evolution and psychology exam 1
What book by Thomas Malthus influenced both Darwin and Malthus in originating the notion of natural selection? What was its key argument? What role does this argument play in natural selection?
"An Essay on the Principle of Population" . Its key argument was that populations are going to grow faster than the resources needed to sustain them. Essentially this means that individuals are reproducing so rapidly that eventually they will outnumber their necessary resources to survive. Individuals that are better equipped to survive competition with resources will survive and reproduce. Key building block in the idea of natural selection ^
Natural selection
(differential reproductive success due to inherited variation among individuals) If A variation is better equipped to survive , then that gene variation will eventually dominate and take over. Only known mechanism that will produce the appearance of design in organisms
Mutation
(new genetic variation) Copying errors from generation to generation, results in new genetics and creates variation and change
Genetic drift
(random variations across generations) The sum of the random processes that result in change in gene frequencies from one generation to the next. Just randomness in sexually reproducing species. There's essentially random selection of subsets of the genetic complement from one generation to the next.
Describe three major gaps in Darwin's theory of evolution by natural selection as initially presented.
1. No theory of inheritance Darwin was aware there was inheritance, but did not know the process or how it actually happened 1B: because there was no theory of inheritance, there was no concept of mutation, the mechanism which introduces novel variation. Without novel variation increases in complexity on a macro-evolutionary time scale are difficult to envision Solution Mendelian genetics Described the process of inheritance Genes eye view 2. Cases of selfless/altruistic behavior Ex: Bees defending the hive Goes against survival of the fittest claim 3. Elaborate characteristics lacking in obvious function, and seemingly detrimental to survival Traits in the natural worlds that seem to promote death rather than survival
Define polymorphism.
2 or more alleles at a single locus. Closely related to sex. Sex overcomes cost by introducing variation in next generation. More than 1 variante of a gene. Biologists see that there is polymorphism everywhere in natural populations. Variation that is not related to function is a good thing because it helps cut off parasites
Gene-culture coevolutionary theory
3 assumptions The ability of humans to produce culture is a specific and evolved biological adaptation Since humans generate, acquire, modify , and transmit culture, this amounts to a second system of inheritance, and evolution running parallel to biological evolution The two inheritance systems (biological and cultural) interact: evolved psychological biases in learning and cognition shape the transmission of culture; while cultural change sets up new selective pressures causing genetic change. Culture is like the beaver's dam: it is both an expression of our natures and the environment in which we live
List the three criteria the Williams provided for identifying an adaptation? What are the requirements for identifying an adaptation, according to Tooby and Cosmides?
3 key criteria for identifying adaptations (Williams). Reliability: Regularly develops under normal conditions. Economy: Solves adaptive problem at low cost. Efficiency: Performs function well. (tooby and Cosmides) further criteria for an adaptation. Has many design features that are improbably well suited to solving and ancestral adaptive problem . These properties are unlikely to have arisen by chance. These features are not better explained as the byproduct of mechanisms designed to solve some alternative adaptive problem or some inclusive class of adaptive problem - carefully try to rule out the possibility of it being a by-product. Ex: see a mug, somebody proposes that it holds hot liquid, the other says its a paper weight, and another says its a pencil cup. We must identify the specific design features in order to determine its real purpose linked to a particular problem. Find out that it has heat retentive properties, arm for holding it to avoid heat
What is cryptic female choice?
A form of intersexual selection. Females can mate with more than one man; Occurs after copulation, females still have ways to avoid parenting with an unfavored male. Even if copulation occurs, it does not fully determine success for the male. After copulation, physical or anatomical barriers favor or disfavor the sperm of a male, and the female can alter her acidity levels to kill off the sperm. could also be abortion After birth, the female could show low or no maternal investment if she copulates with an unfavored male
What is a just-so story?
A plausible account of a trait's origin and function, but one that lacks conceptual rigor and that makes free if any falsifiable predictions. Not backed up by evidence
What is (properly) meant by the Environment of Evolutionary Adaptedness (EEA)?
