Adaptation
Biological traits or characteristics that help an individual survive and reproduce in their habitat. Each adaptation performs a specific function.
Natural Selection
Differential survival and reproduction as a result of the heritable differences between organisms. It requires:
1. Individual differences within a population
2. Reproduction between individuals
3. Heritability
Stabilizing Selection
Selection that acts against any sort of departure from the species-typical adaptive design (keeps traits stable over-time)
Darwinian Fitness
The average reproductive success of a genotype relative to alternative genotypes
Sexual Selection
The component of natural selection that acts on traits that influence an organism’s ability to obtain a mate.
Intersexual Selection
The preference of the opposite sex drives selection of a trait. (ex. Peahens prefer peacocks whose tails are more symmetrical)
Intrasexual Selection
Success in combat with opponents of the same sex drives selection of a particular trait
4 Types of Social Behaviours
- Cooperation (helps both parties)
- Selfish (helps themselves, hurts others)
- Altruism (helps others, hurts themselves)
- Spite (hurts both parties)
Altruism
An actor incurs a cost in order to provide a benefit to a recipient
Inclusive fitness
Fitness from both direct and indirect sources; fitness from personal reproduction and reproduction of genetic relatives
Direct fitness
An individual’s personal genetic contribution to the next generation through reproduction.
Indirect fitness
An individual’s genetic contribution to the next generation through the reproduction of close genetic relatives
Hamilton’s Rule
An equation, which predicts when altruistic behaviour will be performed, defined by the inequality rB>C
r
degree of relatedness that represents the probability of identical genes
(ex. 50% parents, 50% siblings, 25% half-sibling, 25% aunt/uncle, 12.5% first cousin)
B
reproductive benefit to the recipient
C
reproductive cost to the actor
Phenotypic matching
An evaluation of the relatedness between individuals based on an assessment of phenotypic similarity; used for kin recognition
Kin recognition
The ability to recognize the relatedness of other members of a species (through aspects such as location of behavioural activity) and perform altruistic acts accordingly.
Direct reciprocity
Situations where individuals help each other and both benefit.
Indirect reciprocity
Occurs when individuals help others, who have helped other.
Phylogeny
A pattern of evolutionary development and divergence of distinct lineage from common ancestors
Romantic jealousy
Feelings of anger and desire to guard a male from emotionally investing in a new relationship.
Sexual jealousy
Feelings of anger and desire to guard a mate (or prospective mate) from engaging in sexual activity with another person
Fluctuating asymmetry
A measure of bilateral traits that are symmetrical over the population as a whole, but not necessarily for an individual (Higher symmetry is considered more desirable)
Ex. An optimal body has two legs of the same length; this can differ amongst individuals due to physical injuries and diseases
