Lec 12- mating Flashcards
what are the 2 kinds of repro in organisms?
asexual
sexual
asexual repro (4)
binary fission
fragmentation
parthenogenesis
runners
- prokaryotes and eukaryotes (plants and animals)
sexual
combo of gametes
- eukaryotes
why is mate choice important?
sexual selection caused by: mate choice by one sex and/or competition for mates among individuals of same sex causes selection of certain traits
- non-random mating
- sexual display
how to make sense of social interaction related to sexual repro?
- identify sex types
- describe mating sys or social sexual structure of a pop
sex types (3)
male
female
hermaphrodites
single sex
individuals have one repro function
- M and F
M = smaller gametes
F = larger gametes
hermaphrodites
individuals have more than one repro fxn
instantaneous hermaphrodites
can perform M or F functions at the same time
- born w ability
sequential hermaphrodites
can change sex over time
- changes over lifetime
protandrous hermaphrodites
M can change to F if previous breeding F is removed
- clownfish
protogynous hermaphrodites
largest F can change to M if previous breeding M is removed
- Indo-Pacific cleaner wrasse
what kind of sex type are plants?
75% are hermaphroditic
- M and F repro parts
- flowers M and F = “perfect flowers”
- multiple M but 1 female
monogamy
one M and one F in exclusive relationship at least for period of time
- during mating season or while caring for the young
- Emperor penguins
genetic monogamy
parents raise their genetic offspring (full fidelity)
social monogamy
parents raise offspring but fidelity might not be fully present
- 90% passerine species: M raises eggs that might not be his genetic offspring
why did monogamy evolve?
- anisogamy: F more selective since gametes are larger and energetically more costly
- partners are rare or have wide territories
- parental care: higher fitness of offspring
promiscuity
several sexual partners
polygyny
1 male with multiple females
- elephant seals
polyandry
1 female, multiple males
- marmosets
polygynandry
multiple males and females
- chimps
Indian peafowl
M spread out their feathers
- fitness advantage
- visible to predators
secondary sexual characteristics
characteristics M and F not directly involved in repro
- morphological
- behaviors
- sexual selection
sexually dimorphic species
species that display diff secondary sexual characteristics b/w sexes
- moose
- mandrill
- indian peafowl
- human
sexual selection
differences in reproductive rates among individuals as a result of differences in mating success
- intra vs intersexual
intersexual selection
- selection for traits that increases the chances to be chosen by opp sex
- pronounced colors in tail feathers in Indian peafowl
- singing as an acoustic ornament in european robin
intrasexual selection
- selection for traits that confer advantage during competition among same sex for access to mate
- antler size in red deer (M)
- pronounced horns in dung beetles (F)
mate choice and sexual selection
experiments used to understand whether a secondary sexual characteristic evolved through intra- and intersexual selection
Andersson
- length of tail feathers
- longer = higher mating success
- did not play a role in defending territory
Tail feather length evolved through intersexual rather than intrasexual selection
limits of evolution of armors and attractive displays
increased mortality during fights
high allocation of resources at expense of other life function
increased predation risk
habitat compatibility
guppies
tradeoff b/w predation pressure and one hand sexual selection driven by female mating choice on other
- female guppies less colorful than male
- mate with more brightly colored males
high predation treatment- guppies
strong predator
low predation treatment-guppies
weak predator
no predation treatment-guppies
control without predator
Endler experiment on guppies
spots per male body are under intersexual and natural selection (predation pressure)
- 14 months
- reproduce and form several new gen
- low predation and no predation tanks had more spots per male than high predation tank
- from high predation setting were transplanted into low predation setting
- several gen, low predation setting = increase in number of spots on male body
wild radish flowers
both male and female parts
no self-pollination (insects help)
Marshall’s experiment
non-random mating
- pistils of diff individuals were cross-pollinated with six diff pollen donors
- one donor showed increased number of sired seeds
- number of seeds in top half of fruit
what drives non-random mating in plants?
- competition b/w pollen from diff donor in responsible for non-random mating
- interference competition
- interaction b/w pollen inhibits pollen germination (intra-)
sexual conflict
asymmetry b/w sexes in potentially evolutionary benefits and costs of any particular mating event
- expensive F, inexpensive M
- decreased foraging efficiency
- increased predation risk in F while carrying M or offspring
sexual arms race
conflicting benefits/costs of mating has led to coevolution of armaments
- coevolution
coevolution
reciprocal evolutionary interaction b/w 2+ evolving groups (2 species or M vs F)
- water striders: clasping structures in M and anti-clasping structures in F co-evolved in response to sexual conflict)
