Evolution & Natural selection Flashcards
Define natural selection
It implies that in the environment that you are inhabiting the genes that are required to survive and thrive in said environment are naturally selected to be passed on the next generation, so they survive and pass it down further along the line. The main is survival and reproduction so that your species doesn’t go extinct
Define Survival of the fittest
characteristics that aid survival over other characteristics
no aid = die out/no reproducing
strongest genes passed onto the next generation
Define heritable traits
*definition is obvious but there is another factor to take into consideration
Many characteristics have a genetic tendency combined with experiences in the environment. e.g. someone may have a genetic height from their parents- both parents are tall therefore the child has inherited ‘tall genes’. However, their final height/ size can be affected by their environment- e.g. nutrition might affect growth.
Define sexual selection
Can be related to natural selection as the sex of a species have certain characteristics that they desire to pass down to their children for example in the modern day its either intelligence, athletic, beauty and each characteristic can be more prioritised that other depending on the era and environment
Define survival trait
These are anything behaviours or physical characteristics that help an animal survive and reproduce. This can include things like, speed, strength, intelligence, or aggression. These will be traits that will be more desirable to attracting a suitable mate.
Define adaptation and mutation
Adaptation is just a branch to mutation as when it effects the phenotype of the offspring and results in positive effects on the fitness or any characteristics that is required for the environment then it’s an adaptation however if the opposite effects occur and comes out with deleterious effects then referred to as a genetic disorder
Give an example of evolution
enguins traded flight for flippers to swim
Emus and ostriches also traded flight for larger bodies and feet to run stupidly fast on land
Horses in the ice age was no bigger than your average dog hence was prey for most but evolved to not only be bigger but had longer legs to be able to run away from danger more effectively
strength
Buss (1989) conducted a cross-cultural study to show that men and women in many different cultures follow the patterns of behaviour predicted by evolutionary theory for the factors most valued in a mate. Females valued good financial prospects in a potential mate as more important than did males. In 36 out of 37 cultures, males valued physical attractiveness as more important than did females and also found that females in all cultures preferred males who were older, whilst males preferred females who were younger (therefore with greater reproductive potential).
However, Buss found significant cultural differences on some measures; sex differences in mate preference varied between Western and non-Western cultures. Since the evolutionary approach largely discounts cultural differences, this demonstrates a real limitation in the approach.
Davis (1990) considered the content of personal ads in newspapers. Women looking for a mate emphasised their physical beauty and indicated they were looking for a high-status, wealthy man. By contrast, men emphasised their wealth of other resources and made it clear they were seeking a physically attractive, younger woman.
Clark & Hatfield (1989) supported the prediction that females should be more selective than males in their choice of sexual partner. Attractive male and female students approached students of the opposite sex and said ‘Hi, I’ve been noticing you around town lately and I find you very attractive. Would you have sex with me?’ This offer was much more eagerly accepted than male students than females. None of the females accepted the invitation whereas 75% of the males did. However, we don’t know that the responses given would have been the actual behaviour they followed through with!
weaknesses
The evolutionary theory as an innate response has been criticised by psychologists for being deterministic. The theory fails to consider the role of free will of individuals by assuming that behaviours, (such as mate selection), are innate and thus we have no choice in how we behave. This is unlikely to be the case as humans have choices over our behaviours.
Evolutionary theory is also reductionist; it suggests that our behaviours (such as mate selection) to be a result of dispositional factors, ignoring the role of situational factors or the role of the environment. It is likely that we may be attracted to individuals that we are exposed to or have increased contact with. (See next evaluative comment)
Alternative explanations: The mere exposure effect: liking tends to increase with additional contact; therefore, we tend to like people to whom we have been frequently exposed. Saergert (1973) asked female participants to rate the taste of various drinks. During the experiment, they were brought into contact with other women either once, twice, five times or ten times. When asked, participants preferred women they had been exposed to more often, suggesting that exposure to others can on its own lead to positive feeling
an explanation is the evolution of humans
Aggression is an emotion that led to survival in certain environments. The most important survival trait is therefore the ability to switch aggression on and off.
This ability to ignore our instincts and choose whether or not to act aggressively is what enables humans to live together in complex groupings - another survival trait.
an explanation is that its a innate response
you should already be able to explain this using natural selection and the how it involves traits
