BIOL150 Study Guide - Final Guide: Assortative Mating, Altricial, Semelparity And Iteroparity
13 Jan 2017
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BIO 150
Life History
-Life history is the lifetime pattern of growth, development and reproduction
-Predicts how natural selection shapes the way organisms invest their resources offspring into
producing offspring to maximize fitness
-Life History traits
-Size at birth
-Growth pattern
-Age and size at maturity
-Number, size and sex of offspring
-Age and size specific reproductive effort
-Age and size specific survival rates
-Life span
-Types of reproduction
-Asexual: offspring are genetic clones of parents
-Types
-Fission - bacteria split in two
-Budding - grows in the side then buds off
-Parthenogenesis - Creating offspring without male fertilization
-Fungi asexual spores - mitosis
-Vegetative reproduction - e.g stolons and and rhizomes (plants)
-Apomixis
-Sexual
-Sexual vs. Asexual
-Asexual
-High fitness under current conditions
-Rapid population growth
-Low genetic variability - less adaptable to changing conditions
-Sexual
-portfolio effect: genetic diversity minimizes the volatility of the population’s response to
changes in environment conditions
-more raw material for natural selection to act on
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-takes time and energy if resources are scarce and seasons short
-Modes of reproduction
-Animals
-Unisexual: one male one female
-Hermaphroditic: individuals posses both male and female organs
-Rapid expansion followed by colonization
-Simultaneously hermaphrodite - individuals posses both male and female organs
-Sequentially hermaphrodite - the removal of male stimulates the largest female to
replace him
-Plants
-Imperfect
-Monoecious
-Dioecious
-Perfect
-Bisexual (monoecious)
-hermaphrodite
-Mating systems: Animal
-Monogamy - single pair bond, co-parenting
-homogenous territories
-Polygamy - heterogeneous territories that are defended by the parent not rearing the child
-Polygyny: 1 male, >1 female, female raise offspring
-Simultaneous
-Harem size related to synchronicity of sexual receptivity
-Polyandry: 1 female, >1 male, male raise offspring
-Typically sequential e.g Sandpipers
-Improved fitness of female: tortoises with mixed paternity clutches
-Eusocial: dominant breeding female, non-fertile siblings raise offspring
-Promiscuity: no pair bond - one parent provides no resources or care
-Sexual Selection
-Intrasexual selection
-within-sex competition for mates
-promotes sex traits like aggressiveness, antlers
-Intersexual selection:
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-between sexes (attractiveness)
-courtship and ornamentation
-results in assortative mating: mate choice by phenotypic traits
-often the females choice
-Reproductive effort - cost to future reproductive success on the parent in the form of reduced
survival, fecundity and/or growth
-Number vs offspring size
-Strategy 1: generate a lot of offspring, invest a little in each, and with low survivorship.
-Altricial: young born helpless
-Increase parental fitness, but decrease the fitness of the young
-Strategy 2: produce few offspring, but invested heavily in each to maximize survivorship
-Precocial: longer gestation, young are born at a more advanced
-Increase the fitness of the young at the cost of the parents
-Current vs. future reproduction
-Strategy 1: Semelparous
-Lots of offspring, few reproductive events
-Strategy 2: Iteroparous
-Few offsprings,, and lots of reproductive events
- Favoured where
-reproductive effort yields decreasing returns or
-mortality increases as the effort increases
-Current reproduction vs. survival
-Red deer that had a baby (milk) have higher overwinter mortality than those that did not
have a baby (yeld)
-Age related
-Declines in kidney fat due to energetic costs of lactation
-Milk hinds are also less likely to conceive the next year
-Current reproduction vs. parental growth
-Natural selection will favour the age of maturity that results in the greatest number of
offspring produced over the lifetime of an individual
-The sum of life history traits is your life history strategy
-r vs. K - mainly in animals
-related to logistic models of population growth
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Document Summary
Life history is the lifetime pattern of growth, development and reproduction. Predicts how natural selection shapes the way organisms invest their resources offspring into producing offspring to maximize tness. Asexual: offspring are genetic clones of parents. Budding - grows in the side then buds off. Parthenogenesis - creating offspring without male fertilization. Vegetative reproduction - e. g stolons and and rhizomes (plants) Low genetic variability - less adaptable to changing conditions. Portfolio effect: genetic diversity minimizes the volatility of the population"s response to changes in environment conditions. More raw material for natural selection to act on. Takes time and energy if resources are scarce and seasons short. Hermaphroditic: individuals posses both male and female organs. Simultaneously hermaphrodite - individuals posses both male and female organs. Sequentially hermaphrodite - the removal of male stimulates the largest female to replace him. Polygamy - heterogeneous territories that are defended by the parent not rearing the child. Polygyny: 1 male, >1 female, female raise offspring.
