UA BSC Exam Study Guide 2025/2026 – Get Verified Questions &
Answers for Guaranteed Success! Graded A+ A Must Pass!!
What is micro-evolution? - Changes in allele frequencies within populations, often associated with
adaptation, can be measured from one generation to the next
"Small changes"
What is macro-evolution? - Major changes in the history of life, origin of new species, generates
biological diversity
"Big changes"
What is a species? - a group of populations whose members have the potential to interbreed with
one another in nature to produce fertile offspring
What is allopatric speciation? - Species evolve in geographic isolation, usually associated with a
geographic barrier that prevents members of 2 populations from mating with each other, involves
independent evolution of the populations after the barrier arises. "Physical separation"
What is sympatric speciation? - Species evolve without geographic isolation, probably associated
with a genetic barrier due to a single mutational event, important in plants. "Genetic separation"
What special circumstances are required to keep the gene pools separated in sympatric speciation? -
Segregation of habitat, major alterations in mate recognition or behaviour, genetic incompatibility
The two models of the Pace of Speciation - Gradualism-slow and steady accumulation of small
changes leads to production of species over vast stretches of time
Punctuated equilibrium-species diverge in spurts of rapid change, followed by long periods of stasis
What are prezygotic barriers? Know the 5 types - Prevent mating or fertilization between species. 5
types are: temporal isolation, habitat isolation, behavioural isolation, mechanical isolation, and
gametic isolation
Example of temporal isolation - Eastern and Western spotted skunks’ mate at different times of year,
preventing them from producing offspring even in areas where the two species live together
, Example of habitat isolation - Even though they occupy the same geographic area, these two species
of garter snakes occupy different habitats, preventing them from mating
Example of behavioral isolation - Blue footed boobies and many other animals use complex courtship
displays in selecting mates. Because other species cannot mimic these displays, offspring are not
produced with members of other species
Example of mechanical isolation - Snails of different species in the genus Bradybaena may attempt to
mate, but differences in the shapes of their shells prevent them from succeeding
Example of gametic isolation - Although the sperm and eggs of these two sea urchin species are
released into the water, they are unable to fuse because the proteins on the surface of the eggs and
sperm cannot bind to one another
What are postzygotic barriers? Know the 3 types - Prevent survival or reproduction of hybrid
offspring. 3 types are hybrid inviability (miscarriage), hybrid sterility (sterile offspring), and hybrid
breakdown(1st generation produces sterile/weak 2nd generation)
Example of hybrid inviability - Different salamander species sometimes mate, but the offspring fail to
complete development, keeping the gene pools of the two species isolated from one another
Example of hybrid sterility - Different species may mate, and produce viable offspring that are sterile,
preventing further mixing of gene pools. Mules are robust animals, offspring of a donkey and horse,
but they cannot reproduce
Example of hybrid breakdown (a post-zygotic barrier) - The first generation of hybrids may be both
viable and fertile, but due to genetic factors the offspring of these hybrids are weak, feeble, or
sterile, as in domesticated rice strains.
The 8 classification levels for naming a species - Domain, kingdom, phylum, class, order, family,
genus, species
The 8 classification levels for human beings - Domain: Eukaryota, Kingdom: Animilia, Phylum:
Chordata, Class: Mammalia, Order: Primates, Family: Hominidae, Genus: Homo, Species: sapiens
EACMPHHS
Answers for Guaranteed Success! Graded A+ A Must Pass!!
What is micro-evolution? - Changes in allele frequencies within populations, often associated with
adaptation, can be measured from one generation to the next
"Small changes"
What is macro-evolution? - Major changes in the history of life, origin of new species, generates
biological diversity
"Big changes"
What is a species? - a group of populations whose members have the potential to interbreed with
one another in nature to produce fertile offspring
What is allopatric speciation? - Species evolve in geographic isolation, usually associated with a
geographic barrier that prevents members of 2 populations from mating with each other, involves
independent evolution of the populations after the barrier arises. "Physical separation"
What is sympatric speciation? - Species evolve without geographic isolation, probably associated
with a genetic barrier due to a single mutational event, important in plants. "Genetic separation"
What special circumstances are required to keep the gene pools separated in sympatric speciation? -
Segregation of habitat, major alterations in mate recognition or behaviour, genetic incompatibility
The two models of the Pace of Speciation - Gradualism-slow and steady accumulation of small
changes leads to production of species over vast stretches of time
Punctuated equilibrium-species diverge in spurts of rapid change, followed by long periods of stasis
What are prezygotic barriers? Know the 5 types - Prevent mating or fertilization between species. 5
types are: temporal isolation, habitat isolation, behavioural isolation, mechanical isolation, and
gametic isolation
Example of temporal isolation - Eastern and Western spotted skunks’ mate at different times of year,
preventing them from producing offspring even in areas where the two species live together
, Example of habitat isolation - Even though they occupy the same geographic area, these two species
of garter snakes occupy different habitats, preventing them from mating
Example of behavioral isolation - Blue footed boobies and many other animals use complex courtship
displays in selecting mates. Because other species cannot mimic these displays, offspring are not
produced with members of other species
Example of mechanical isolation - Snails of different species in the genus Bradybaena may attempt to
mate, but differences in the shapes of their shells prevent them from succeeding
Example of gametic isolation - Although the sperm and eggs of these two sea urchin species are
released into the water, they are unable to fuse because the proteins on the surface of the eggs and
sperm cannot bind to one another
What are postzygotic barriers? Know the 3 types - Prevent survival or reproduction of hybrid
offspring. 3 types are hybrid inviability (miscarriage), hybrid sterility (sterile offspring), and hybrid
breakdown(1st generation produces sterile/weak 2nd generation)
Example of hybrid inviability - Different salamander species sometimes mate, but the offspring fail to
complete development, keeping the gene pools of the two species isolated from one another
Example of hybrid sterility - Different species may mate, and produce viable offspring that are sterile,
preventing further mixing of gene pools. Mules are robust animals, offspring of a donkey and horse,
but they cannot reproduce
Example of hybrid breakdown (a post-zygotic barrier) - The first generation of hybrids may be both
viable and fertile, but due to genetic factors the offspring of these hybrids are weak, feeble, or
sterile, as in domesticated rice strains.
The 8 classification levels for naming a species - Domain, kingdom, phylum, class, order, family,
genus, species
The 8 classification levels for human beings - Domain: Eukaryota, Kingdom: Animilia, Phylum:
Chordata, Class: Mammalia, Order: Primates, Family: Hominidae, Genus: Homo, Species: sapiens
EACMPHHS