A statistical composite of the set of dimensions of the environment relevant to an organism's ancestral environment. Trying to understand the environmental conditions that give rise to an adaptation. Properly, you want to recognize each adaptation as its own EEA, not a particular place and time. Set of selection pressures that create an adaptation
Explain inclusive fitness
AKA Kin Selection Because individuals who are likely to carry the same gene are genetic relatives, common ancestors. Reproduction that benefits not only ourselves but others who are having offspring in order to help promote the reproduction of the species. Introduce by William Hamilton. Solves the problem of altruism (organisms showing selfless behavior); Consequence of gene-centric thinking. Inclusive fitness = direct + indirect fitness. Fitness is influence by behaviors that boost one's own reproduction (direct fitness) and those that boost the reproduction of relatives (indirect fitness). Maximization of inclusive fitness is the purpose and process of natural selection
Fitness
About reproduction and the features that favor it. The propensity of an individual (or of individuals carrying a specific trait or allele) to produce viable offspring. Allele: a variant of a gene. The rate at which an allele spreads numerically. The ability to adapt to all possible future environments. The long-term future dynamics, or persistence, of the allele or trait in the population
What are the three end products of evolution? Be prepared to identify examples of each.
Adaptations: Inherited and reliably developing characteristics that emerged because they functioned to solve recurring ancestral problems, resulting in greater reproductive success. Emerge because they solve ancestral problems. By-products: Side-effects of adaptations; these did not emerge directly by virtue of improving reproductive success. Characteristic that does not directly increase reproductive success but is linked to a trait that does. Noise: Chance variation ; everything else, randomness. Ex: an umbilical cord is a necessary adaptation, it serves nutrients and what not to the unborn child. A by-product of the umbilical cord is the belly button, it serves no necessary function, but is there due to an adaptation. The shape and size of the belly-button, whether its an inny or an outie is all just noise, no rhyme or reason.
What is Hamilton's rule? Be prepared to apply it in practice.
Altruistic genes can become fixed when rb-c>0 (or rb>c). R = degree of relatedness. B = benefits to them (how much of a benefit the recipient of the help received). C = cost (how costly it will be for the helper to help). Determines when and if helping will pay off
What is a spandrel?
Architectural term, when you put arches together, there is a space in between, a by-product. It is used to call a by-product of natural selection
What late 19th century biologist refuted Lamarckism in a series of experiments? How did he do this?
August Weismann. He conceptualizes the idea of a "germ line". A germ line is essentially the sex cells and is where the transfer of adaptations/changes takes place and NOT through the physical body "soma". Information cannot be transmitted from soma to soma, only through germ line or germ plasma. He was able to prove this through the rat experiment of cutting off their tails to see if they would produce rats without tails
Theory 2: Gamete Competition Theory
Because proto-females produce large gametes to the exclusion of producing many gametes, they become relatively rare. This creates a selection pressure for proto-males to produce as many gametes as possible to out compete other proto-males.
Of the four great ape species, which has the largest breasts and penis as a proportion of body weight?
Chimps have the largest testes and human females have the largest breasts compared to body size
Identify the three major trade offs highlighted by life history theory.
Current vs. future reproduction, quantity vs. quality of offspring, mating vs. parenting effort
How does design by natural selection differ from design by engineering?
Design by engineering, the idea of design proposed by Paley, requires a conscious human designer. It contains a well thought out goal or vision Forward-looking Matches molds, intentions, desires, visions Can be deleted and started over High planning-to-tinkering ratio Design only responds to the contingencies that humans already know about, there is nothing created that hasn't been seen/done before Design by natural selection as proposed by Darwin No forward-lookingness No thought out plan, no conscious goal stated Plans cannot be scraped or started over Current designs are stuck with what they've inherited, only modifications of what is already there Natural processes Mindless process, small accumulation of changes over time
What are adaptations?
Design features that promote inclusive fitness that are a result of natural selection. Not all traits are adaptations. Every adaptation isn't "perfect" or "optimal". Evaluating whether a trait is an adaptation or not requires: A - specifying the recurrent selection pressures that putatively caused its evolution, B - exposing the claim of "good design" to serious attempts to falsify it. Design characteristics that would solve the problem
What is anisogamy?
Different sized gametes (sex cells). Disruptive selection cause 2 diff sizes. Questions why there are 2 sexes. Consequences: Males: small gametes, large numbers, energetically cheap. Females: large gametes, small numbers, energetically costly
directional selection
Drives a trait in a particular direction
How does the effect size for sex differences in human height compare to that for sex differences in human strength?
