Intro to Behavior Flashcards
Logic of Darwin’s Reasoning?
Living organisms could increase their numbers geometrically, but they don’t (“struggle for existence”), variation exists among individuals in every species, inheritance, variations that result in greater survival and reproduction will increase in frequency over time
What does evolution not equal?
Natural selection
Evolution equals
gene or allele frequency change - mutation, migration, genetic drift, natural selection
Natural selection equals
differential genetic success “fitness”
Organisms are __________
Reproductively selfish
Animals behave in ways that enhance survival and reproduction of their…?
Own genetic material, even if it’s detrimental to population or species
Can behavior change over time?
Yes - behavioral evolution
Example of behavioral evolution
Oceanic field cricket had a change in wings and behavior. Longer and faster songs = higher parasitism rates… wing morphology changed and they became song absent… adopted new strategy of coming near crickets that were song present to find mates, but far enough away to not be seen by the parasitic fly
Lifetimes are sequences of….?
Unconscious cost/benefit decisions about how to maximize reproduction (i.e. behavior)
Evolution leads to new variants and/or change in frequencies of variants in the next generation. What are the new variant evolutionary forces and what are the change in frequency of variants evolutionary forces?
New variant evolutionary forces: Mutation & migration/gene flow
Change in frequency of variants evolutionary forces: Genetic drift & selection
Mutation
Random, most deleterious, new alleles
Mutation puts deleterious alleles in population and selection acts to remove them… mutation-selection balance
Migration/Gene flow
Homogenizes populations, movement of alleles from one population to another by movement of individuals or gametes. Will counteract differentiation (ex: local adaptation). It can both cause and prevent evolution
Genetic drift
Chance changes in allele frequencies, i.e. mortality, disease, predation, failure to mate, difference in offspring numbers, natural disaster. Unrelated to phenotypic variation. Small populations magnify genetic drift and it can oppose selection.
What evolutionary force is the only force that predictably leads to adaptation?
Natural selection
Should we think in terms of reproductive success or genetic success? Why?
Terms of genetic success because genetic success is exact description and always right. There are organisms that do not behave in ways that enhance their reproductive success.
List some examples of animals that do not favor reproductive success
Meiotic drive in fruit flies and honeybee workers
What are two ways to achieve genetic success?
Produce own offspring –> direct genetic benefits
Help relatives produce offspring –> indirect genetic benefits
What are replicators?
Entity which can be copied (genes, ideas, etc.), potentially immortal, information/software
What are vehicles?
The survival machines of replicators (plants, animals, etc.), tangible stuff/hardware, mere mortals
Selfish genes do not make _____
Selfish organisms
What are the two levels of questions?
Proximate and Ultimate
Proximate questions
Immediate cause questions - “how does behavior occur”
Ultimate questions
Long-term cause questions - “why does a behavior occur”
What are Tinbergen’s 4 types of questions?
Mechanistic, ontogenetic, functional, evolutionary
Mechanistic (Tinbergen’s first level of analysis)
How does it work physiologically, cognitively?
Ontogenetic (Tinbergen’s second level of analysis)
How does the behavior develop? What are the roles of genes and learning?
Functional (Tinbergen’s third level of analysis)
How has natural selection shaped the behavior? How does it effect fitness?
Evolutionary (Tinbergen’s fourth level of analysis)
How has the behavior evolved over time? What are the ancestral characters and how have they evolved?
Phylogenetic tree
A diagram showing relationships of ancestry and descent. Composed of lineages, lineages are composed of individuals of a species through time, individuals express characters
Character vs character-state examples
Character: song, larval activity, eye color parental care
Character-state: present/absent, low to high
Parsimony
The phylogenetic explanation for the character observations across taxa requiring the fewest number of changes
Homology
A trait that is possessed by two or more species that was inherited, with or without modification, from their common ancestor. Ex: short tail between bears, seals, and foxes
Analogy
Convergent trait. Traits that are similar in function but have independent origins. Ex: birds having courtship songs and crickets also having courtship songs
Strong inference (Platt)
Make multiple hypotheses to avoid attachment to a favored hypothesis and design an experiment to eliminate more or more alternative hypotheses
