exam 3 Flashcards
lamarckianism
traits acquired during the life time of an individual were passed on to offspring
darwins theory
natural selection or genetically based variation leads to evolutionary change
charles lylell principles of geology
earth is much older than 6000 yrs old earths geology is formed by slow moving forces
thomas robert malthus
an essay on the principle of population 1798 human population will be limited by factor such as food water some individuals die others survive
favorable variations would tend to be preserved and unfavorable ones to be destroyed
charles darwin
alfred russel wallace
closely related species occupied neighboring geographic areas barriers such as the amazon separated related species
descent with modification
traits vary among individuals individuals with certain traits reproduce and have more offspring
Staph infections
30-40% of healthy people carry staph infection begins with little cut or surgical wound with gets infected staph can be minor (fingernail infection) or ver serious and lead to death -organ failure
high risk of staph
athletes people with weakened immune systems infections of surgical wounds
Antibiotics
chemical (drugs) that kill bacteria or slow their growth by interfering with function of cell structure
history antibiotics
a fungus penicillium can kill bacteria 1928 for decades antibiotics treated bacterial infections and death rate due bacteria dropped resistance started to emerge some staph strains resist every type of treatment
how do bacteria quire resistance
mutation and gene transfer
Mutation
creates new genetic diversity by creating new alleles
what is an allele
variant of a gene
cystic fibrosis is caused by …
a mutation in the CFTR gene cystic fibrosis deletes the CTT-which interferes with gene function
what is a population
group of the same species that live together in the same geographic area
how do populations evolve
a new trait can raise when that trait is favored it is advantageous to have that trait
fitness
how well an individual does -survival and reproduction resulting in offspring
Factors related to fitness:
- survive
- reproduce
- offspring quality
evolution
is the change in allele evolution over time
what happens when a trait is favored (over others)
the alleles that code for those traits increase frequency over time
natural selection
favors some traits over others the population shows adaptation
adaptation
advantageous traits become more common in population over time
evolution by natural selection occurs in populations or individuals ?
populations individual organism do not experience a change in allele frequencies over time therefore individuals don’t evolve
sexual selection
occurs when traits used in attracting mates vary and individuals with certain traits attract the most mates
inbreeding
the mating between relatives is the most intensively studied form of nonrandom mating
consequences of inbreeding
because relatives share a common ancestor individuals that breed with relatives are likely to have the same alleles
how does inbreeding influence evolution
although inbreeding does not directly cause evolution it can speed up the rate of evolutionary change it increases the rte at which natural selection eliminates deleterious alleles from a population
genetic drift
its all about chance random fluctuations in the number of alleles in a pulsation an allele may increase or decrease by chance over time
founder effect
few individuals colonize and establish small isolated populations new population is likely to have different allele frequencies than the source population by chance
population bottle neck
a sudden reduction in the number of (different) alleles in a population
the effects of genetic drift are most pronounced in
small isolated populations
the colonization of beetles on an island that never had those beetles before is an example of
founder effect
the following is false regarding genetic bottle necks
results from a disease that targets individuals that already weak or inferior
what are the consequences of gene flow
serves to homogenize (make the same) all frequencies between populations
the movent of alleles from one population to another
occurs when individuals leave one population join another and breed
the genetic difference between two populations will (increase/decrease) after gene flow
increase
mutations introduce____
new alleles
why do mutations have such a big effect on bateria?
because they have such a short generation time (reproduce rapidly)
which process is not likely to be operation in a system where there is binary vision and not sexual reproduction
gene flow
a null hypothesis hardy weinberg
allele frequencies in a population do not change over time
frequency for the AA Genotype
pp or p^2
the frequency of the Aa genotype is
2pq
the genotype frequency of aa is
qq or q^2
p^2+2pq +q^2=
1 genotype frequencies
p+q=1
alle frequencies
alle frequencies in a population do not change over time as long as there is
- random mating - mating choice 2. no selection.-all individuals survive and reproduce 3. no genetic drift - infinitely large population size no getting lucky 4. no mutation -no new alleles 5. no gene flow - no alleles gained or lost due migration and mating THIS DOES NOT EXIST
HOW DO EVOLUTION PROCESS AFFECT POPULATIONS
TEST ALLELES IN POPULATION AGIAINST THE NULL HYPOTHESIS OF NO CHANGE 2. use a mathematical model to predict how different forces would change alleles 3. collect data and test predictions
which is stronger ? drift vs selection ?
