Behavior and Genetics Flashcards
Comparison of monozygotic versus dizygotic twins, each raised in the same household
Tries to distinguish between nature and nurture for a trait
Classical twin study
Monozygotic vs dizygotic twins
Monozygotic: identical twins from one egg, have 100% the same genes
Dizygotic: fraternal twins from two eggs, share 50% of genes
Problems with twin studies
Identical twins are treated more similarly than fraternal twins, meaning that monozygotic twins have more similar environments compared to dizygotic twins
Adopted child is compared to biological family and adopted family, allowing researchers to assess influence of nature versus nurture
Adoption studies
Strong genetic component findings of twin and adoption studies
Identical twins are more similar, fraternal twins are not
Identical twins raised together or apart have the same findings (meaning environment has little influence)
Adopted child findings more similar to biological than adoptive parents
Strong environmental component findings of twin and adoption studies
Identical twins and fraternal twins have similar outcomes
Identical twins raised together have similar findings, whereas identical twins apart have divergent findings
Adopted child findings more similar to adoptive than bioloigical parents
Behavior traits that are not present at birth but are acquired through experience with the environment
Learned behavior
4 Characteristics of learned behavior
Non-inherited: acquired through observation and experience
Extrinsic: will be absent if organism is isolated
Permutable: can be changed through experience
Progressive: can change and improve over time
Examples of learned behavior:
Learning to read
Dog fetching a ball
Function of behavior
To maintain homeostasis (equilibrium)
The extent to which a trait or behavior aids survival and/or reproduction
adaptive value
A field of study that focuses on the observation of animal behaviors
ethology
Individual units of heredity
Specific segments of DNA
genes
Traits that are linked to specific genes, like eye or hair color
Follow Mendelian monogenetic inheritance patterns
Interact minimally with environment
simple traits
Traits that are associated with groups of genes, like intelligence
Follow Mendelian polygenic inheritance patterns
Subject to greater environmental influence
complex traits
Temperament vs personality
Temperament is one’s innate tendency toward certain characteristics
Personality is a collection of characteristics believed to be constant over one’s lifetime
Estimates the amount of variance of a trait that can be attributed to genes in specific subgroups of individuals
Heritability
For example, stating that intelligence (trait) has a heritability of 50% means that 50% of the difference in intelligence is accounted for by genes, NOT that intelligence is 50% genetic
Specific to the population being studied, and is NOT a broad estimate of nature vs nurture in a general population
Genetically programmed behavior, present from birth, that requires no experience with the environment
Innate behavior
4 Characteristics of innate behavior
Inherited: genetically programmed rather than learned
Intrinsic: present even if organism is isolated, does not require being taught
Stereotypic: performed the same way every time
Consummate: Fully developed, does not change with experience or environment
Examples of innate behavior:
Urination, defecation
Birds migrating at the same time every season
Shivering when cold
Three main types of innate behavior
Reflexes = sensory and motor nerve loop response
Orientation behaviors = kinesis (undirected change in movement, like a change in speed) and taxis (directed change in movement, such as moving closer or further from a stimulus)
Fixed-action patterns = series of coordinated actions triggered by a key stimulus; similar to a reflex but more complex. Example: praying mantis strike manuever when encountering prey
Types of behavior
- Innate behavior
Inherited behavior that is genetically programmed and does not change through experience - Learned behavior
Acquired behavior that develops and changes with experience - Complex behavior
Combination of innate and learned behavior
Requires a relationship between genes and environment in adaptation
Example: Ability of humans to jump. All humans innately know this behavior, but through practice and adaptation can improve it - Covert behavior
Behaviors that are not observable
Example: Ability of humans to dream
Use of genetic methods to investigate the nature and origins of individual differences in behavior
behavioral genetics
Passing of traits from parents/ancestors to offspring through genes
heredity
Distinguishing qualities and characteristics of individuals
traits
Qualities that are passed from parents to offspring, such as eye color, hair color, and height
inherited traits
Learned traits that come from environmental factors, such as temper or happiness
Acquired traits
