BIO286 EXAM 2 VOCAB - Spring 2024
Comprehensive Questions and Answers
with 100% Accuracy |Updated 2025. 177
Questions and Correct Answers.
Life History
Pattern of how organisms allocate time and energy among the various activities throughout its life
that affect survival, maturation, and reproduction
Life History Traits
Longevity, growth rate, age at sexual maturation, age at first reproduction, number of reproductive
bouts per lifetime, number of offspring per reproductive bout
Ecdysis
periodic shedding of the cuticle in arthropods or the outer skin in reptiles (cicadas in lecture
example)
Subimago
A life stage of certain insects that is NOT sexually mature, comes before the imago stage.
Imago
Sexually mature version certain insects molt into after the subimago stage; Imagos don't have well-
developed mouthparts, so their main goal is to breed before they die.
Iteroparous
Species that reproduce multiple times during their lives (ex: humans, dogs, frogs, etc)
Semelparous
Species that reproduce only once in their life, but may produce MANY offspring during that one time
(ex: mayflies, tussock moths)
Iteroparity
A survivorship pattern related to reproductive patterns; often typical of organisms whose survival
chances increase once they reach maturity (type 1 or 2 survivorship, but iteroparous organisms may
have type 3 survivorship curves as well)
Semelparity
A survivorship pattern related to reproductive patterns; often typical of organisms with type 3
survivorship (high early life stage mortality), including many fish, insects, all annual plants, etc
Phylogeny
,a synonym for 'evolutionary tree,' a hypothesized diagram showing the history of divergence and
change from single ancestral lineage to its descendants,
Parsimony
used when constructing evolutionary trees; choice among alternatives that require fewest number
of evolutionary changes; the least complex explanation to explain data. Also explains relationships
among organisms: similarities and differences (appearance, function, DNA, proteins), tips of
branches (different species), and common ancestors (branch points)
Homologous characters
those that are similar in different organisms because they were derived from a common ancestor.
Ex: vertebrate forelimbs
Analogous characters
traits that serve a similar function but have separate evolutionary origins, a result of convergent
evolution. Ex: bird and bat wings.
Convergent evolution
similarity between species in certain traits that is caused by similar, but evolutionary independent,
responses to common environmental problems.
Homoplasy
similarity in the characters found in different species NOT inherited from a common ancestor. Ex:
cacti and euphorbs
Parallel evolution
similar phenotypes arise form similar developmental origins in different species. Ex: attachment
organs in larval stages of blind cave fish
Taxon (taxa)
any group of species that we designate or name (like vertebrates)
Clade
a taxon that consists of all the descendants of a common ancestor
Vertebrate clade
having an embryo that develops within an amnion (an adaptation to laying eggs on land) includes
reptiles, birds, and mammals
General events leading to speciation
populations become isolated physically, beahviorally, etc; populations diverging in 1+ traits (mating
behavior, etc); reproductive isolation
Why do rates of speciation vary?
habitat specialization, diet specialization, changes in ploidy
Ploidy
, an organism doubling their own chromosome number or being fertilized by another species and
then doubling chromosome number
2 commonly recognized modes of speciation
Allopatric and Sympatric
Allopatric Speciation
among populations with discontinuous distributions; dispersal, peripatric, and vicariance
Allopatric dispersal
new populations established in area and subjected to unique selective pressures
Peripatric
small isolated population drifts to become reproductively isolated
Vicariance
existing populations divided by physical barriers, ex: snapping shrimp in Panama
Sympatric Speciation
among populations with overlapping distributions; reproductive isolation must occur without
geographic isolation
Migration
Physical movement from one area to another and back again; allows organisms to track resources
and habitat quality; carries risks of predation and starvation; may be under genetic control (like
Monarch butterflies)
Dispersal
The one-way movement of an individual from the natal area; results in gene flow if dispersers breed
in new habitat; introduces mortality risk associated with movement
Natal dispersal
Moving away from where born prior to reproduction; may be independent of environmental
conditions, thus minimizing the probability of inbreeding (ex: male belding's ground squirrels leaving
after reaching a certain weight)
Pre-saturation dispersal
occurs before resources become sparse
Saturation dispersal
the dispersal to avoid the shortage of important resources such as food or nest sites
Phylopatry
the lack of dispersal; organisms mature in the habitat in which they were born
Polyandry
Comprehensive Questions and Answers
with 100% Accuracy |Updated 2025. 177
Questions and Correct Answers.
