EEB 2244 STUDY EXAMS GUIDE ALL SET QUESTIONS
AND ANSWERS SURE A+
✔✔independent assortment - ✔✔during meiosis homologous chromosomes separate
randomly
✔✔Recombination (crossing over) - ✔✔homologous chromosomes overlap during
metaphase, exchanging nucleotides.
✔✔Macroevolution - ✔✔species level or higher
✔✔microevolution - ✔✔populations
✔✔selection - ✔✔a natural or artificial
✔✔random processes - ✔✔mutations, genetic drift, founder effects, bottlenecks
✔✔natural selection - ✔✔1. Not all offspring survive to reproduce
2. Population has heritable variation
3. Change in the environment causes a change in selection pressures
4. A phenotype determined by a certain allele(s) becomes favorable
5. Organisms with that allele are more likely to survive and reproduce.
,6. Next generation offspring are more likely to have that allele → more common in the
population
✔✔directional selection - ✔✔Individuals at one extreme are disadvantaged
Frequency curve shifts in direction of favored phenotype
Mean (average) value of the phenotype changes
✔✔stabilizing selection - ✔✔Intermediate phenotype favored
Curve becomes thinner, taller: decreased variation
Removes harmful genetic variation
Also when environment is relatively unchanging
✔✔disruptive selection - ✔✔Individuals at both extremes favored
relatively uncommon
increases phenotypic variation
can lead to biological speciation
✔✔Mutations - ✔✔neutral, harmful or beneficial
✔✔genetic drift - ✔✔random fluctuations in a gene pool over time can cause variation to
be lost. Important in small populations.
✔✔bottleneck effect - ✔✔a reduction in the genetic diversity of a population caused by
a reduction in its size
✔✔founder effect - ✔✔small number of colonizers start new population with small
amount of genetic variation
✔✔species - ✔✔Group of organisms that naturally interbreed with each other and
produce fertile offspring
✔✔allopatric speciation - ✔✔The evolution of new species due to geographic isolation.
Most common mechanism of speciation
Many (not all) of Darwin's finches
✔✔sympatric speciation - ✔✔Evolution of new species without geographic isolation.
Can be caused by small-scale habitat variation, resource diversity
✔✔polyploid - ✔✔an organism that has 3+ sets of chromosomes (homologous
chromosomes fail to separate during meiosis producing a diploid gamete)
Genetically distinct from parents
Unable to breed with a diploid
Can cause sympatric speciation.
✔✔stressors in terrestrial systems - ✔✔water, heat, cold, nutrients and food
,✔✔water stress - ✔✔conserve, store, tolerate dehydration
✔✔conserve - ✔✔Eliminating salts and other toxins (NH3 ) often involves water intake
and urine excretion
Water loss is reduced through: Production of concentrated urea or uric acid (containing
NH3 )
Specialized kidneys and other salt-excreting organs
Water acquisition and transport Driven by evapo-transpiration through stomata -
Cohesion and tension "pull" water through plant
Water loss can be minimized by closing or sheltering (underneath hair or in pits)
stomata
✔✔role of soils - ✔✔Water availability impacted soil properties
Smaller particles → more surface area→ more water held
− Small: more held, but tightly
− Large: loosely held, but less
Soils with a good mix often best for plants: − Loam: 40% sand, 40% silt, 20% clay
✔✔tolerate: water - ✔✔Tolerating air embolisms in dry environments can help plants
survive
Smaller leaves with more major veins reduce the impact of air embolisms
✔✔alternate pathways for photosynthesis - ✔✔C3 photosynthesis (most plants): Use of
Rubisco → energy loss when stomata are closed → need to keep open more often.
Not good in hot, dry environments
C4 & CAM photosynthesis increase water-use efficiency: Different enzyme: PEP
(Phosphenol pyruvate), Separate photosynthesis into different cells (C4) or different
times of the day (CAM)
✔✔store - ✔✔Storing water for a "non-rainy day" can be an important adaptation in dry
environments
✔✔heat stress - ✔✔reduce input/evade, dissipate, tolerate
✔✔dissipate - ✔✔Increasing surface area → increased exchange of heat energy with
the environment
✔✔Bergmann's Rule - ✔✔smaller size organisms in warmer environments at lower
latitudes (higher surface area to volume ratio)
✔✔tolerate: heat - ✔✔Antelope squirrel can tolerate body temps to 104 °F (40 °C)!
