Bio 226 Final Exam Questions And
Correct Answers.
3 limiting factors influencing population growth/ logistic growth? - Answer 1) Biotic Potential-
population is growing at maximum rate means it is growing at its biotic potential
2) Environmental Resistance-
sooner or later environment becomes less than ideal- food becomes limited, large # of
individuals start to spread disease or crowd one another, not enough space for nesting or
territories.
Death rates increase and/or birth rates decrease.
3) Density-dependent population growth - growth depends on density of population - more
crowding → lower population growth
Density dependent factors:
Resources
Disease
Predation
Physiological factors
(and density-independent - unpredictable)
Pre-zygotic isolating barriers - Answer Pre-zygotic:
1. Reproductive isolation- before zygote formation, parents are separated by barrier, and no
longer realize their desired mates.
2. Lock-and-key (mechanical)- structural differences in copulatory organs may prevent sperm
from being transferred from one species to another
3. Behavioral isolation - Many species have distinct courtship behaviors - individuals mate only
with individuals that display correct courtship behavior
4. Gametic isolation - gametes do not form a zygote because of incompatibilities preventing
fusion - external fertilizers - pollen recognition
5. Habitat isolation or ecological separation - species that breed in different parts of their
habitat are unlikely to encounter each other
6. Temporal isolation- Two species that breed during different times of the day, seasons, or
years
Post-zygotic barriers - Answer 1. Allopatric speciation - populations of a single species become
, 2. Peripatetic speciation
Dispersal:
3. Sympatric speciation: 4. By-product speciation - New species arise within the range of the
parent populations-- requires strong disruptive selection - Reduced gene flow
Reinforcement & Speciation
5. By-product speciation - in isolation natural selection and or drift operate
6. hybrid inviability
Exponential and Logistic Growth formulas - Answer Exponential:
G=rN
Logistic:
G= rN(K-N/K)
r= per capita rate of increase
N= number of individuals present at given time
K= carrying capacity
Plant challenges from moving from aquatic to terrestrial environment - Answer 1. Maintaining
moisture
2. Obtaining resources from air and soil
3. Support
4. Reproduction/dispersal
Plant adaptations from aquatic to terrestrial environment - Answer 1. stems & leaves covered
by cuticle (minimize water loss). Evaporation controlled by opening & closing stomata
(openings)
2. they evolved specialized organs to obtain resources from soil & air: roots, stems, leaves,
apical meristems. xylem- water and nutrient transport, phloem- sugar distribution
3. lignin- a complex organic polymer deposited in the cell walls of many plants, making them
rigid and woody
4. alternation of generations
Sporangia- meiosis to produce spores, Gametangium, archegonium, antheridium
sporophytes→ produce & release spores from the sporangia tissue
Correct Answers.
3 limiting factors influencing population growth/ logistic growth? - Answer 1) Biotic Potential-
population is growing at maximum rate means it is growing at its biotic potential
2) Environmental Resistance-
sooner or later environment becomes less than ideal- food becomes limited, large # of
individuals start to spread disease or crowd one another, not enough space for nesting or
territories.
Death rates increase and/or birth rates decrease.
3) Density-dependent population growth - growth depends on density of population - more
crowding → lower population growth
Density dependent factors:
Resources
Disease
Predation
Physiological factors
(and density-independent - unpredictable)
Pre-zygotic isolating barriers - Answer Pre-zygotic:
1. Reproductive isolation- before zygote formation, parents are separated by barrier, and no
longer realize their desired mates.
2. Lock-and-key (mechanical)- structural differences in copulatory organs may prevent sperm
from being transferred from one species to another
3. Behavioral isolation - Many species have distinct courtship behaviors - individuals mate only
with individuals that display correct courtship behavior
4. Gametic isolation - gametes do not form a zygote because of incompatibilities preventing
fusion - external fertilizers - pollen recognition
5. Habitat isolation or ecological separation - species that breed in different parts of their
habitat are unlikely to encounter each other
6. Temporal isolation- Two species that breed during different times of the day, seasons, or
years
Post-zygotic barriers - Answer 1. Allopatric speciation - populations of a single species become
, 2. Peripatetic speciation
Dispersal:
3. Sympatric speciation: 4. By-product speciation - New species arise within the range of the
parent populations-- requires strong disruptive selection - Reduced gene flow
Reinforcement & Speciation
5. By-product speciation - in isolation natural selection and or drift operate
6. hybrid inviability
Exponential and Logistic Growth formulas - Answer Exponential:
G=rN
Logistic:
G= rN(K-N/K)
r= per capita rate of increase
N= number of individuals present at given time
K= carrying capacity
Plant challenges from moving from aquatic to terrestrial environment - Answer 1. Maintaining
moisture
2. Obtaining resources from air and soil
3. Support
4. Reproduction/dispersal
Plant adaptations from aquatic to terrestrial environment - Answer 1. stems & leaves covered
by cuticle (minimize water loss). Evaporation controlled by opening & closing stomata
(openings)
2. they evolved specialized organs to obtain resources from soil & air: roots, stems, leaves,
apical meristems. xylem- water and nutrient transport, phloem- sugar distribution
3. lignin- a complex organic polymer deposited in the cell walls of many plants, making them
rigid and woody
4. alternation of generations
Sporangia- meiosis to produce spores, Gametangium, archegonium, antheridium
sporophytes→ produce & release spores from the sporangia tissue