Effect size: a measure of the magnitude of the differences between two groups. Expressed in terms of standard deviation. Can be depicted as the overlap between two distributions (one for men and one for women). Men on average are 0.2 standard deviations taller than women. Choen's d of 2.0 in terms of strength differences between men and women
Mating vs. parenting effort
Effort used to raise offspring is not available for the production of additional offspring . Energy that is put into current offspring takes energy away from mating or into creating future offspring. Because of anisogamy, the optimum trade offs between mating effort and parenting effort are different for males and females. Optima can adjust depending on current fertility
Provide an example of a human trait that is thought to reflect each limitation of the adaptationist method
Environmental mismatch : Taste preferences for sugar, fat, salt amongst people were adaptive in the past. Result of a number of health conditions like obesity, caused by environments with surplus of these items. Evolution takes time, adaptations evolve over time and persist because of selection pressures in the past, if the environment changes, then there is a mismatch and struggles with adaptations in the new environment. Evolutionary constraints: Evolution can't do everything, hippos can't fly, we have inherited everything from the past, you cannot start from scratch
Stabilizing selection
Environmental pressures that keep the trait toward the average. Most common according to biologists. Filters out extreme variants that wont perform as well in the environment
Name two thinkers who, prior to Darwin, put forward evolutionary views.
Erasmus Darwin (darwin's grandfather) published Zoonomia; or the laws of Organic Life starting in 1794, along with other works that presage evolution. Jean-baptiste Lamark french naturalist published Philosophie Zoologie in 1809. Embraced evolution and even posited mechanisms for its occurrent , including the inheritance of acquired characteristics. Motivated to fit into its own environment. Ex: giraffe striving to get to tree, eventually leads to long neck
What are the major conceptual and methodological differences between Darwinian anthropology, evolutionary psychology, and gene-culture coevolutionary theory (see textbook)?
Evolutionary psychologists assert psychic unity of humankind due to biological evidence. Darwinian anthropologists disagree with "nurturists"; they believe that our evolutionary past has no bearing on our present condition. They believe that human behavior and the human mind are molded and conditioned largely by culture and that culture bears no relation to our genetic ancestry. Darwinian anthropologists suggest that current human behavior measured in terms of reproductive success shows signs of adaptiveness. Evolutionary psychologists argue that the correct Darwinian approach is to look for adaptations to ancestral environments that can now be identified with discrete problem solving modules in the brain. Gene-culture theorists examine the interaction between biological and cultural evolution.
Identify and explain two major hypotheses concerning why females might sexually selected traits in men, despite the survival disadvantages of those traits.
Fisher's "runaway" hypothesis, aka "sexy sons" , aka "good taste hypothesis". Females may mate with males with traits that are popular amongst most females in order to promote success in her lineage, even if the female does not particularly favor the trait herself. If her sons possess these same attractive traits, they are likely to attract many females and so on. Zahavi's "handicap" hypothesis, aka "Good genes" hypothesis, aka "costly signaling theory". Extravagant male traits that attract females are costly to develop and maintain. Females can detect males with "good genes" using an honest signal of genetic quality. Only males in good condition with good genes will be able to fully develop and maintain an ornament. Females must watch out for males who are faking these traits and therefore must try to look for males with the traits that cannot be faked and only the strongest maled with the best possible genes can afford to do that
What is lekking?
Form of polygyny. Males aggregate in particular areas called leks, and display for females. Male competition: males fight to be in the center of the lek . Female choice: females choose the most dominant male in the lek, usually the one in the center'. Might expect genetically related males to team up and dominate lek in order to promote reproductive success in their "family".
In laura Betzig's paper what societal form is characterized by the most extreme reproductive skew, and why?
Full-time farmers shows the most extreme reproductive skew. Because they have inherited wealth and land. Mass harem polygyny. Extreme competition amongst men. Dramatic reproduction skew among males. Emergence of agriculture on human reproduction for males, a lot of males are shut out of reproduction, consistent with rise of agriculture. Dark bars show difference between highest performing and lowest performing males and females in terms of reproduction
What is antagonistic pleiotropy?
Genes with beneficial effects in youth will persist even if they have very negative effects on health/condition at later ages
What three primate species are the closest relatives of humans?
