Shared Flashcard Set

Details

Bio 1 test 4
wollslager
100
Biology
Undergraduate 1
07/01/2012

Additional Biology Flashcards

 


 

Cards

Term
lamarck
Definition
thought species changed but was incorrect about the mechanism; thought it was due to their use or disuse and acquired characteristics could be inherited
Term
voyage of the beagle
Definition
darwin got to go on a trip around the world to observe organisms, especially in south america and galapagos; noticed that species in temperate south america more closely resembled species in tropical south america instead of temperate europe and specieson galapagos most closely resembled species on mainland
Term
natural selection
Definition
darwin used the phrase decent with modification rather than evolution
Term
four observations of darwin
Definition
varation of traits in a population, traits are inherited by offspring, species are capable of producing more offspring than environment can support, therefore, many offspring do not survive to reproduce themselves
Term
two inferences of darwin
Definition
some individuals have traits that allow them to produce more offspirng than others, the unequal ability of individuals to surive and reproduce leads to the accumulation of favorable traits in populations over generations
Term
individuals do not evolve...
Definition
only populations evolve
Term
direct observations
Definition
guppy experiment, evolution of drug resistant pathogens
Term
fossil record
Definition
shows there used to be organisms that dont exist anymore and todays organisms didn't always ecist; shows transitional forms
Term
homology
Definition
similtarity in anatomy of different organisms due to common ancestry such as the human arms and bat wings and tails on human embryos
Term
vestigial structures
Definition
remnants of features that served important functions in organism's ancestors but were late selected against once they were no longer neeed, like the hind limbs of wails and the tailbone of humans
Term
convergent evolution
Definition
unrelated organisms that have adapted to similar environments in similar ways, have analogous structures rahter than homologous structures like the wings of a butterfly and the wings of a bird
Term
biogeography
Definition
study of where organisms live; evolution along with geology explain things like why there are fossils of the same speices on south ameria and africa and why island species are most closely related to species on the nearest mailand
Term
microevolution
Definition
change in allele frequencies in a population over generations
Term
average heterozygosity
Definition
a measure of the genetic diversity of an individual; the % of an individual's loci that are heterozygous
Term
mutation
Definition
the origional source of all alleles
Term
sexual reporduction
Definition
increases variation in the population by recombining genes in new ways
Term
the hardy winburg equation
Definition
p2+2pq+q2=1
Term
conditions of hardy winburg equlibrium
Definition
no mutations, random mating, no natural selecction, extremely large population size, no gene flow
Term
natural selection
Definition
the only force that chances allele frequency that causes adaptive evolution
Term
relative fitness
Definition
how many offspring one individual produces compared to others in the population
Term
direction
Definition
favors one extreme of a phenotypic ange, for expample, faovring the largest anmial the larger the better
Term
disruptive natural selection
Definition
favors either extreme of the phenotypic range, while the ones in the middle are less fit, for example, birds with large beaks can crack large seeds, birds with small beaks can crack small seeeds but birds with medium seeds can't crack either
Term
stabalizing natural selection
Definition
favors individuals win the middle of the range, while ones on the extremes are at a disadvantage; tends to keep population the same over time, for example very large or very small baby humans don't survive as well as ones around 7 or 8 lbs
Term
genetic drift
Definition
important in small populations, alleles can be lost from small populations just by chance, at random, even if they are advantageous alleles, can even cause harmful alleles to become fixed
Term
founder effect
Definition
hen a small population is founded by a small subset of a bigger population, the small population may not be representative of the biggere population
Term
bottleneck effect
Definition
when a large population is suddenly reduced in numbers, the survivors are much less genetically diverse and some alleles may be lost form the gene pool, important in endangered species conservation
Term
gene flow
Definition
genes from one population getting into another, can be advantageous or disadvantageous, advantageous if alleles coming in are favorablle; can help restore diverstiy due to genetic drift, disadvantageous if alleles coming in are not favorable in the new environment; can undo the effects of natural selection; an example would be plants adapted to a certain soil type gettin gpollen blown in from plants on another soil type
