Dancing with the Stars Sexual selection Intrasexual selection
- Slides: 42
Dancing with the Stars!
Sexual selection Intrasexual selection: most common is male-male competition Intersexual competition: most common is female choice
What does the fancy stuff say about the male?
• “Are there any cases where sexual selection acts more strongly on females than males? ”
GOAL Why does sexual selection act mostly on males? Predict when would it act on females Investigate secondary hypotheses since Darwinian sexual selection
Bachelor/ette A Bachelor/ette B
‘Averaged’ faces. ‘Averaged’ faces made symmetrical.
Natural faces Artificially symmetrical faces
Renee Firman and Leigh Simmons University of W. Australia “a relationship between body symmetry and semen quality and quantity in men”
“Across diverse taxa, increased asymmetry is associated with: • Increased morbidity • Mortality • Poor fecundity” Developmental Stability and Evolution Moller and Swaddle
Part of the Jamaican Symmetry study • “In humans fluctuating asymmetry has been shown to be related to age, body weight, metabolic rate, running speed, intellectual performance, predisposition to breast cancer, and other harmful conditions” Assumption = symmetry implies underlying good genes
Bateman’s principle • In species where mothers invest more in the offspring than do fathers, females are expected to be more selective in mate choice
• And so males are expected to invest more in courtship display
Option 1 • Be fabulous
Option 2 • Build or do something fabulous
Option 3 • Make more sperm A highly polygamous species of woodmouse
Females mate with multiple males. ? ? Females mate with a single male.
Option 4 • Make better sperm Drosophila bifurca One D. bifurca sperm (6 cm long, about 20 x that of the fly)
The idea for today • If you look fabulous, or are doing something fabulous, a female needs to correlate the fabulousness with underlying good genes
Darwin: • “The females are most excited by, or prefer pairing with, the more ornamented males, or those which are the best songsters, or play the best antics; but it is obviously probable that they would at the same time prefer the more vigorous and lively males, and this has in some cases been confirmed by actual observation. ” Origin of the Species
If so, then… • Courtship rituals should reveal genetic or phenotypic quality (and therefore, symmetry)
In Jamaica… • Dance is experienced as an important courtship ritual
Nature 438: 1148 -1150 (Dec. 22 2005)
Predictions the authors made: 1. Symmetrical people will be perceived as better dancers. 2. Symmetry’s effect will be stronger in males. 3. Females will be better at seeing the effect of symmetry on dancing ability.
Thus, the degree of symmetry should more strongly correlate with male dancing and females should discriminate better
Dancing was recorded using reflectors on the dancers’ bodies.
OK, ladies! • Which dancer is more symmetrical? Bachelor number one or… Bachelor number two
Results Symmetrical people are perceived as being better dancers
Females are better discriminators
A jarcana, a species where females compete for males
Zahavi’s handicap principle Female thinking “Wow- for you to survive, with that big of a target on your back, you must be pretty robust”
Fisher’s Runaway Selection Hypothesis The trait being selected for is driven to such an extreme that fitness is reduced.
Fisher’s Sexy Son hypothesis Female choice: Small antlers = son with higher chance of survival Big antlers = son with higher chance of having sex
Zahavi’s honest advertising (assume same scenario as previous slide- this Is a lead-off of the handicap principle) In version A, the male has a long tail that he grew and with which he survived the slings and arrows of multiple negative selective forces. In version B the male does not have an excessively long tail, but whenever he senses that a female may be looking, he hangs a long branch of a certain tree from his butt so he looks like he has a long tail. Females that can’t choose have lower fitness. Females are selected to detect honesty.
Linden Fragile Male hypothesis Here, females drive males into a state of fragility by selecting for traits that reduce survivability and longevity. This allows the female to get what she needs from the males (a mix of genes) with a greater chance that the male will fall out of the picture sooner than later.
A very fit, asymetrical male!
- Intrasexual vs intersexual
- Intrasexual and intersexual selection
- Secual selection
- Fisher's runaway hypothesis
- Directional selection example
- Bbc grundades
- 7-eleven
- Sand dollar anatomy
- Dancing with stars
- Labisi
- Dancing stars
- Dancing the stars
- The stars there are millions of stars in the sky
- Intrasexual
- Intersexual selection
- Disruptive selevtion
- Evolution means
- Created by combining locomotor and non-locomotor movements.
- Dancing shoes helene schjerfbeck
- Dancing
- A day with nandu
- Dancing me
- Dancing with demons yelena garcia
- Dancing used to be my favorite hobby
- Jazzy musical theater songs
- Dancing the
- Dancing with
- The vertical distance from the floor in dancing
- What is size in elements of dance
- Dancing man cipher
- It is any human movement included in the act of dancing
- Rapper sword
- I like dancing
- Dancing the
- Even though the banana seemed to change color
- Thinking involves mentally grouping similar objects
- I was dancing with my darling
- Pros and cons of dancing
- Chong ho yu
- Clip clop plodding along to bethlehem
- Everyone dancing merrily in the new old-fashioned way
- What does bible say about dancing
- Square dancing terms