Evolution Test chp 19-23 Flashcards
Directional selection graph
pushes to one extreme OR the other
Stabilizing selection graph
pushes the graphs away from the extremes to favor the middle
Disruptive selection graph
favors both extremes
vestigial structures
remnants of features that served a function in the organism’s ancestors
shared derived traits
the ancestor that is common for all specific organisms a question asks for
Common shared ancestors/shared primitive trait
the ancestors at the bottom
sister taxa
where two organisms branch from one branch
convergent evolution
evolution of organisms that physically look the same based on their environment but they are not related
adaptive radiation
when organisms become more diverse based on the resources available
EX: Darwin’s finches-each one’s beak size evolved to the food available on the island
coevolution
when two organisms that are not related evolve together
EX: monarch butterfly and milkweed plant
allopatric speciation
speciation due to geographic barriers/isolation
So much that if the species were brought together they could not reproduce
homologous structures
similar structures in multiple species due to common ancestry
EX: bone structures
vestigial structures
features that serve a purpose at one time and are not longer used but still present
sympatric speciation
speciation that occurs in the same geographic location
EX: cichlid fish: males choose females based on coloration
analogous structures
built different but serve the same purpose
EX: bat wing and a butterfly wing
know different evidence types that prove evolution has taken place
Evolutionary change in organisms Drug resistant bacteria Homology Embryonic similarities Fossil Record
bottleneck effect
sudden change reduces a population size/random event that wipes out most of the population
founder effect
a group of organisms are separated from the rest of the population so they start their own population
natural selection
process where organisms that are most able to survive in that environment can reproduce so their traits are passed on
heterozygote advantage
having a recessive trait with a dominant trait allows that organism to have an advantage in the population
EX: sickle cell anemia recessive allele is an advantage in high malaria zones
sexual selection
male or female choosing a mate based on their characteristics or behaviors
sexual dimorphism
male and female look different
EX: cardinals, peacocks
darwin’s finches and how they show natural selection
mutations that changed the break size of the birds that allowed them to survive on the type of seed that was present on that island
beaks and behaviors based on their food source
shows adaptations due to characteristics of organisms that enhance their survival and reproduction in specific environments
intrasexual selection
males competing with other males
EX: Male Bighorn Sheep
intersexual selection
one sex chooses the other sex EX: bower bird, peacock
know the types of pre zygotic reproduction isolation and examples
prezygotic : habitat isolation (different habitats so organisms don’t come in contact with each other), mechanical isolation (can’t fit or come together), temporal isolation (different seasons for mating or different times of the day), gametic isolation (sex cells do not match due to immune system), behavioral isolation (courtship rituals are different)
review the case of the apple maggot fly
the fly’s original habitat was the native hawthorn tree, but about 200 years ago, some populations colonized apple trees that had been introduced by European settlers. As apples mature quicker than hawthorn fruit, natural selection favored apple-feeding flies with rapid development. These apple feeding populations now show temporal isolation from the hawthorn-feeding apple maggot fly, providing a prezygotic restriction to gene flow between two populations.
review the stickleback case
Marine populations of the threespine stickleback fish have a set of protective spines on their lower surface; however, these spines have been lost or reduced in some lake populations of this fish which appears to have resulted from a change in the regulation of Pitx1 gene expression, not from a change in the gene’s sequence.
gradual evolution
species diverge from one another or slow and steadily
darwin and his view of evolution
Many offspring reproduce-over produce
Competition for resources
Variation of offspring
Natural Selection is going to occur
node
intersection points
internode
between two nodes
know the types of post zygotic reproduction isolation and examples
postzygotic: reduced hybrid viability (hybrids are weak or sickly so they cannot reproduce and never make it to sexual maturity), reduced hybrid fertility (offsprin are sterile), hybrid breakdown (first generation hybrid survive second generation does not)