Gorilla, chimpanzee, orangutan
What is group selection and how did George Williams largely convince biologists that selection occurs at the level of the gene and individual rather than the group or species? (Textbook should be useful here)
Group selection answers questions like "why does the bee defend the hive?" because it's for the good of the species. The idea is that a group-selectionist takes one for the team. If food supply is running low, an individual may hold off on reproducing to avoid the population crashing.Looking out for population, don't want food supply to run out, taking one for the team. Williams argues that if you look at the gene's eye view or an individual's view, this theory will not work. If there is a "mutant" that does not oblige to this selfless way of living, they are going to mooch off of all the resources for themselves and ruin the entire scenario. The reasons are not stable. Does not occur at species level
Identify and describe the three domains of investment, according to life history theory.
Growth and development: concerned with future reproduction. Skill acquisition, learning, practice, training. Somatic maintenance: also concerned with future reproduction. Maintaining the body - injury repair, immune system, keeping cells running. Reproduction: current reproduction. Resources devoted directly to making copies of one self - either mating or parenting
What was the importance of Charles Lyell's book Principles of Geology in the development of the theory of evolution?
He made it plausible that the earth is much older than what was originally thought
How did Darwin's observations of finches on the Galapagos Islands help convince him that species had evolved?
He saw widespread diversity among the different types of finches, but he found a deep anatomical and morphological connections to one continental variant, which provides evidence that they all come from one species and have since evolved.
explain tinbergen question 3. How has the behavior evolved (evolution or phylogeny)?
How is the behavior continuous with and different from similar behaviors in other species - including extinct species from which it may have developed. Concerned with our ancestors. Was there selective pressures amongst our ancestors that led to the emergence of a particular trait of behavior and we just inherited it over generations? Ex: color vision. Early primates developed color vision in order to distinguish colored fruits to see which was safe to eat. Ex: jealousy could be an adaptation of men's instincts derived from sperm competition, they want success of their sperm, which could lead to the development of jealousy to protect sperm and avoid the possibility of another males procreating with the female.
explain tinbergen question 2. How does the behavior come to develop in the individual (development or ontogeny)?
How the behavior arises during the process of development. How the behavior arises during the course of development of the individual organism through its lifespan. Brain development over time. Ex: first vs. second languages. Why is it so easy to learn our first language and then much more difficult to learn a second
Characterize the relative prevalence of these different mating systems across human cultures.
Humans are all of the above, for the most part. Across all time, polygyny is most common in humans. ½ of all studied there is slight polygynous societies - less than 20% of men have multiple wives. 30% of human societies participate in general polygyny - more than 20% of men have multiple wives. Only 16.7% of human societies are monogamous. Polyandry is the most rare. Only seen in about 1.1% of all human societies
Lorenz is known most for:
Imprinting: When a young animal will imprint on a first large animal it sees when born, usually a mother, lorenz demonstrated that animals can imprint on other animals, not just the mother. Fixed action patterns: a pattern of behavior that could be triggered by some external stimulus. Regarded these action patterns as instincts forged by natural selection and common to each member of a species. Contain characteristics such as: constant form (the same sequence of actions and the same muscles are used), they require no learning, they are characteristic of a species, they cannot be unlearned, they are released by a stimulus. Ex: a mother goose using the underside of her bill to roll an egg back into the nest when it falls out.
Polygamy
Individuals mate with more than one partner. Includes polygyny and polyandry
What mechanism for evolution was suggested by Lamarck?
Inheritance of acquired characteristics. During the life of an individual, they will be motivated to change to fit better into the environment and that change will be passed onto future generations/descendents
Identify and describe two kinds of sexual selection.
Intersexual selection: Mating success determined by between-sex interactions. ex) female choice of males (epigamic selection). Males evolve to make themselves more attractive, females evolve preferences. Female choice can be overt or cryptic. Typically intersexual selection is overt: the female selects a male based on preferences. Intrasexual selection: Mating succes determined by within-sex interactions. ex) male-male combat, sperm competition. Females just go with winner
Briefly summarize the major contributions to biology in the wake of Darwin made by William Hamilton
Introduces "inclusive fitness theory". Only major refinement of darwin's original theory: key limitation of Darwin's theory is that sometimes we observe organisms acting in an apparently selfless way, if it is supposed to be survival of the fittest, but we see bees sacrifice themselves in order to protect the hive
Tinbergen is best known for
Levels of causation. 4 questions. Student of Lorenz
Explain how Curtis Lively's experiments with C. elegans (in Morran et al., 2011) support the Red Queen hypothesis. Overall, which individuals exhibited the lowest mortality when exposed to co-evolved parasitic bacteria after multiple generations: obligate selfers, wild type, or obligate outcrossers?
