midterm 2

Question 1

Phenotypic traits have a discontinuous distribution because?

Answer 1

they are polygenetic

Question 2

whats the difference between polyphenic and polygenic traits?

Answer 2

polyphenic traits are the multiple discrete phenotypes that can arise from different alleles within a population. Polygenic traits are traits influenced by many genes leading to a continuous distribution of phenotypic variation over a given range

Question 3

what were two important facts of charles darwin theory n evolution by natural selection?

Answer 3

• no two individuals are exactly the same, rather, every population expresses variability
• much of the variation among individuals within a population is heritable

Question 4

can genes that pass though environmental stimuli be passed to offspring?

Answer 4

yes individuals can inherit mechansims that respond to the environment

Question 5

how does broad sense heritibility differ from narrow sense?

Answer 5

broad–> the proportion of the total phenotypic variance of a trait that is attributable to genetic variance, genetic variance is a single value
narrow–> total phenotypic variance that is attributable tot he additive effects of alleles

Question 6

what source does variation arise?

Answer 6

genetic recombination, mutation, independent assortment

Question 7

what is the selection differential?

Answer 7

the difference between the trait mean of reproducing individuals and the trait mean of the general population

Question 8

what mechanism is most sensitive to variation among individuals?

Answer 8

natural selection because variation among individuals is the foundation for relative success of individuals and that relative success affects frequencies

Question 9

aposematism ?

Answer 9

an antipredator strategy used by a potential prey item to signal danger or lack of patability.

Question 10

ecological character displacement?

Answer 10

evolution driven by competition between species for a shared resource, traits evolve in apposing directions, minimizing overlap.

Question 11

selective sweep?

Answer 11

situation in which strong selection can sweep an allele to fixation so fast that there is little opportunity for recombination.

Question 12

extended phenotypes?

Answer 12

structures constructed by organisms that can influence there performance or success.

Question 13

are homologous traits ancestral or dervived?

Answer 13

they can be both ancestral or derived, depends on the clade of interest

Question 14

are synapomorphies important when developing phylogenies?

Answer 14

yes because they are shared derived traits, that can distinguish groups of species

Question 15

what is purifying selection?

Answer 15

selection that removes deleterious alleles from a population, common form of stabilizing selection

Question 16

what is boot strapping?

Answer 16

statistical method for estimating the strength of evidence that a particular branch in a phylogeny exists

Question 17

what is coalsescence?

Answer 17

any pair of homologous alleles merge in a common ancestor

Question 18

maximum parsimony is?

Answer 18

method for minimizing the total amount of change, required to fit data on a tree

Question 19

what is a cis acting regulatory element?

Answer 19

• stretches of dna located near a focal gene that influence the expression of that gene
• non coding region of the genome that can be found either upstream, downstream or inside an intron

Question 20

what are novel traits?

Answer 20

traits that arise and have no counterparts within a lineage

Question 21

what are paralogs?

Answer 21

homologous genes that arise from duplication

Question 22

what are promiscuous proteins?

Answer 22

capable of carrying out more than one function

Question 23

what is the most important element for natural selection?

Answer 23

variation within a population

Question 24

what is R=h^2 x S

Answer 24

if heritability is high, breeders create strong selection on traits

Question 25

is phenotypic plasticity heritable?

Answer 25

yes, individuals may vary in their plastic responses to the environment, and those responses may be heritable

Question 26

what is fecundity?

Answer 26

reproductive capacity of an individual

Question 27

what is mullers ratchet?

Answer 27

the process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner

Question 28

polygyny vs polyandry?

Answer 28

polyandry–>females mate with multiple males

polygyny–>males mate with multiple females

Question 29

what is sexual dimorphism?

Answer 29

females bigger than males, males more brightly coulored

differences between females and males of same species