✔✔homeotherm - ✔✔constant body temperature
, ✔✔Poikilotherm - ✔✔variable body temperature
✔✔cold stress - ✔✔hibernation, food storage, insulate, tolerate
✔✔nutrient stress - ✔✔root structure, active transport
Fungal and bacterial associates aid in nutrient acquisition (typically in exchange for
carbon products)
✔✔tolerate: cold - ✔✔Many amphibians can avoid tissue damage while "freezing solid"
Willow tit tolerates lower body temperatures at night (nocternal hypothermia)
✔✔hibernation - ✔✔Individuals reduce energetic costs by lowering heart rate and
decreasing body temperatures; common in mammals.
✔✔insulate - ✔✔Layers of fat and fur
✔✔food stress: storage - ✔✔Plants store carbohydrates in roots and stems
✔✔phenotype - ✔✔the observable traits of an individual organism: morphological,
physiological, behavioral, or phenological characteristics; may be fixed or variable and
discrete or continuous
✔✔phenotypic trade-off - ✔✔higher fitness is achieved by different phenotypes in
different environments
✔✔phenotypic plasticity responses - ✔✔Biotic variation (enemies, competition etc.) -
Abiotic variation (temperature, water, salt, oxygen etc.)
Rapid responses often reversible (behavior, physiological acclimation)
Slower responses (morphology, life history) often irreversible.
✔✔Plastic foraging behavior - ✔✔Different feeding strategies represent different
behavioral phenotypes.
Changes in diet composition, foraging locations, time spent foraging
✔✔Migration - ✔✔Seasonal movement from one region to another
Conditions so severe that individuals cannot acclimate (or necessary changes would be
too costly).
✔✔dormancy - ✔✔Reduce metabolism due to conditions that prevent normal
functioning
✔✔diapause - ✔✔partial or complete physiological shutdown
✔✔torpor - ✔✔brief period of dormancy to deal with cold conditions
AND ANSWERS SURE A+
✔✔independent assortment - ✔✔during meiosis homologous chromosomes separate
randomly
✔✔Recombination (crossing over) - ✔✔homologous chromosomes overlap during
metaphase, exchanging nucleotides.
✔✔Macroevolution - ✔✔species level or higher
✔✔microevolution - ✔✔populations
✔✔selection - ✔✔a natural or artificial
✔✔random processes - ✔✔mutations, genetic drift, founder effects, bottlenecks
✔✔natural selection - ✔✔1. Not all offspring survive to reproduce
2. Population has heritable variation
3. Change in the environment causes a change in selection pressures
4. A phenotype determined by a certain allele(s) becomes favorable
5. Organisms with that allele are more likely to survive and reproduce.
,6. Next generation offspring are more likely to have that allele → more common in the
population
✔✔directional selection - ✔✔Individuals at one extreme are disadvantaged
Frequency curve shifts in direction of favored phenotype
Mean (average) value of the phenotype changes
✔✔stabilizing selection - ✔✔Intermediate phenotype favored
Curve becomes thinner, taller: decreased variation
Removes harmful genetic variation
Also when environment is relatively unchanging
✔✔disruptive selection - ✔✔Individuals at both extremes favored
relatively uncommon
increases phenotypic variation
can lead to biological speciation
✔✔Mutations - ✔✔neutral, harmful or beneficial
✔✔genetic drift - ✔✔random fluctuations in a gene pool over time can cause variation to
be lost. Important in small populations.
✔✔bottleneck effect - ✔✔a reduction in the genetic diversity of a population caused by
a reduction in its size
✔✔founder effect - ✔✔small number of colonizers start new population with small
amount of genetic variation
✔✔species - ✔✔Group of organisms that naturally interbreed with each other and
produce fertile offspring
✔✔allopatric speciation - ✔✔The evolution of new species due to geographic isolation.
Most common mechanism of speciation
Many (not all) of Darwin's finches
✔✔sympatric speciation - ✔✔Evolution of new species without geographic isolation.