Looks for evidence that parasite actions causes sexual reproduction. The red queen theory proposed that sexual reproduction happens to eliminate the succes of parasites passed into offspring. In a wild population containing C. elegans (roundworms), 20% reproduce sexually and 80% reproduce asexually. Conducted a study creating special populations of the worms, some that have to reproduce asexually, some sexually , and some wild-type (natural population). Control: no one exposed to parasite. Coevolution: repeated exposure of 30 generations to parasite. Evolution: repeated exposure to a fixed non evolving strain of parasite. The lowest mortality rate was the sexual reproduction groups. Most mortality when cloning takes place
what is the difference between proximate and ultimate explanations of behavior
MOST OF PSYCHOLOGY FOCUSES ON PROXIMATE EXPLANATIONS OF BEHAVIOR Proximate explanations of behavior try to identify factors that are very close to the behavior. Explanations very close to the behavior Looking for answers to "how" questions that identity forces often within the individual Can include environmental factors that trigger the behavior Plausible and developmental explanations Ultimate Explanations focus more on why functions/purposes of the future Survival and reproduction ancestry/distant past Forces on populations or groups of individuals What forces cause the feature to come to characterize the population of organisms?
Which sex typically has the lower variance in reproductive success: the lower-investing sex or the higher- investing sex?
Males are typically lower investing, while females are typically higher investing
Promiscuity
Males mate with more than 1 female and vice versa
What are 4 mechanisms that produce evolution?
Migration, mutation,natural selection, and genetic drift
What are the different mating systems?
Monogamy, polygyny, polyandry, promiscuity
Which one produces the appearance of complex design (adaptations)?
Natural selection
explain tingergen question 1. What are the mechanisms that cause the behavior (causation or mechanism) ?
Neural, hormonal, physiological, cellular mechanisms that give rise to behavior. What is the physiology that enables a behavior, what brain regions activate to make these behaviors? Ex: jealousy. What happens physically that makes a man jealous when he sees his wife in bed with another man, what is happening in his brain that triggers these emotions
Monogamy
One male mates exclusively with one female
Approximately what percent of mammalian species are monogamous?
Only about 3%
What is meant by the concept of "the selfish gene" as described by Dawkins?
Only genes survive to the next generation; they are true replicators. Your offspring are not exact copies of you, but they are exact copies of your genes and your mate's. Genes survive because they build parts of organisms the right way - a way that favors their own reproduction; hence the "selfish:
Quantity vs. quality of offspring
Parents have limited resources to invest. Many offspring = lower resources per offspring . The optimum is reached when the marginal increase in number of offspring produced equals the proportional increase in number of offspring that reach adulthood. This optimum is typically lower than the level that would ensure maximum offspring quality
What kind of adaptations does life history theory focus on?
Periodic growth and reproduction. Managing tradeoffs between different energy domains. Applied at level of the species, but do think about individual differences within individual people
Migration (gene flow)
Population of organism on an island are isolated, climate change happens and another species migrates over and mates and creates gene flow between the two species
Explain Gould and Lewontin's critique of adaptationism?
Published "The spandrels of san marco and the Panglossian Paradigm". Criticizes evolutionary biologists for coming up with adaptation explanations too easily. Accused people of considered by-products (spandrels) and traits with no evidence as adaptations
Briefly summarize the major contributions to biology in the wake of Darwin made by Richard Dawkins
Published the "Selfish Gene". Crystallizes the "gene-centric" view of life in which organisms are the vehicles of the propagation of the genes that build them. Idea that all of the natural world is a parade of machines contracted by genes in order to promote the replication of genes
Briefly summarize the major contributions to biology in the wake of Darwin made by George C. Williams
Publishes a book called "adaptation and natural selection". Provides criteria for was an adaptation is. Proposes that natural selection produces adaptations. Also refutes "group selection": the idea that traits emerge because they benefit the species as opposed to the individual . Traits emerge through evolution because of benefits to the individual, specifically the genes that build the individual
What is the coefficient of relatedness? Be able to identify the coefficient of relatedness for major types of relationships (e.g., full siblings, first cousins).
R = 0.5 between parents and offspring, and siblings. R = 0.25 between grandparents and grandchildren, uncles/aunts and nieces/nephews, and half siblings. R = 0.125 between 1st cousins . R = 0 between stepparents and step siblings
Why is sex an evolutionary puzzle?
