Greg Detre
@12 on Wednesday, 24 January, 2001
Psychology LT-A
http://users.ox.ac.uk/~grofen/lectpres (lectpres00)
funny: Darwin�s notes on marriage
Darwin and his addition to Natural selection
difficulties with NS
definition + idea
humans
Modern study of sex selection
types of study
focus on advantages to mate choice
peacock�s tails (�train�)
blackbird song
anters in deer
sexual dimorphism
mating desplay of Great Ccrested Grebe
sexual selection refers to: �the advantage which certain individs have over other individs of the same sex and species in exclusive relation to reproduction� � 1871, Darwin �Descent of man�, pg 256
�being more noticed by, more attractive to, or more persuasive towards the opposite sex, and so gaining a mating advantage� - usually females
�out-competing other members of the same sex in contest whose outcome determines mating success� - usually males
we would now go out into the field with a team, and mark individuals on the basis of lots of different criteria and observe their success
Darwin didn�t have those resources, so he used:
age: juvenile vs adult
sex: male vs female
�disproportionate gains�
|
utilitarian, functional |
showy, elaborate |
|
solves a problem |
impresses an audience |
|
sensible |
whimsical |
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economical |
wasteful |
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fixed |
changeable |
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constructive |
destructive |
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dull |
exciting |
racial differences
skin colour
hair colour and texture
(he thought these differences are quite superficial, and that sexual selection is a better explanation for racial differences because of the short time involved)
gender differences
physical
psychological
analogy to fasion in clothes and personal styles
(beards and facial hair in primates)
no longer trying to defend biology against the creationists
Field empiricial
e.g. Moller on barn wallows
Experimental
e.g. Gerhardt on tree fogs
Comparative method
e.g. Eberhard on reproductive anatomy
Concepts/mathematical modelling
e.g. Lande on runaway processes
fireflies
bird coloration
anatomy of reproductive organs
sperm competition
pollen competition
disease resistance
include polygamy, polyandry, leks and ruts
discuss Alek L???
focusses mainly on preferences
treats preferences as adaptive
non-adaptively: because of sensory bias, species recognition
adaptively directly: for reasons of fertilisation ability, fecundity, nutrition, parental ability, territory quality, avoiding venereal disease, social status of offspring
adaptively through good genes: because of inherited attractiveness of sons, or more general �quality�
Darwin invented sexual selection to accommodate certain kinds of facts within his scheme, and partly as defence against non-biological theories
it firmly established female choice
now certain of sexual selection, but want to know more about why females choose
Fisher�s runaway modle
Lande�s model
Measuring Sexual Selection: Lande/Wade/Arnold
Hamilton/Zuk
Handicaps and signalling
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Darwin (1871) � The Descent of Man
Extracts in M Ridley (1987) � The Essential Darwin
M Andersson (1994)
is sexual selection faster