40 Questions
What determines the growth patterns of an individual, resulting in either no further growth or continued growth after reaching sexual maturity?
Type of growth, either determinate or indeterminate
What is the term for the gradual decrease in fitness with age?
Senescence
Which of the following is an example of phenotypic plasticity?
Two Daphnia clones with the same genotype but different environmental conditions
What is the term for the number of offspring per capita in a given time interval?
Fecundity
What type of growth pattern is characteristic of many species of plants, invertebrates, fishes, reptiles, and amphibians?
Indeterminate growth
What is the primary factor influencing the survival rate of an individual?
Environmental conditions
What is the term for the number of reproductive episodes in an individual's lifetime?
Parity
What is the term for the life span of an organism?
Longevity
What is the term for organisms that have a single reproductive cycle before death?
Semelparous
What is the distribution of survival rates in a population?
Binomial distribution
In which organisms do multiple reproductive cycles occur?
Iteroparous
What is the primary reason for trade-offs in resource allocation?
Resources are limited
What is the main difference between semelparous and iteroparous organisms?
Iteroparous have multiple reproductive cycles, while semelparous have one
What is the outcome of adding one egg to the European magpie's brood?
The success rate decreases to 25%
What is associated with a short lifespan in birds?
Early start in reproduction
What is the main characteristic of stress tolerators in plants?
Slow growth, low fecundity
What is the primary difference between fast and slow life histories?
All of the above
What is the main factor affecting the life history of plants, according to J. Philip Grime?
Stress, competition, and frequency of disturbances
What is the main characteristic of ruderal plants?
Fast growth, high fecundity
What is the result of removing eggs from a European magpie's brood?
The success rate remains at 50%
What is the primary factor influencing the expression of life-history traits?
Environmental conditions
What is the result of phenotypic plasticity in response to predator chemical cues?
Different form and size
What determines the timing of metamorphosis in organisms?
Resource availability
What is the characteristic of indeterminate growth in organisms?
Continued growth after initiating reproduction
What is the relationship between survival rate and longevity?
Survival rate is directly proportional to longevity
What is the primary factor influencing the reproductive strategy of an organism?
Resource availability
What is the characteristic of semelparous organisms?
Single reproductive cycle before death
What is the result of phenotypic plasticity in response to environmental conditions?
Different forms and sizes
What is the primary factor influencing the life-history traits of an organism?
Environmental conditions
What is the characteristic of determinate growth in organisms?
Cessation of growth after reaching sexual maturity
What is the primary reason why organisms cannot live longer, reproduce often, and grow faster?
Resources are limited, requiring trade-offs
What is the trade-off between offspring number and parental care?
More offspring means less per capita care
What is the main characteristic of a slow life history?
Late sexual maturity, long life span, and low fecundity
What is the result of investing more time in feeding offspring?
Lower parental survival
What is the main difference between fast and slow life histories?
Reproductive onset, lifespan, and fecundity
What is the primary factor affecting the life history of plants, according to J. Philip Grime?
Stress, competition, and frequency of disturbances
What is the main characteristic of ruderal plants?
They grow fast and devote a high proportion of their energy to seed production
What is the trade-off between longevity and reproductive onset?
Early start in reproduction is associated with short lifespan
What is the result of adding one egg to the European magpie's brood, in terms of success rate?
The success rate decreases to around 25%
Why do organisms have multiple reproductive cycles?
Because they have evolved to do so
Study Notes
Life History Traits
- Life history traits include growth and development, survival, and reproduction, which can be influenced by environmental conditions and have both heritable and phenotypically plastic components.
Growth and Development
- Phenotypic plasticity: same genotype, different phenotypes in response to environmental cues (e.g., Daphnia clones responding to predator chemical cues)
- Resource availability affects growth and development (e.g., lower body mass in frogs with limited food)
Survival
- Survival rate: proportion of individuals alive at a given time
- Longevity: life span of an organism
- Senescence: gradual decrease in fitness with age
Reproduction
- Fecundity: number of offspring per capita in a given time interval
- Parity: number of reproductive episodes
- Semelparous organisms: single reproductive cycle before death
- Iteroparous organisms: multiple reproductive cycles
- Seasonal breeding: mating occurs during a specific time of year
- Age of first breeding and menopause: significant reproductive milestones
Trade-Offs
- Principle of allocation: energy and nutrients cannot be used for multiple purposes simultaneously
- Examples of trade-offs:
- Offspring size vs number
- Number of offspring vs parental care
- Parental care vs parent survival
- Longevity vs reproductive onset
Examples of Trade-Offs
- Offspring size vs number: big seeds in goldenrod plants contain more energy, but fewer seeds are produced
- Offspring number vs parental care: more offspring means less per capita care, leading to lower survival rates (e.g., European magpies)
- Parental care vs parental survival: investing more time in parental care increases mortality for parents
- Longevity vs reproductive onset: early start in reproduction is associated with shorter lifespan (e.g., birds vs fish)
Groupings from Life History
- Fast vs slow species
- Functional groups in plants (stress tolerators, competitors, and ruderals) based on stress, competition, and frequency of disturbances (Grime's proposal)
Life History Speed Continuum
- Slow life history: late sexual maturity, long life span, low fecundity, high parental investment
- Fast life history: early sexual maturity, short life span, high fecundity, little parental investment
Life History Traits
- Life history traits include growth and development, survival, and reproduction, which can be influenced by environmental conditions and have both heritable and phenotypically plastic components.
Growth and Development
- Phenotypic plasticity: same genotype, different phenotypes in response to environmental cues (e.g., Daphnia clones responding to predator chemical cues)
- Resource availability affects growth and development (e.g., lower body mass in frogs with limited food)
Survival
- Survival rate: proportion of individuals alive at a given time
- Longevity: life span of an organism
- Senescence: gradual decrease in fitness with age
Reproduction
- Fecundity: number of offspring per capita in a given time interval
- Parity: number of reproductive episodes
- Semelparous organisms: single reproductive cycle before death
- Iteroparous organisms: multiple reproductive cycles
- Seasonal breeding: mating occurs during a specific time of year
- Age of first breeding and menopause: significant reproductive milestones
Trade-Offs
- Principle of allocation: energy and nutrients cannot be used for multiple purposes simultaneously
- Examples of trade-offs:
- Offspring size vs number
- Number of offspring vs parental care
- Parental care vs parent survival
- Longevity vs reproductive onset
Examples of Trade-Offs
- Offspring size vs number: big seeds in goldenrod plants contain more energy, but fewer seeds are produced
- Offspring number vs parental care: more offspring means less per capita care, leading to lower survival rates (e.g., European magpies)
- Parental care vs parental survival: investing more time in parental care increases mortality for parents
- Longevity vs reproductive onset: early start in reproduction is associated with shorter lifespan (e.g., birds vs fish)
Groupings from Life History
- Fast vs slow species
- Functional groups in plants (stress tolerators, competitors, and ruderals) based on stress, competition, and frequency of disturbances (Grime's proposal)
Life History Speed Continuum
- Slow life history: late sexual maturity, long life span, low fecundity, high parental investment
- Fast life history: early sexual maturity, short life span, high fecundity, little parental investment
Learn about life history traits, including growth, development, survival, and reproduction, and how they are influenced by environmental conditions, genetics, and phenotypic plasticity. Understand how traits can be affected by conspecific and interspecific effects.
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