BYU BIO 250 (Exam 2) UPDATED ACTUAL Questions and
CORRECT Answers
Relative Fitness The reproductive success of an individual genotype compared to other
genotypes in the population.
What obstacles are there to passing on genes? (agents of 1. Survival
selection) 2. Reproduction
examples of agents of selection 1. Predators
2. climate
3. disease
4. competition
5. mate availability.
Examples of survival obstacles 1. finding food
2. Predators/parasites
3. environment
4. compete/cooperate with others
5. protection from elements
Examples of Reproduction obstacles 1. Finding a mate
2. energy to reproduce
3. Offspring care
4. compilations
5. defend making territory
Putative adaptation A trait that appears to be an adaptation but needs testing.
The 4 types of studies 1. Observation Study / Natural Experiment
2. Controlled Experiment
3. Comparative Methods
4. Computer Simulation
Observation Study / Natural Experiment ✅ Pro: Can be done on humans
❌ Con: Confounding variables
Controlled Experiment ✅ Pro: Controls confounding variables
❌ Con: Limited in human studies
Comparative Methods Comparing species (e.g. bat study).
✅ Pro: Uses data from many species
❌ Con: Less focused on mechanisms
Computer simulation Can be insightful but not always reliable.
✅ Pro: Useful when real experiments are hard
❌ Con: Not always reliable (based on assumptions)
, Understand the Human Adaptation to High Elevation Comparative study
Compares different human populations (Tibetans, Andeans, Ethiopians)
Identifies different evolutionary solutions to the same environmental stressor
(low oxygen)
Understand fly wings experiment Controlled Experiment
Researchers manipulated wing markings
Measured predator responses under controlled conditions
bat experiment Comparative Method
Compared many bat species with different mating group sizes
Found a pattern between group size and testes size
phenotypic plasticity The ability of one genotype to produce multiple phenotypes when exposed to
different environments
Human birth tradeoffs 1. Bipedalism → narrower pelvis
2. Big-brained babies → larger skulls
3. Result = Tight fit, leading to complicated labor, higher risk of death, and a
need for help during delivery
Constraints on adaptation 1. Phylogenetic
2. Developmental
Phylogenetic constraints Limited by ancestral traits (e.g., humans can't lay eggs). ["yesterday's adaptation is
today's constraint"]
Developmental constraints Limitations on future evolution pathways that come from developmental pathways
and major body plans. Some adaptations can't evolve due to how organisms
develop.
What are the strategies for asking interesting evolutionary 1. What is the adaptation?
medicine questions? 2. What is the selective agent?
3. What tradeoffs are involved?
4. Is it a mismatch with the current environment?
Ask what the adaptation is What trait is helping the organism survive or reproduce?
Ask what the selective agent is What is the pressure or threat causing the adaptation? (e.g., pathogen,
environment, competition)
Ask about the tradeoffs Does the adaptation cause any problems or costs elsewhere?
Ask if there’s a mismatch is the trait still helpful today, or is it left over from a past environment that no
longer fits?
CORRECT Answers
Relative Fitness The reproductive success of an individual genotype compared to other
genotypes in the population.
What obstacles are there to passing on genes? (agents of 1. Survival
selection) 2. Reproduction
examples of agents of selection 1. Predators
2. climate
3. disease
4. competition
5. mate availability.
Examples of survival obstacles 1. finding food
2. Predators/parasites
3. environment
4. compete/cooperate with others
5. protection from elements
Examples of Reproduction obstacles 1. Finding a mate
2. energy to reproduce
3. Offspring care
4. compilations
5. defend making territory
Putative adaptation A trait that appears to be an adaptation but needs testing.
The 4 types of studies 1. Observation Study / Natural Experiment
2. Controlled Experiment
3. Comparative Methods
4. Computer Simulation
Observation Study / Natural Experiment ✅ Pro: Can be done on humans
❌ Con: Confounding variables
Controlled Experiment ✅ Pro: Controls confounding variables
❌ Con: Limited in human studies
Comparative Methods Comparing species (e.g. bat study).
✅ Pro: Uses data from many species
❌ Con: Less focused on mechanisms
Computer simulation Can be insightful but not always reliable.
✅ Pro: Useful when real experiments are hard
❌ Con: Not always reliable (based on assumptions)
, Understand the Human Adaptation to High Elevation Comparative study
Compares different human populations (Tibetans, Andeans, Ethiopians)
Identifies different evolutionary solutions to the same environmental stressor
(low oxygen)
Understand fly wings experiment Controlled Experiment
Researchers manipulated wing markings
Measured predator responses under controlled conditions
bat experiment Comparative Method
Compared many bat species with different mating group sizes
Found a pattern between group size and testes size
phenotypic plasticity The ability of one genotype to produce multiple phenotypes when exposed to
different environments
Human birth tradeoffs 1. Bipedalism → narrower pelvis
2. Big-brained babies → larger skulls
3. Result = Tight fit, leading to complicated labor, higher risk of death, and a
need for help during delivery
Constraints on adaptation 1. Phylogenetic
2. Developmental
Phylogenetic constraints Limited by ancestral traits (e.g., humans can't lay eggs). ["yesterday's adaptation is
today's constraint"]
Developmental constraints Limitations on future evolution pathways that come from developmental pathways
and major body plans. Some adaptations can't evolve due to how organisms
develop.
What are the strategies for asking interesting evolutionary 1. What is the adaptation?
medicine questions? 2. What is the selective agent?
3. What tradeoffs are involved?
4. Is it a mismatch with the current environment?
Ask what the adaptation is What trait is helping the organism survive or reproduce?
Ask what the selective agent is What is the pressure or threat causing the adaptation? (e.g., pathogen,
environment, competition)
Ask about the tradeoffs Does the adaptation cause any problems or costs elsewhere?
Ask if there’s a mismatch is the trait still helpful today, or is it left over from a past environment that no
longer fits?
