lecture 14: life history part 1 Flashcards
Life history is
- Lifetime pattern of growth, development, and reproduction
- strategy for survival and reproduction e.g. fitness
- shared strategy connects indiv within a pop’n
Asexual offspring
-Genetic clones of parents
Not much genetic variation because no secual recombination of DNA
Types of asexual reproduction
- Fission: eg bacteria split into 2
- Budding: eg hydra- freshwater jellyfish
- Parthenogenesis: female’s egg gives rise to offspring with no paternal contribution
- Fungi asexual spores (mitosis)
- Vegetative reproduction (eg stolons and rhizomes - root thingy)
- Apomixis: unfertilkized seeds
portfolio effect
in sexual reproduction, genetic diversity minimizes the volatility of the pop’s response to changes in environment condition
unisexual
separate male and female indiv
hermaphroditic
indiv possess both female and males organs (rapid expansion following colonization)
dioecious
unisexual plants, having male and female organs on SEPARATE plants
bisexual
type of hermaphroditic species plants:
- perfect
- both male organs (stamens) and female organs on the same flower
monoecious
type of hermaphroditic species plants:
- imperfect
- male and female organs on separate flowers by on the same plant
simultaneous hermaphroditic
e. g. earth worms possess both male and female sex organs simultaneously (they reproduce sexually though)
- keep both organs during life time
sequentially hermaphroditic
will change from one sex to the other (and typically cannot revert)
-e.g. parrot fish, the removal of a female stimulates males to become female. less often the removal of a male induces the largest female to replace him.
Monogamy
single pair bond between 2 indiv (e.g. red foxes), homogenous territories
Polygamy
heterogeneous territories defended by the parent not responsible with rearing the offspring
polygyny
1 male and many female mates, females rear offspring
polyandry
1 female and many male mates, male raises offspring
**eusocial: dominant breeding female
promiscuity
no pair bonds - males provide no resources or parenting help
Outcrossing
Reproductive fertilization (eg pollen from one plant fertilizes an egg from another plant)
Autogamy
Self fertilized seed (self fertilization, strongest form of inbreeding)
Apomixis
Unfertilized seed (without meiosis and sexual recombination)
Intrasexual selection
Within-sex competition for mates’ promotes sex traits like aggressiveness, etc
Intersexual selection
- between sexes (attractiveness)
- courtship and ornamentation
- results in assortative mating: mate choice based on phenotypoic traits
- often the female’s choice (not always)
Trade-offs of sexual selection
- Fitness requires reproduction, not just survival
- traits can become advantageous which actually decrease your survival (as long as it increases your attractiveness)
- peacock tails, swordtail fish
Risks and benefits of sexual reproduction
risks: swimming efficiency is lower in swordfish, higher predationpredation for swordfish
Benefits: increased reproductive success
What is Wattled Jacana
- birds with long toes in aquatic habitat
- polyandry: female mates with as many mates as possible, males incubate eggs and raise offspring
- females compete for mates and territory
- reasoln: crocodile predates their eggs, so they want to have as many eggs as possible
what is mate choice based on
- Perceived genetics
- ability to survive, bright colors show Hugh resistance against parasites and disease - Provision of resources
- males that defend territories come with resources, balance mate quality and territory quality
