Evolution and Emotion - Semester 2 Flashcards
What is evolutionary psychology?
The study of human nature in the light of evolutionary thought.
What is the goal of evolutionary psychology?
- To answer why we are the way we are
- What psychological traits can be traced to our evolutionary past, and what to culture?
What is human nature?
- The set of species-specific traits that distinguish humans from other species includes (non-exhaustive list):
- Intelligence
- Language
- Morality
- Sexuality
- War, aggression
- Society
- Fashion
- Religion
- Science and technology
- Learning
- Art and beauty
- Cooperation
- Culture
- Music
What is evidence of evolution?
- Geological stratification of fossils
What is archaeopteryx?
Archaeopteryx - there is a mix of structures between birds and reptile
What do fossils allow us to do?
Fossils allow us to trace how things have changed over time
What is evidence of shared traits (common descent)?
- Common body plan: homology
- Common developmental pathways: embryology
- Shared/similar structures to other species
What are examples of vestigial traits (serve no function)?
- Eyes in a cave dwelling fish
- Pelvis in python
- Ear muscles in humans
- Why change something that is causing no harm even if they no longer have a purpose. (They may have had a purpose in the past but no longer
What are some examples of bad ‘design’ of the human body?
- One of the only species that are at risk of choking
- Most people will experience sore knees as lots of pressure are on our knees – points to us likely have been a species who walked on all fours.
- Not a perfect design but still a functioning design, making the best of what we have
What is the traditional definition of evolution?
- Definition: heritable changes in a population over time
It is simply a change, any change
Note: not changes within a individual = development
What is the modern definition of evolution?
- Modern definition: the change in gene frequencies in a population over time
What changes is the genetic composition
What is the purpose of evolution?
- Modern definition: the change in gene frequencies in a population over time
What changes is the genetic composition
How does evolution occur?
- Organisms seem to be adapted to their environment (e.g. bees and flowers) Why and how are they so well suited?
- William Paley – 18th century
What is natural selection?
- The most powerful explanation of evolution and adaptations in living organisms
- ‘Nothing in biology makes sense except in the light of evolution [Natural selection]’ – Dobzhansky, 1973
Whom does adaptations benefit?
- Biosphere
- Species
- Groups
- Individuals
- Genes
- Overwhelming evidence that it is genes that benefit genes the most
What is inclusive fitness?
- Number of gene copies passed on to the next generation
- Inclusive fitness = direct + indirect fitness (example below)
If you have two children and three nieces
Inclusive fitness = 0.5 x 2 + 0.25 x 3 = 1.75 copies
What is direct fitness?
Direct fitness: through own offspring
Self to offspring = half a copy
What is indirect fitness?
Indirect fitness: through relatives’ offspring
Self to nephew/niece = one-fourth copy
What is adaptation?
- Adaptation (and hence natural selection) favours traits that maximise inclusive fitness…
- Most of the time, inclusive fitness correlates with individual survival but not always.
- For example, eusocial insects, altruism (might return to this in another lecture)
Are all biological traits adaptive?
No
What are evolutionary by-products?
Neutral to natural selection
Male nipple
What is an example of a maladaptive trait but with trade of benefits?
Choking and speech in humans
What are the uses of traits like peacock feathers?
- These traits have no relevance for survival but only enhance inclusive fitness
What are the two kinds of sexual selection?
Inter-sex selection
Intra-sex selection