Reproducing sexually has a lot of costs. The cost of males: if you're a gene in a female, you can be in all offspring (not half) through asexual reproduction. Cost of recombination: breaking up a winning design. Cost of mating: search costs, attracting a mate... Why would anyone want to reproduce sexually?
Who formulated the theory of parental investment, and what are its principles?
Robert trivers. Sexual selection is about a particular resources. Any investment by any parent in an individual offspring that increases the offsprings chances of survival and its reproductive success at the cost of the parents ability to invest in other offsprings. It goes beyond the current offspring, the parent is thinking about the potential future offspring. The main factor that drives variance between species is parental investment
Which is stronger: selection on traits expressed at a young age, or selection on traits expressed at an older age?
Selection traits at a younger age are stronger because there are more options to select from
How did Darwin conceive of sexual selection to be different from natural selection?
Sexual selection is distinguished from natural selection because sexual selection arises throguh variance in mating success. According to darwin they were distinct, Only sexual selection could product traits that compromise survival. The basic principles are identical - selection favors whatever gets more genes into the next generation.
What is sexual selection?
Sexual selection is the solution to problem #3. Darwin needed a theory to explain the many extravagant traits that seem to reduce survival . Measure of how spread out a distribution compared to the mean. Dives into another selection force. A mechanism in evolution that focuses on success in mating, not so much survival. "the descent of man and selection in relation to sex" by Darwin. In sexual selection fitness is measured relative to members of the same sex
Explain how testis size is related to primate mating structure.
Since larger testes means more sperm, this leads to multi-male competition for a single female, this creates sperm competition, so the males with the most sperm come out on top. Competitive edge over other species in terms of reproduction. promiscuous mating structure Gorillas on the other hand do NOT have the same mating structure due to their very tiny testes. Polygynist structure. A single male for multiple females. Not sperm competition, physical competition in fighting over females. Hence large upper bodies and small testes because there is no sperm competition once the male has won over a small group of females through physical competition.
What is the key finding reported by Laura Betzig in her analysis of reproductive skew in humans?
Societal form has a large impact on reproductive success in men and women
What is the fundamental difference between (human) sociobiology and evolutionary psychology?
Sociobiologists would generally examine human behavior on the assumption that people maximize inclusive fitness. Evolutionary psychologists examine human behavior on the assumption that it is the output of evolved psychological adaptations, which arose because they used information- processing procedures to solve ancestrally recurring adaptive problems. The difference is subtle but important. Although specific adaptations arose because they (on average) increased inclusive fitness under ancestral conditions, executing adaptations is not the same as maximizing current fitness.
Polygyny
Some males mates with multiple females. Harem polygyny: a bunch of females in close proximity, which leads to male-male competition in order to monopolizwe the entire area of female. Lekking polygyny
Theory 1: Gamete Limitation Theory
Some proto-female gametes will, by chance, fail to collide with proto-male gametes. These non-colliders will die. This creates a selection pressure for proto-males to produce as many gametes as possible to chase after unfertilized gametes
What is disruptive selection?
Somewhat rare, More extreme variants outperform individuals who are at an average level; very high or very low. If larger gametes represent or investment in offspring, where smaller gametes will benefit by fusing with larger ones. Though to have driven apart the two sexes
Explain William Paley's argument for design.
Special creation. Design of complex interrelated parts that work together. There must be some complex creator that leads to design
What is ethology?
Study of animal behavior under natural conditions, informed by natural selection (assumption that behavior is adaptive). Instead of bringing animals into labs to be studied, they are observed in their natural habitats and how they survive in those conditions. Ideas proposed by Konrad lorenz, nikolas tinbergen, and paul von frisch (all awarded nobel prize)
Fitness proxies
Substitutes that stand in for fitness
What is the operational sex ratio (see textbook)? What are the consequences of polygyny for the operational sex ratio, and how does this in turn affect male behavior?
Takes into account that although most mammals are roughly equal in numbers of males and females, not all males or females are sexually active and there may be local variations in ratios of sexes. Operational sex ratio = (fertilizable females) / (sexually active males). Consequences of polygyny for operational sex ratio are more intense male male competition
If a new primate species were discovered and exhibited a high degree of sexual size dimorphism in the upper body and had a mating structure much like that of gorillas, would we expect testis size as a proportion of body weight to be fairly large or fairly small?
