BSC 2011 Final Exam 4 Learning
Objectives Questions with All Actual
Answers 2026-2027 Updated.
List biotic and abiotic factors that limit the distribution and abundance of organisms, in both
terrestrial and aquatic ecosystems - Answer Abiotic Factors: sunlight, temperature, rain, wind,
soil, moisture levels, salinity, light, pH
Biotic Factors: predation, competition, parasitism, mutualism (producers, consumers,
decomposers)
Recognize that temperature and water levels are the abiotic factors that most influence
distribution of the major terrestrial biomes, and describe how temperature and water levels
vary with latitude and topography - Answer Temperature and water levels affect the
distribution of the major terrestrial biomes the most
Temperature - Answer *Temperature*: most animals are ectotherms, meaning they get their
metabolism from the outside environment; organisms typically function best within a specific
range of environmental temperature
-temperatures outside that range may force some animals fo expend energy regulating their
internal temperature (such as mammals and birds)
-low temp: water freezes; free plants
-high temp: denature proteins
*Latitude*: temperatures are typically warmer approaching the equator and cooler approaching
the poles
Driest area is 30 degrees north and south - more sunlight, less rainfall
*Topography*: Temperature decreases in height; highest temperatures at low altitudes and
lower temperatures at higher altitudes
How water influences the distribution of the major terrestrial biomes - Answer *Water*: if
water levels are too low, species that live at the seashore or in tidal wetlands can desiccate as
the tide recedes
-*affects the ability to obtain and conserve water*
-*organisms restricted to freshwater or saltwater habitats by limited ability for osmoregulation*
-affects oxygen concentration; can limit cellular respiration and other physiological processes
, lack of water: desiccation
excess water: drowns plants and other organisms
Describe how temperature limits the ranges of organisms at different
time scales - Answer Temperature: organisms typically function best within a specific range of
environmental temperature,
so temperatures that fall outside that range will force organisms to expend their energy and
limit their movement to areas that have their optimal temperature
Affects biological processes such as *cellular respiration, enzymatic activity and CaCO3
precipation*
Describe how water levels limit the range of organisms at different time scales - Answer
Water: lack of water can cause desiccation in animals that depend on water for survival and too
much water can quickly drown the organisms
Oxygen: depends on the amount of water available in the aquatic environment; very low in
deep ocean ad deep lake waters where organic matter is abundant
Salinity: affects the water balance of organisms through osmosis; most organisms are restricted
to either freshwater or saltwater habitats by their limited ability to osmoregulate
Describe how sunlight limits the ranges of organisms at different time scales - Answer
Sunlight: provides energy that drives most of the ecosystem, and lack of sunlight can limit the
distribution of photosynthetic species;
too much light can limit survival by damaging DNA and proteins, can prevent trees from
surviving above a certain level
-in aquatic systems, photosynthesis occurs only in the top of the water due to the position of
the sun
Describe how geographic barriers limit the ranges of organisms at different time scales - Answer
Geographic disturbances limits movement
*Barriers to dispersal affect ranges (continents or oceans could be in the way)*
Distribution patterns are caused by *current climate*, *evolutionary history* and *dispersal*
Objectives Questions with All Actual
Answers 2026-2027 Updated.
List biotic and abiotic factors that limit the distribution and abundance of organisms, in both
terrestrial and aquatic ecosystems - Answer Abiotic Factors: sunlight, temperature, rain, wind,
soil, moisture levels, salinity, light, pH
Biotic Factors: predation, competition, parasitism, mutualism (producers, consumers,
decomposers)
Recognize that temperature and water levels are the abiotic factors that most influence
distribution of the major terrestrial biomes, and describe how temperature and water levels
vary with latitude and topography - Answer Temperature and water levels affect the
distribution of the major terrestrial biomes the most
Temperature - Answer *Temperature*: most animals are ectotherms, meaning they get their
metabolism from the outside environment; organisms typically function best within a specific
range of environmental temperature
-temperatures outside that range may force some animals fo expend energy regulating their
internal temperature (such as mammals and birds)
-low temp: water freezes; free plants
-high temp: denature proteins
*Latitude*: temperatures are typically warmer approaching the equator and cooler approaching
the poles
Driest area is 30 degrees north and south - more sunlight, less rainfall
*Topography*: Temperature decreases in height; highest temperatures at low altitudes and
lower temperatures at higher altitudes
How water influences the distribution of the major terrestrial biomes - Answer *Water*: if
water levels are too low, species that live at the seashore or in tidal wetlands can desiccate as
the tide recedes
-*affects the ability to obtain and conserve water*
-*organisms restricted to freshwater or saltwater habitats by limited ability for osmoregulation*
-affects oxygen concentration; can limit cellular respiration and other physiological processes
, lack of water: desiccation
excess water: drowns plants and other organisms
Describe how temperature limits the ranges of organisms at different
time scales - Answer Temperature: organisms typically function best within a specific range of
environmental temperature,
so temperatures that fall outside that range will force organisms to expend their energy and
limit their movement to areas that have their optimal temperature
Affects biological processes such as *cellular respiration, enzymatic activity and CaCO3
precipation*
Describe how water levels limit the range of organisms at different time scales - Answer
Water: lack of water can cause desiccation in animals that depend on water for survival and too
much water can quickly drown the organisms
Oxygen: depends on the amount of water available in the aquatic environment; very low in
deep ocean ad deep lake waters where organic matter is abundant
Salinity: affects the water balance of organisms through osmosis; most organisms are restricted
to either freshwater or saltwater habitats by their limited ability to osmoregulate
Describe how sunlight limits the ranges of organisms at different time scales - Answer
Sunlight: provides energy that drives most of the ecosystem, and lack of sunlight can limit the
distribution of photosynthetic species;
too much light can limit survival by damaging DNA and proteins, can prevent trees from
surviving above a certain level
-in aquatic systems, photosynthesis occurs only in the top of the water due to the position of
the sun
Describe how geographic barriers limit the ranges of organisms at different time scales - Answer
Geographic disturbances limits movement
*Barriers to dispersal affect ranges (continents or oceans could be in the way)*
Distribution patterns are caused by *current climate*, *evolutionary history* and *dispersal*