Life History
Pattern of how organisms allocate time and energy among the various activities throughout its life
that affect survival, maturation, and reproduction
Life History Traits
Longevity, growth rate, age at sexual maturation, age at first reproduction, number of reproductive
bouts per lifetime, number of offspring per reproductive bout
Ecdysis
periodic shedding of the cuticle in arthropods or the outer skin in reptiles (cicadas in lecture
example)
Subimago
A life stage of certain insects that is NOT sexually mature, comes before the imago stage.
Imago
Sexually mature version certain insects molt into after the subimago stage; Imagos don't have well-
developed mouthparts, so their main goal is to breed before they die.
Iteroparous
Species that reproduce multiple times during their lives (ex: humans, dogs, frogs, etc)
Semelparous
Species that reproduce only once in their life, but may produce MANY offspring during that one time
(ex: mayflies, tussock moths)
Iteroparity
A survivorship pattern related to reproductive patterns; often typical of organisms whose survival
chances increase once they reach maturity (type 1 or 2 survivorship, but iteroparous organisms may
have type 3 survivorship curves as well)
Semelparity
A survivorship pattern related to reproductive patterns; often typical of organisms with type 3
survivorship (high early life stage mortality), including many fish, insects, all annual plants, etc
Phylogeny
,a synonym for 'evolutionary tree,' a hypothesized diagram showing the history of divergence and
change from single ancestral lineage to its descendants,
Parsimony
used when constructing evolutionary trees; choice among alternatives that require fewest number
of evolutionary changes; the least complex explanation to explain data. Also explains relationships
among organisms: similarities and differences (appearance, function, DNA, proteins), tips of
branches (different species), and common ancestors (branch points)
Homologous characters
those that are similar in different organisms because they were derived from a common ancestor.
Ex: vertebrate forelimbs
Analogous characters
traits that serve a similar function but have separate evolutionary origins, a result of convergent
evolution. Ex: bird and bat wings.
Convergent evolution
similarity between species in certain traits that is caused by similar, but evolutionary independent,
responses to common environmental problems.
Homoplasy
similarity in the characters found in different species NOT inherited from a common ancestor. Ex:
cacti and euphorbs
Parallel evolution
similar phenotypes arise form similar developmental origins in different species. Ex: attachment
organs in larval stages of blind cave fish
Taxon (taxa)
any group of species that we designate or name (like vertebrates)
Clade
a taxon that consists of all the descendants of a common ancestor
Vertebrate clade
having an embryo that develops within an amnion (an adaptation to laying eggs on land) includes
reptiles, birds, and mammals
General events leading to speciation
populations become isolated physically, beahviorally, etc; populations diverging in 1+ traits (mating
behavior, etc); reproductive isolation
Why do rates of speciation vary?
habitat specialization, diet specialization, changes in ploidy
Ploidy
, an organism doubling their own chromosome number or being fertilized by another species and
then doubling chromosome number
2 commonly recognized modes of speciation
Allopatric and Sympatric
Allopatric Speciation
among populations with discontinuous distributions; dispersal, peripatric, and vicariance
Allopatric dispersal
new populations established in area and subjected to unique selective pressures
Peripatric
small isolated population drifts to become reproductively isolated
Vicariance
existing populations divided by physical barriers, ex: snapping shrimp in Panama
Sympatric Speciation
among populations with overlapping distributions; reproductive isolation must occur without
geographic isolation
Migration
Physical movement from one area to another and back again; allows organisms to track resources
and habitat quality; carries risks of predation and starvation; may be under genetic control (like
Monarch butterflies)
Dispersal
The one-way movement of an individual from the natal area; results in gene flow if dispersers breed
in new habitat; introduces mortality risk associated with movement
Natal dispersal
Moving away from where born prior to reproduction; may be independent of environmental
conditions, thus minimizing the probability of inbreeding (ex: male belding's ground squirrels leaving
after reaching a certain weight)
Pre-saturation dispersal
occurs before resources become sparse
Saturation dispersal
the dispersal to avoid the shortage of important resources such as food or nest sites
Phylopatry
the lack of dispersal; organisms mature in the habitat in which they were born
Polyandry
