwarfism and extra phalanges
- found in many amish communities
what does natural selection produce that the other forces of evolution do not
adaptations during the one lifetime
T/F natural selection leads to differential reproductive success
TRUE which means that those individuals are more likely to leave more offspring than individuals that don’t have natural selection adaptations to their current environment
T/F most populations are in disequilibrium
TRUE most populations are still in flux and it takes a lot of time to reach equilibrium
T/F speciation is an event
FALSE it is a process
what is a species
a defined group of organisms that are similar to each other and distinguished from other groups
what is the biological species concept
species are reproductively isolated and naturally bred populations
what is a prezygotic barrier
things that prevent reproduction from occurring between species in the first place
ex: live in different place, one is nocturnal, different mating behaviors, different shaped sex organs, incompatible sperm and egg
what is a postzygotic barrier
things that prevent reproduction from occurring after copulation
ex: hybrid inviability (zygotes can’t develop to maturity) and hybrid sterility (zygotes can’t form gametes bc they are sterile)
what is the ecological species concept
the species are not reproductively isolated, but the hybrid version is not “fit” to survive in the environment
what is the reinforcement portion of the ecological species concept
natural selection will prefer to find barriers like pre and post zygotic ones to prevent the parents from producing the unfit hybrid offsprings
what is the character displacement portion of the ecological species concept
competition over food and mates increases, so the morphological differences between the first and second species will increase
what are the three main theories for how speciation occurs (how a new species arises)
allopatric, parapatric, and sympatric
what is allopatric speciation
a geographic barrier is present that splits one species so they adapt separately and form different species
what is parapatric speciation
there is a partial separation of the species, so there is a lot of reduced gene flow with only some hybrid zones
what is sympatric speciation
there is no isolation, but genetic mutations or niches may make the species diverge into a new one with some remaining in the old one
what is a niche in ecology
a way of making a living
- food eaten
- time of day active
- acquiring food
what is adaptive radiation
when a single animal/plant diversifies to fill many niches
what is anagenesis
when a species turns into another species directly
what is cladogenesis
a species splits into the same one and another one branches off
what does the tree of life tell us
- common ancestry
- time
what is the naming sections of taxonomy from largest category to smallest
domain
kingdom
phylum
class
order
family
genus
species
mnemonic:
dom the
king
purchased
cats
on
friday
+ genus + species
which two classifications are always italicized
genus and species
what classification is always lowercase
species
what two classifications do you have to put together when referring to an organism
genus and species
can’t just put the species
T/F the more shared names means the organisms are more closely related
TRUE if you share 2 names with frogs and 6 names with turtles, you are more related to turtles
what is the class, order, family, genus, and species for humans
Mammalia, Primates, Hominidae, Homo, H. sapiens
what is the genus for chimps and bonobos
Pan
what is science uses the tree of living organisms
phylogeny
what level of classification is hominoid and what animal does it include
this is a superfamily and it includes apes
be able to tell where the last common ancestor is for a tree of life
ok!
T/F if you mirror a tree of life, you just messed it up
FALSE it doesn’t matter the specific side just that the connections stay the same
what is another name for the tree of life diagram
cladogram
what is a clade
a group of organisms that includes a single ancestor and all of its descendants (aka monophyletic group)
* make sure you can find this on a cladogram
what is humans closest relative
chimps & bonobos
what are homologies/homologous traits
similarities that are present due to descent from a common ancestor
be able to construct your own cladogram
yes sir
what are homoplasies/analogous traits
similarities produced by convergent evolution
- traits that have a common function but are not inherited from a common ancestor
where are homoplasies most likely to be seen
natural selection favors similar traits in similar environments, so this is where more homoplasies might occur
what is a primitive trait
the last common ancestor had it and passed it down to this species
what is a derived trait
traits that developed after the last common ancestor split
T/F being hairless is a primitive trait for humans
FALSE being hairless is a derived trait which can be seen because our closest relatives that came from the same common ancestor are all not hairless
if the organism’s line on the cladogram doesn’t reach to the end of where the time line is, what does this mean
they are extinct
