Test 2b Flashcards
Influence of enivronmental factors and ecological interactions on the genetics of populations
Ecological genetics
Occurrence of 2 or mroe discrete types/forms in a pouplations
genetic polymorphism
When the heterozygotes for the alleles under consideration have a higher adaptive value than the homozygote. Genotypes are cyclical.
Balancing polymorphism
Genotypes are progressively replaced by another
Transient polymorphism
5 steps of failed conservation
habitat loss, smaller population size, reduced genetic diversity, reduced ability to adapt, extinction
True or false: genetic drift can maintain polymoprhism
False
What happens when only genetic drift is operating in a population
alleles will either drift to extinction or fixation
Heterozygote is more fit than either homozygote
Heterosis
Rare alleles give individuals high fitness
Negative frequency dependent selection
Frequency dependent selection example
right-handed vs left-handed scale eating fish
Different alleles favored in different environments
Variable selection
In terms of winged polymorphic insects, what advantages did wingless individuals have?
faster development, increased fecundity, increased longevity
What kind of pathogen is wolbachia
Intra-celular bacterial symbiont
What is wolbachia closely related to?
rickettsia
Where does wolbacchia specifically occur in insect bodies?
Cells of reproductive structures
% of wolbacchia occurrence in insect species
25-70%
Most species have either very low or very high infection rates
bimodal infection frequency
How is wolbacchia transmitted?
Cytoplasmically inherited by maternal eggs to offspring
True or false: wolbacchia is able to be horizontally transmitted
true
5 effects of wolbacchia on insect hosts
cytoplasmic incompatibility, parthenogenesis induction, feminization of males, early male-killing, late male-killing
a form of asexual reproduction in which growth and development of embryos occur without fertilization.
parthenogenesis
2 types of cytoplasmic incompatibility
unidirectional, bidirectional
Uninfected female x infected male = no viable offspring
unidirectional
female infected with strain A x male infected with strain B = no viable offspring
bidirectional
Wolbacchia modifying sperm such that uninfected eggs do not recognize it but infected eggs do
Cytoplasmic incompatibility
Why is cytoplasmic incompatibility beneficial for wolbacchia
infected females produce infected daughters at faster rate than uninfected females produce uninfected daughters
True or false: wolbacchia can promote speciation
True
Biological control of wolbacchia
Introduce novel strain of wolbacchia in naive host, then flood target population with infected males
Requires a long period from uptake to replication in salivary glands
dengue fever
One way wolbacchia helps its hosts
enhance host resistance to other pathogens
3 requirements of social insects
overlapping generations, cooperative brood care, reproductive division of labor
parents and offspring alive at same time
overlapping generations
offspring helping their parents care for brothers and sisters
cooperative brood care
caste of non-reproductive members of society
reproductive division of labor
Which type of insect has kings and queens
termites
True or false: castes always have strong morphological differences
False
More than one mated pair living together, but no cooperative brood care and no overlap of generation
aggregation
extended brood care; interaction ends prior to reproductive stage of offspring, no non-reprouctive caste
subsocial
How many species of eusocial insects
20,000
Rank in order of eusocial emergence: ants, wasps, termites, bees
bees, wasps, ants, termites
2 traits important to evolution of sociality
living in discrete nest, close genetic relatedness
4 reasons why living in discrete nests are important
defense from others, defense from elements, room for brood care, remodel potential
Mode of natural selection that acts on inclusive fitness
kin selection
In haplodiploid system, how are eggs produced
meiosis
In haplodiploid system, how are sperm produced
mitosis
How many n’s does a daughter have
2
How many n’s does a son have
1
Relatedness of you to a full sister
3/4
Relatedness of you to a full brother
1/4
Relatedness of you to a half sister
1/4
Relatedness of you to a full nephew
3/8
Relatedness of you to a full niece
3/8
Relatedness of you to a son
1/2
Relatedness of you to a daughter
1/2
Hamilton’s rule
rb * b > rc * c
In hamilton’s rule, what does b stand for
fitness gain to beneficiary of cooperative of behavior
In hamilton’s rule, what does rb stand for
relatedness to beneficiary
In hamilton’s rule, what does c stand for
fitness cost of cooperative behavior
In hamilton’s rule, what does rc stand for
relatedness to the individual that experiences the cost
What happens when b = c in eusocial system
Full sisters are more beneficial than your own offspring
2 conditions to allow Hamilton’s rule
queen singly mated, sisters help other sisters but not brothers
When is cooperative behavior more likely
b>c
What does multiple mating by queens or multiple queens do to a colony
sister relatedness decreases
The common good among relative
Life insurance, fortress defense
Selfish interests of individuals
larvae becoming queens
How do workers become queen
challenge old queen is she is weak
how do workers stop upstart queens
decapitation
When there is one singly mated queen, how much more do workers prefer investment in females over males
3x
What does a queen prefer in terms of sex ratios
1:1
How is the production of males controlled by workers
Worker-laid eggs often killed or eaten
3 ecological advantages of sociality
more effective defense, rapid monopolization of resources, rapid transfer of beneficial symbionts
What percent of total terrestrial animal biomass do termites and ants make up
33%
3 types of social communication
volatile pheromones, contact stimulation, sound
4 functions of social communication
kin recognition, control of workers, communication of resource location, communication of threat
How do bees communicate where food is
Waggle dance
what does the waggle dance communicated
distance and direction
