Lecture 9 Flashcards
How many years ago did life evolve?
3.5 billion (DNA replication was almost perfect)
How many years ago did sex evolve?
1.2 billion years ago (spread good genes and purged bad genes)
How many years ago did eyes evolve and why was it important?
543 million years ago. This was important because before eyes evolved, the result of life and sex was simple red green and brown algae. However, eyes allowed mate choice for fitness signals - this was when the Cambrian explosion of biodiversity happened. This resulted in weird looking organisms that we can’t explain other than for sexual choice. Evolution since the Cambrian explosion has been natural selection for efficient survival and sexual selection for conspicuous signals
Defines and discuss the costs and benefits fitness indicators
Because mutations continually erode fitness due to a complex adaptive design means we opt for mate choice that minimises mutations in offspring, by focusing on complex, informative traits called fitness indicators. In response, fitness indicators evolve to be ever more costly, complex, vulnerable and variable.
Fitness indicators allow someone to do something that a lower-fitness rival could not afford to do (in terms of energy, matter, time or risk). They do something that would make mutations, health problems and errors very conspicuous. They overcome difficulties to show your virtuosity.
The most informative fitness indicators show the highest variation in size, complexity, quality and attractiveness across individuals, the highest correlations with genetic quality and phenotypic condition, and the highest correlations with quality and/or quantity of offspring.
Discuss the effects of mutations on faces
Mutations create deviations, so averaged faces are attractive. However, there is also a slight cultural difference between what an average/attractive face is.
Primates pay lots of attention to each others faces, they are very sensitive to the colour, so males tend to have brightly coloured faces which are very ornamented and vary largely across species. However, humans have much less ornamentation and much less variation.
Discuss the relationship between mental charactersitics and fitness signals.
Intelligence, language, mental health, status, wealth and moral values all have a semi-practical and semi signaling property. However, creativity, music, art, humor and happiness are mostly signaling as there is a lack of survival functions for them however they are all sought after in a mate and used to emotionally process attractiveness.
What is the cost signaling theory?
Similar to the self-handicap theory, suggests that signals used for mating often come at a cost. Therefore, if a male can produce these signals, they are fit enough to exert the cost. Cost signaling principles allow a vast range of innovative signals. There are four types of conspicuous signals.
- Waste = size, materials, energy and time to get muscley and large seems like a waste. To keep that size you have to eat large proportions so can afford to spend time and money acquiring those resources and keeping in shape.
- Precision (typicality, symmetry, pattern repitition, fit and finish) = If someone is symmetrical they are able to grow their bodies equally on the left and right side. Or they are more able to build something well.
- Creativity = Spontaneuous novelty 0 why is it needed?
- Reputation = Are they famous?
These signals can serve diverse functions in social primates - intimidate rivals, solicit parental investment (a species of infant primate grows a white circle around face - no benefit!), and attracting mates.
How is the brain a signal of fitness
The brain is vulnerable to mutations. Therefore, if the person is clever, that are likely to lack the harmful mutations. Intelligence isn’t just important for humans, Bowerbirds build bigger bowers if they have biger brains as well as mimicking other species which both predict attractiveness. Songbirds intelligence also predicts song repertoire size which is attractive, some birds evolved very large repertoires through mate choice.
Brain size has also trippledin 2 million years.
Intelligence is also a predictor of humour, which predicts mating success. However, intelligence is not a direct predictor of mating success.
How did we assess a potential mates brain size before language evolved?
Facets: verbal, spatial, abstract, social, emotional, mating.
Heritability: .8 in adults - so we can predict from parents.
Intelligence correlates with body symmetry +.4, brain size +.43, semen quality +.15, fewer neurological abnormalities -.25.
Intelligence predicts school grades, job performance, mental & physical health, longevity, income, wealth, consumer rationality & preferences.
Discuss conspicuous consumption as sexual signaling
Mating primes: men are more motivated to get luxury goods, they volunteer more money & time for charity. They identify luxury goods more quickly and seek more product diversity. They are more risk-taking financially.
Men give higher tips to ovulating lap-dancers.
Short-term mating effort predicts conspicuous consumption & materalism.
Scarcity of women = men spend more and accumulate more consumer debt.