in small populations genetic drift can be very strong in larg population selection is strong
how do our evolution processes lead to the evolution of a new species
Macroevolution
biological species concept
reproductive isolating mechanisms the biological species concept focuses on the ability to exchange genes
reproductive isolating mechanisms
barriers tp succesful reproduction prezygotic isolating mechanisms postzygotic isolating mechanisms
prezygotic isolating mechanisms
mechanism that prevents formation of a zygote individuals are prevented from mating Behavioural isolating temporal habitat genetic barrier mechanical barrier
postzygotic isolating mechanism
mechanism that prevents development into an adult individuals mate but the hybrid offspring are sterile have low fitness or don’t survive
biological species concept disadvantages
the criterion of reproductive isolation cannot be evaluated in fossils or in species that reproduce asexually hybrids do well
the phylogenetic species concept
is based on reconstructing the evolutionary history of populations
what are the disadvantages of the phylogenetic concept
phylogenies ae currently available for only a tiny (though growing) subset of populations on the tree of life critics point out that it would probably lead to recognition of many more species than either of the other species concepts
speciation
the process of forming new species
populations are rocognized as distinct species from each other if they are
reproductively isolated form a distinct phylogenetic lineage on the tree of life
speciation most likely occurs in what type of geographic location
isolation such as islands
2 parts of speciation
- initial identical populations must diversify 2.reproductive isolation must evolve to maintain these differences
why must gene flow cease for speciation to proceed
because gene flow homogenizes populations -makes them the same-
Allopatric vicariance
physical barrier
allopatric dispersal
no barrier just move
species-recognition cues
diverge to a greater extent when two distinct populations co-occur (sypatric)
REINFORCEMENT
Selection for species recognition traits that prevent hybridization is called REINFORCEMENT
REINFORCEMENT increases the morphological divergence between populations - this mode of selection is called _________ selection (removing intermediate form)
DISRUPTIVE
Adaptive Radiation
the rapid diversification of a lineage that results in many closely related species with a wide range of adaptations
he colonization of ancestral tarweed from California to the Hawaiian islands that led to the formation of a new species (silversword) is an example of
speciation via ___________
dispersal
phenotype
the expression of a trait
genotype
the sequence of DNA for the allele of a gene
requirements for natural selection?
- Individuals within a species are variable
- Variation in a trait is (at least in some part) heritable – that is, passed on to offspring
- In every generation, some individuals are more successful than others at surviving and reproducing
- Survival and reproduction are NOT random, but tied to the heritable variation among individuals. Some individuals survive and reproduce more than others
mutation in mc1r gene
melanocorton 1 receptor (skin pigmentation)
homology
similarity due to common descent
acclimate
when you go to high elevation - you produce more red blood cells
then, when you descend the mountain, you stop producing excess oxygen-carrying red blood cells
NO CHANGE IN ALLELES
evolution Adaptation
An allele that increases the ability to hold oxygen has evolved in Tibetans. This allele is absent/rare in human populations that live at low elevations
CHANGE IN ALLELES in a population
Cystic fibrosis (CF)
is caused by a mutation in the CFTR gene
what is the ‘gene pool’
all the genetic information (all the genes and all alleles) in a POPULATION
directional selection
favors a change in the mean phenotype
Disruptive Selection
favors the extreme phenotypes
Stabilizing Selection
From a conservation perspective, isolated populations are at risk. This is because small, isolated populations tend to experience inbreeding, leading to a loss of genetic diversity. Small isolated populations are also more susceptible to the effects of __________
genetic drift
One way to connect isolated populations is to modify the habitat so that individuals can move between populations and breed, thus bringing new genetic variation into the population through ______________
gene flow
Which of the following are TRUE regarding key innovations.
A. many of the synapomorphies we studied on the tree of life are examples of key innovations
B. key innovations are traits that allow descendents to live in new areas and exploit new resources
C. key innovations are NOT likely to improve fitness, and therefore, are NOT expected to evolve through selection
D. feathers for flight and lungs to breathe air are examples of key innovations
A. many of the synapomorphies we studied on the tree of life are examples of key innovations
B. key innovations are traits that allow descendents to live in new areas and exploit new resources
D. feathers for flight and lungs to breathe air are examples of key innovations
flood separated a large population into two populations. The isolation persisted for a very long time such that those two populations diversified and speciated. Then, the land masses are reconnected. Which of the possible outcomes listed below are possible if gene flow was NOT restored between the two species.
the differences between the species are exaggerated when they come back into contact
continue to diversify and not breed with each other
fuse back into one species
mate and have offspring that form a new species
the differences between the species are exaggerated when they come back into contact
continue to diversify and not breed with each other
This phylogeny shows the relationships among six supspecies of seaside sparrow. You are a conservation biologist and will breed fisheri with another subspecies to save its declining populations. Which of the following subspecies should NOT be bred with fisheri?
nigrescens
Maritima
Macgillivaraii