Term
sexual selection
Definition
a special type of natural selection where certain characteristics make it easier fo rindividuals to obtain mates, often results in sexual dimorphisms, where the two sexes look different, sexually slection acts upon traits that are not directly related to reproduction and survival and can even make survival harder
Term
intrasexual selction
Definition
competition between members of the same sex, like males fighting over femals
Term
intersexual selection
Definition
mate choice usually femalses choosing among various males; showy characterstics may advertise the genetic quality of different males to the females
Term
why dont things genetic drift and natural selction make all loci become fized?
Definition
have only one allele for each locus
Term
diploidy
Definition
recessive allels can be maintained in a population because they are masked by the dominat allele
Term
heterozygote advantage
Definition
the heterozygote is fitter than either homozygote so both alleles are maintained in the population (an example is sickle cell disease in africa wehre the heterozygotes are resistant to malaria)
Term
frequency dependent selection
Definition
where a phenotype declines in fitness the more common it becomes (examples ar ethe right mouthed or left mouthed scale eating fish) this causes two versions to oscillate
Term
selection can only act on existing variation
Definition
mutations dont happen on demand
Term
evolution is limited by historical constraints
Definition
organisms are tinkered with over time instead of being built from scratch
Term
compromises
Definition
organisms have to do many different things that many conflict (finding a mate vs. hiding from a predator)
Term
biological species concept
Definition
the most commonly used species concept; organisms can mate and produce viable offspring with memebers of their own species but not with members of a different species
Term
reproductive isolation
Definition
barriers that imepede members of the two species from producing viable fertile offspring
Term
prezygotic barriers
Definition
prevents sperm from fertilizing egg (habit isolation, temporal, behavioral, mechanical, gametic)
Term
postzygotic marriers
Definition
prevents zygote from developing into fertile adult (reduced hybrid viability, fertility, hybrid breakdown_
Term
limitations of the biological species concept
Definition
doesn't work on extinct species, asexual species, and species that stay distinct despite gene flow
Term
allopatric
Definition
caused by a geographic barrier that prevents gene flow between two populations
Term
sympatric
Definition
speciation occurs in populations that live in the same area
Term
polyploidy
Definition
most ommon in plants; caused by accidents during cell division duplicating chromosomes
Term
autopolyploid
Definition
all chromosomes are derived from the same species
Term
allopolyploid
Definition
polyploid that is a hybrid of more than one species
Term
habitat differenatiation
Definition
a subset of a population adapts to exploit a new habitat or resource; one example are insects that live on a certain species of plant adaptive to live on another plant
Term
sexual selection
Definition
some females in a population may come to prefer different males than other females, causing the species do diverge; one example are the lake victoria chichilid fish wehre some species seem to only be separated by the color patterns of the males
Term
hybrid zones
Definition
if two allopatric populations come back together before reporductive barriers are completely formed, a hybrid zone can be form between them where hybrid offspring can be produced
Term
possible coutcomes of a hybrid zone
Definition
reinforcement, fusion, stability
Term
reinforcement
Definition
if hybrids are less fit than pure individuals, natural selection will favor this trait that keeps each species mating with its own species rather than producing hybrids and the species continue to diverge
Term
fusion
Definition
if a hybrid individual is just as fit or even more fit than parents the two species could fuse back into one
Term
stability
Definition
if lots of gene flow is preventing natural selection from causing reinforcement the hybrid zone may persist indefinitely
Term
punctuated equilibrium
Definition
at least some species seem to arise rapdily in geologic time and then remain unchaged for a long time
Term
speciation
Definition
can occur due to a change in only one allele if that allele causes reproductive isolation
Term
miller-urey experiment
Definition
similuated conditions on early earth and produced amino acids
Term
rna world
Definition
since RNA can catalyze itself, scientists hypothesize that RNA were the first genes and DNA came later