Testes would be very small in comparison to the body because the large upper body portrays physical competition
What book is considered the manifesto of contemporary evolutionary psychology? What two psychologists are considered by many to be the founders, or the conceptual architects, of the field?
The Adapted Mind John Toobey and Leeda Cosmides
Explain the Red Queen Theory? Why is it called that?
The Red Queen is used as a metaphor for the coevolutionary arms race between host and parasite. Evolved host defenses against the parasite are offset by the parasites own evolution. Everyone is trying to get ahead by evolving and trying to be the best, Sex is a turbo boost, powerfull tool for hosts to used to try to get ahead. Parasites are always evolving; There are many both in terms of number and variety; They have much shorter generations times than their host, thus can evolve within a host. Parasites in a host are selected to exploit that particular hosts biochemistry. Hamilton states that sex gives individuals in the next generation an advantage to get rid or stop the parasite because it will have to readapt to new genetics
Define "evolution."
The change over time in a population, specifically changes in gene frequencies. Is to be distinguished from natural selection
From the perspective of life history theory, what is life?
The conversion of energy into offspring. Energy that ultimately comes from the sun and is converted in various ways
Cohen's D
The default effect sizes between groups . Expressed in standard deviations
When we take a gene's eye view of the natural world, how do we conceptualize individual organisms?
The genes are the replicators and process of selection needs to be extended down the the level of the gene. Many different kidneys of replicators in the genes
explain tinbergen question 4. What is the function or survival value of the behavior (function)?
The role the behaviors plays in how the species is adapted to its environment. What is the behavior doing to help a species and the individuals of the species adapt to its environment? How is it helping the individuals of a species reproduce and survive?
How does life history theory encompass, or relate to, parental investment theory?
They are completely consistent with each other. Parental investment theory is actually the application of life history theory to thinking about mating and parenting. Trivers said that parental investment theory is taking energy and devoting it to one offspring and not another with the idea of future offspring in mind
how can tinbergen's four whys be group by proximate and ultimate?
Tinbergen's four whys can be grouped into 2 groups, proximate and ultimate. Proximate: causation and development Ultimate: evolution and function
Explain how evolution by natural selection works. What are the three essential ingredients (or building blocks) of the process?
Variation: some copies are not exact replicas. Diversity in a population. Inheritance: replicators make copies of themselves. Specific variations of a species will only give birth to the same type. Differential reproduction aka selection: of the varieties produced, some survive and reproduce better than others. human selection drives the domestication of certain plants and animals to create a new species. If you have these three things, natural selection must occur. Natural selection is the only known process capable of design
How do the views of Alfred Russel Wallace relate to those of Charles Darwin when it comes to the relevance of evolution by natural selection for understanding the psychological capacities of humankind?
Wallace had the same ideas of Darwin that the relevance of evolution happens because of natural selection ...
Under what circumstances does polyandry tend to emerge?
When there are really really stark environments, resource poor. Resource gathering abilities are really important to sustain the offspring. Usually 1 women 2 men
Current vs. future reproduction
Why do we age? Extrinsic mortality. something in our environment will eventually kill the body. Selection is stronger on traits that are expressed at younger ages because more of the population is alive to be selected. Based on ancestral mortality rates, therefore our bodies have been designed to put less effort into rejuvenation if we are likely to die anyway
What is instinct blindness, and who first called attention to it?
William James first called attention to instinct blindness in Principles of Psychology. a side-effect of any instinct whose function is to generate some inferences or behaviors without simultaneously generating others. Being physically attracted to someone - automatic reactions, cant really be explained because of how unaware one is of it even happening. Later ev psychologists, say that the motivation of instinct blindness is there, but needs to be looked at deeper
Identify and explain two limitations of the adaptationist method, as noted by George Williams.
environmental mismatch and evolutionary constraints (not every adaptation is optimal).
According to Trivers, which sex will typically be choosier about mates, and why?
females
What were Tinbergen's 4 questions?
mnuemonic: ABCDEF: Animal Behavior, causation, development, Evolution, Function 1. What are the mechanisms that cause the behavior (causation or mechanism) ? 2. How does the behavior come to develop in the individual (development or ontogeny)? 3. How has the behavior evolved (evolution or phylogeny)? 4. What is the function or survival value of the behavior (function)?
Polyandry
some females mates with multiple males. Ex: jacanas exhibit harem oolyandry and "sex role reversal". Males perform all parental care . females mate with multiple males and leave eggs with males
