Midterm 2 Flashcards
plesiomorphy
refers to the ancestral character state
apomorphy
a character state different than the ancestral state, a derived state
synapomorphy
a derived character state that is shared by two or more taxa due to common ancestry
autopomorphy
a uniquely derived character state
monophyletic
a group that contains all of the descendants of a common ancestor - clades
paraphyletic
a group that contains some but not all of the decedents of a common ancestor
reptiles are a paraphyletic group b/c birds also share a common ancestor but are not included in the group
polyphyletic
assemblage of taxa that have been erroneously grouped on the basis of homoplaious
homology
a character state that is shared b/w DNA sequences or taxa may be so b/c they share a common ancestor
homoplasy
a shared character state shared but evolved independently
convergent evolution
independent evolution from different ancestral state
parallel evolution
independent evolution from the same ancestral state
analogy
non homology, fins of sharks and whales are homoplasy due to reversal, whales reverted back to the ancestral state in water after evolving as mammals on land
principle of parasyimony
simple explanations are preferred over complicated ones
coevolution
the process where evolutionary changes in one species drive changes in the traits of another species. can involve predator and prey, parasite and host,
adaption
a trait that increases the fitness of an individual in comparison to an individual without said trait - arises from natural selection maybe effected by genetic drift and migration
trade-off
a compromise b/w one trait and another that cannot be avoided
constraint
a factor that tends to retard the rate of adaptive evolution or prevent a population from optimizing a trait
phenotypic plasticity
identical genotypes can have different phenotypes in different environments
obligate parthenogenesis
entire species consists only of females that reproduce by creating identical clones of themselves
cyclic parthenogenesis
females reproduce by cloning for most of the year, environmental cue triggers production of males, leading sexual reproduction. then parthenogenesis will continueq
gynogenesis
heterospacific sperm from a similar sexual species activates the egg by being in close proximity
sperm doesnt fuse with the ovum,
hybirdogenesis
The ovum is haploid and the heterospacific sperm from a related species is incorporated into it to form a diploid zygote. the paternally contribution is then lost premitoticly producing haploid ova that contain only the maternal genes.
hermaphrodites
organisms have both male and female gonads and are capable of self-fertilization.
still a form of sexual reproduction b/c gametes are still formed by meiosis but results in less genetic diversity than outcrossing
why does sex exist
a females reproductive mode does not:
affect the number of offspring she can have
affect the probability that her off spring will survive
what does sex boil down to?
mating b/w different individuals resulting in new combinations of genes in the off spring
recombination and crossing over in gametogenesis
linkage disequilibrium
linked genes are located close to one another on the chromosome and are inherited as a single unit. genotype at two different linked loci will not be randomly associated with one another.
recombination during meiosis breaks up linked genes and breaks down linkage disequilibrium
the genetic load
over time asexual organisms accumulate deleterious mutation, resulting in lower fitness
the total number of mutations and the resulting reduction in average population fitness. this will eventually get so high that the population goes extinct
red queen hypothesis
an evolutionary advance by a pathogen results in the evolutionary advance of the host and visa versa - coevolution
sexual dimorphism
refers the the phenotypic difference b/w males and females. in many cases cannot be explained by viability selection.
sexual selection
differential reproductive success resulting from differing abilities to find a mate
parental investment
refers to the energy, time, and resources devoted to mating, gestating, and caring for offspring. typically much greater for females
asymmetry in reproductive potential predicts
the sex under the stronger sexual selection will be competitive
the sex with the weaker sexual selection will be choosy
intrasexual selection
male-male combat can favour traits such as large body, armour, antlers and other offence/defence structures
infantacid
males will kill other males cubs to get a chance to mate with the female. this creates conflict b/w females and new males who take over the pride.
bruce effect
termination of pregnancy in the presence of unfamiliar males take over the group rather then invest in the doomed offspring they abort
way are females so choosy?
- get better genes
- pre-existing sensory bias
- resistance to parasites/better health
- to get better a better provider for resources and protection
consequences of asymmetric reproductive potential
the sex subjected to stronger sexual selection will be competitive (and possibly mate with multiple)while the weaker one will be choosy
four types of social behaviour
mutually beneficial - both gain
selfish - gain for actor loss for recipient
altruism - loss for actor gain for recipient
spit - loss for both
direct vs indirect fitness
direct - an individual’s direct contribution to the next generation by reproduction
indirect - arises by additional reproduction of close relatives that result from the actor’s actions. additional reproduction will not occur if it wasnt for the actor
kin selection
the selection and spread of alleles that increase indirect fitness
hamilton’s rule
an allele for altruistic behaviour will spread if is the (benefit for the recipient) relatedness - cost to the actor > 0
topological/morphological species concent
type specimen - an individual that represents the whole species. specimens are considered to be of the same species if they agree morphologically to the type. but species show a continuum of variance
cryptic species
cannot be distinguished based on their morphological characteristics
biological species concept
groups of inbreeding natural populations that are reproductively isolated from other such groups.