Term
fossil record
Definition
fossils are formed from remains of organisms buried in sediment that turns to rock
Term
radiometric dating
Definition
using the half life of radioactive elements; a half life is the time it takes for half of the radiactive material to decay to another element so that after one half life you have half of the origional amount and so on
Term
earliest evidence of life
Definition
stromatolites 3.5 bya
Term
oxygen reovlution
Definition
photynthetic cyanobacteria increased the oxygen in the atmosphere between 2.7-2.2 bya rusting the iron out of the ocean to create banded iron formation
Term
first eukaryotes
Definition
2.1 bya evovled by endozymbiosis
Term
snowball earth
Definition
750-565 mya
Term
cambrian explosion
Definition
radiation of multicellular life after the earth thawed out 535 mya
Term
colonization of land
Definition
plants 500 mya
Term
tetrapods
Definition
365 mya
Term
permian mass extinction
Definition
worst of the big five mass extinctions coincided with the formation of pangaea supercontinent 250 mya followed by adaptive radiation of dinosaurs
Term
cretaceous mass extinction
Definition
probably caused by chiczulub meteor 65 mya followed by adaptive radiation of mammals
Term
CLOCK DIAGRAM
Definition
KNOW IT
Term
heterochrony
Definition
changes in the rate and timing of developmental events
Term
paedomoprphosis
Definition
retention of juvenile characteristics as an adult
Term
homeotic genes
Definition
genes that control the placement and spacial organization of body parts; mutations can cause big changes like duplications of whole body sections
Term
evolution is not
Definition
goal oriented
Term
exaptations
Definition
a structure an take on a new function different from what it was origionally used for
Term
evolutionary trends
Definition
can be misleading if extinct side brahcnes are not shown
Term
species selection
Definition
hypothesis that natural selection can work on species instead of individuals, where speciation is their birth and extinction is their death; the species that endure the longest and give birth to the most descendant sepcies determine the direction of evolutionary trends
Term
phylogeny
Definition
the evolutionary history of species or group secies
Term
systematics
Definition
a disciple focused on classifying organisms and determining their evolutionary relationships
Term
taxonomy
Definition
naming and classifying of organisms
Term
binomial
Definition
the unique name for each species consisiting of its genus name ans specific epithet whole thing italicized
Term
linnaean classification system
Definition
D K P C O F G S
Term
taxon
Definition
the level of taxonomic hierarchy
Term
phylogenetic tree
Definition
a branching diagram showing a hypothesis for the evolutionary relationships between a group of species
Term
homology
Definition
similarities species have due to inheriting them from a common ancestor such as the bone structure of the forelims of mammals
Term
analogy
Definition
similiarities species have due to convergent evolution, not common ancestry, the species evolved similar adapatations independiently because of adapting to a similar environment in a similary way such as the shape of dolphins and sharks
Term
homogy and analogy
Definition
needs to be distingues when constructing a phylogeny. analgies mistaken for homologies can cause scientiests to make the mistake of classifying unrelated species together
Term
cladistics
Definition
an approach to systemtatics that uses common ancestry as the primary criterion to classify organisms into clades
Term
monophyletic
Definition
a group of organisms that inclues an ancestor and all of its descendants; the goal of cladistics is to make all groups monophyletic
Term
paraphyletic
Definition
contains an ancestral species iwth some but not al of its descendants for example, reptiles is paraphyletic if it doesnt contain birds because birds are descended from reptiles
Term
polyphyletic
Definition
when organsisms with different ancestors are grouped together ie. kingdom protista
Term
know how to construct a phylogentic tree using pg. 543, 546
Definition
Term
phylogenetic tree lengths
Definition
can represent time or genetic distance with those variables shown on the x axis
Term
orthologous genes
Definition
homologous genes that are found in different species due to speciation
Term
paralogous genes
Definition
result from gene duplication in one genome
Term
molecular clock
Definition
a way to estimate the time of evolutationary change based on the observation that some genes evovle at constant rates
Term
neutral theory
Definition
the idea that much evolutionary change has no effect on fitness and therefore is not influenced by natural selection
Term
three domains
Definition
bacteria archaea, eukarya
Term
endosymbiont hypothesis
Definition
Term
horizontal gene transfer
Definition
Supporting users have an ad free experience!