Life Histories Flashcards
How does size influence life history traits?
Increase competitive ability, predator success, predation vulnerability, time to grow and prefernce for larger prey
Copes Rule
Says that population lienages increase in body size over evoloutionary time
Types of reproduction?
Semelparity -(Death following first repro)
Iteroparity -(Repeated bursts of repro)
Reproductive Allocation
Is the amount of energy budget put into reproduction
What is RA sum of?
Reproductive output and future reproductive value
What life history trait is favoured by NS?
The one most highly represented based on contemporary output and future reproductive value
What is reproductive value?
Currency of worth of life history traits
How is repro value mathematically describes?
Sum of survivorship, reproductive outpiut and age difference
Reproductive Value
How different age classes contribute to population growth or total lifetime expectancy of reproductive value
Why do LH trade offs arise?
Resources allocated to particular traits
Example of LH trade offs?
Trees maximise repro through growth and seed production, however increase in one decreases other.
When may there be positive correlation in LHTO?
Increased reports, depicted by a Y model, C into one whilst 1-C into other
How can trade offs be revealed experimentally?
Increasing selection pressure on one species, boosting/reducing LH traits by trade offs
Example of geneticb asis of LHTO?
Subjecting species to a viruse that they become resistance to experienced decrease in rate of development, that being subjection to selective pressure
Example of LHTO in soay sheep?
Allele Ho+ of RXFP2 gene gives short horns whilst allele Hop large horns, Hop homozygotes decreased reproduction stress than heterozygotes and Ho+ homozygotes
Quantitative Trait Loci
Is a DNA region associated with a speciifc phenotype of trait
Cost Of Reproduction
This is resource allocation to reproduction that likely decreases survival, thus future reproduction potential
How do number/fitness of offspring relate?
Inversely proportional
Options Set
Describes the range of combinations of two life history traits as organisms is capable of exhibiting
What do options curve represent?
Physiology of organisms, beneath curve traits able to be bettered
Fitness Contours
These join combinations of present reproduction and growth, for which overall fitness is constant.
How does habitat affect CR?
Low CR RRV less affected by current reproduction, fitness determined reproduction, high CR means present reproduction has negative correlation with growth
What regulates reproduction investmenet/timing?
Habtiat effects on organisms,
How do growth stages influence repro allocation?
The older one gets, the larger they grow
Terminal Investment Hypothesis
This says decreased expected future reproduction value increases investment in current reproduction
Evidence of TI Hypothesis?
Terminal infection of birds increase reproductive allocation,
Example of cause and effect seperation?
Increased resource allocation may increase death rate, as opposed the other way around
Options sets of Size/Number of offspring?
Affected by low and high CR habitats, reproductive value of offspring rising with high CR habitats
How is clutch size optimally selected for?
Most individuals and highest survival rates, influenced by resource availabiltiy and allocation by parent to offspring
R Strategists
Shorter lifespans, smaller, produce many young, exponentially grow
K Strategists
Exhibit logistic growth, have longer lifespans, produce fewer young, arel arger
What are expected traits in K strategists?
Lower reproductive allocation, larger/fewer offspring, iteroparity and larger size, increasing survival over reproduction.
Fast-Slow Continuum
This depicts R/K strategists on a scale, depicting fewer traits on the continuum, and doesn’t require habitat/taxonomy integrally
Principal Component Analysis
This is a statistical method taking explanatory variables that may themselves be correlated with one another, and converts them into a smaller set of uncorrelated principle components to which the orgiinal variables contribute
How does PCA work?
PCA1 epxplains greatest proportion in orgiinal trait variation
PCA2 explains the next greatest proportion
Factor Analysis
Can also be used to reduce a large number of variables into fewer numbers of factros
Case Study of F/S continnum…
Invasiveness determined by where they would sit here, slow end increasing likelihood of invasiveness and less likely to be endangered.
Example of phylogenetic/taxonomic constraints of life-history traits?
Order procellariformes clutch size of one ubiquitously
How does size constrain organisms?
Unicellular limited to size due to O2 diffuson, insects rely on trachae, mammals have to exceed certain size for endothermy
Allometry
This is the relationship of organism size and physiology
Phylogenetic distance relationship to LHT?
Increases difference with distance
Example of phlogenetic constratins?
Two distinct taxa coinciding in habitat differ due to phylogenetic constraints