individuals with in the population resemble one another do to interbreeding and gene flow
difficult to test. cannot be applied to those who are extinct asexual or hybridize freely
phylogenetic species concept
consists of populations or groups of populations the share a common evolutionary fate through time
can be applied to living, extinct, and asexual
based on evolutionary independence - can be applied without direct observation
allopatric speciation modle
- physiological isolations of populations
- divergence of isolated populations
- reproductive isolation
- posible secondary contact
what drives divergance
once allopatric isolation has occurred mutation, genetic drift, bottle necks, viability, sexual, and fecundity selection can independently act on the populations, placing them on separate evolutionary trajectory
sympatric speciation
when isolation and divergence occur at the same time.
key features are positive assortative mating and disruptive selection
resource polymorphism
individuals within a population being to specialize on different food sources.
premating reproductive isolation
prevents zygote from forming.
ecological, behaviour (different mating songs), mechanical
postmating reproductive isolation
mating can occur but offspring die, are not well adapted, or sterile
zygotic/embryonic/arval mortality, hybrid inviability, sterility
hybridization
can occur when recently diverged species come back into contact.
hybrid zones - areas where interbreeding occurs and hybrid are at a high rate
three major outcomes of hybridization
- hybrid have lower fitness than the parental lineages, this results in reinforcement, character displacement, and short lived hybrid.
- have equal fitness, lineages will interbreed and merging back into a single - introgressive hybridization
- have higher fitness, can displace the parental species or form a new species
what is reinforcement and character development
reinforcement - assortative mating will result in evolution of an isolating mechanism that prevents hybridization
in turn will cause character development - disruptive selection that causes differences b/w parental the two parental lineages
biogeography
the science devoted to recognizing spatial patterns of biodiversity. study of the distribution of organisms (species and higher taxa) in both past and present
dispersal vs vicariance
dispersal is the movement of organism away from their point of origin
vicariance is the splitting of fauna or populations as a result of the formation of a physical barrier
what was the great american interchange
a major dispersal event that was due to the formation of the Isthmus of Panama creating a land bridge b/w north and south america
a vicariance event due to the rising of the land bridge isolating marine species in the Pacific and Caribbean resulting in allopatric speciation forming sister taxa on opposite sides
why was the interchange “one sided”?
previous to this NA was in contact with the Asia. this allowed fauna that were well adapted to dispersal to migrate into NA. when the SA and NA formed contact the fauna who were well adapted for dispersal moved into SA
law of germinate species, Jordan’s Law
the nearest related species is found in a neighbouring district separated from the first by a barrier of some sort. will always see sister taxa adjacent to one another.
not considered a law today b/c dispersal
by dating the barrier we can estimate the rate of evolution
phytogeography
the study of the geographic distribution of genetic variance.
usually conducted by DNA sequencing representatives of the species over it’s geographic range
provides insights into the process of allopathic speciation provides evidence that different taxa have been effected by the same vicarience events in different ways
latitude gradient species diversity
species diversity and number of endemic species increases from poles to the equator
this is due to historical factors (glaciers), ecological factors (climate), and evolutionary factors (rate of speciation/extinction)
Rapoport’s rule
the range occupied by a species increases as you move from the equator to the poles
profligate
wasteful or someone with low morals
screed
lengthy piece of writing or speech
Erudite
very knowledgeable through study, showing or having great knowledge gained from study and reading
Barmy
nonsensical, irrational, and completely lacking good sense or reason
odious
hateful or extremely unpleasant, inspiring hatred, contempt, and disgust
bilious
nauseating/sickening exceptionally unpleasant or objectionable
incucate
to fix something firmly on someone’s mind through frequent and forceful repetition
pusillanimous
very weak spirited showing lack of strength or determination
annus horribilis
an awful year or year of horrors
annus mirabilious
a remarkable year, wonderful b/c of great and spatular events
Vituperation
an outburst of abusive, violent, and harshly critical language
gregarious
very friendly, sociable, having preference for being with others
ebullient
cheerful, lively, highly enthusiastic
Perfervid
passionate and enthusiastic towards something
Salacious
having sexual contact, intending to arouse by means of explicit sexual contact
Pugnacious
Very quarrelsome or argumentative, inclined to pick argument and fights
Replete
full, the tank is replete with fuel
Gourmand
someone who really likes food and tends to eat quite abit
Transmogrify
the change appearance in a horrifying or grotesque way
Redolent
strongly smelly, having a well defined odor
Obsequious
one who is very eager to obey orderers
sycophant
a fawn flatterer, someone who obsequiously flatters a powerful person
Loquacious
having a tendency to talk a great deal
Pedantic
overly concerned with formal rules and details, nitpick