Can be caused by small-scale habitat variation, resource diversity
✔✔polyploid - ✔✔an organism that has 3+ sets of chromosomes (homologous
chromosomes fail to separate during meiosis producing a diploid gamete)
Genetically distinct from parents
Unable to breed with a diploid
Can cause sympatric speciation.
✔✔stressors in terrestrial systems - ✔✔water, heat, cold, nutrients and food
,✔✔water stress - ✔✔conserve, store, tolerate dehydration
✔✔conserve - ✔✔Eliminating salts and other toxins (NH3 ) often involves water intake
and urine excretion
Water loss is reduced through: Production of concentrated urea or uric acid (containing
NH3 )
Specialized kidneys and other salt-excreting organs
Water acquisition and transport Driven by evapo-transpiration through stomata -
Cohesion and tension "pull" water through plant
Water loss can be minimized by closing or sheltering (underneath hair or in pits)
stomata
✔✔role of soils - ✔✔Water availability impacted soil properties
Smaller particles → more surface area→ more water held
− Small: more held, but tightly
− Large: loosely held, but less
Soils with a good mix often best for plants: − Loam: 40% sand, 40% silt, 20% clay
✔✔tolerate: water - ✔✔Tolerating air embolisms in dry environments can help plants
survive
Smaller leaves with more major veins reduce the impact of air embolisms
✔✔alternate pathways for photosynthesis - ✔✔C3 photosynthesis (most plants): Use of
Rubisco → energy loss when stomata are closed → need to keep open more often.
Not good in hot, dry environments
C4 & CAM photosynthesis increase water-use efficiency: Different enzyme: PEP
(Phosphenol pyruvate), Separate photosynthesis into different cells (C4) or different
times of the day (CAM)
✔✔store - ✔✔Storing water for a "non-rainy day" can be an important adaptation in dry
environments
✔✔heat stress - ✔✔reduce input/evade, dissipate, tolerate
✔✔dissipate - ✔✔Increasing surface area → increased exchange of heat energy with
the environment
✔✔Bergmann's Rule - ✔✔smaller size organisms in warmer environments at lower
latitudes (higher surface area to volume ratio)
✔✔tolerate: heat - ✔✔Antelope squirrel can tolerate body temps to 104 °F (40 °C)!
✔✔homeotherm - ✔✔constant body temperature
, ✔✔Poikilotherm - ✔✔variable body temperature
✔✔cold stress - ✔✔hibernation, food storage, insulate, tolerate
✔✔nutrient stress - ✔✔root structure, active transport
Fungal and bacterial associates aid in nutrient acquisition (typically in exchange for
carbon products)
✔✔tolerate: cold - ✔✔Many amphibians can avoid tissue damage while "freezing solid"
Willow tit tolerates lower body temperatures at night (nocternal hypothermia)
✔✔hibernation - ✔✔Individuals reduce energetic costs by lowering heart rate and
decreasing body temperatures; common in mammals.
✔✔insulate - ✔✔Layers of fat and fur
✔✔food stress: storage - ✔✔Plants store carbohydrates in roots and stems
✔✔phenotype - ✔✔the observable traits of an individual organism: morphological,
physiological, behavioral, or phenological characteristics; may be fixed or variable and
discrete or continuous
✔✔phenotypic trade-off - ✔✔higher fitness is achieved by different phenotypes in
different environments
✔✔phenotypic plasticity responses - ✔✔Biotic variation (enemies, competition etc.) -
Abiotic variation (temperature, water, salt, oxygen etc.)
Rapid responses often reversible (behavior, physiological acclimation)
Slower responses (morphology, life history) often irreversible.
✔✔Plastic foraging behavior - ✔✔Different feeding strategies represent different
behavioral phenotypes.
Changes in diet composition, foraging locations, time spent foraging
✔✔Migration - ✔✔Seasonal movement from one region to another
Conditions so severe that individuals cannot acclimate (or necessary changes would be
too costly).
✔✔dormancy - ✔✔Reduce metabolism due to conditions that prevent normal
functioning
✔✔diapause - ✔✔partial or complete physiological shutdown
✔✔torpor - ✔✔brief period of dormancy to deal with cold conditions
