Life history traits are products of natural selection What are life history traits? What defines an
organisms\' life history? Define and distinguish between semelparity and iteroparity. Explain
what factors may favor the evolution of each life history strategy.
Solution
1.Life history characteristics are the traits that affect the life table of an organism, and can be
imagined as various investments in growth, reproduction, and survivorship.
The trait is the most important for any organism and the change in the trait may create the
difference in the organism’s level of fitness.
Evolutionary forces act on life history traits serves to limit the genetic variability and heritability
of life history strategies.
The list of the traits are size at birth, growth pattern, age and size at maturity time, number, size
and sex ratio of the offspring, reproductive and mortality rate and length of life.
2.Mostly many factors define the life history of organism but especially the unpredictability of
environment.
Unpredictable environment resources, hazards and competitors may fluctuate and select
organism that produce more offspring than earlier and it also leads to the plasticity where the
individual can shift along with the spectrum.
3.Semelparity and iteroparity are the two reproductive strategies in living organisms.
Semelparity is characterized with single reproductive cycle before death and iteroparity is
characterized with multiple reproductive cycles during its life time.
Examples for semelparity are salmon pacific fish, butterflies, mayflies, cicadas, some mollusks,
arachinids.
Examples of iteroparity are mammals ,reptiles, birds etc.
4.Life history traits and the life events combination creates the life history strategies.
Body size, age of maturation, high or low survivorship, and the environment type are some of the
factors that favours the evolution of life history strategies.
The type of behavior taking place at the life event may define the life history strategies.
The life history strategy is the age and stage specific patterns and all the stages of life make up
the organisms life..
Life history traits are products of natural selection What are life .pdf
1. Life history traits are products of natural selection What are life history traits? What defines an
organisms' life history? Define and distinguish between semelparity and iteroparity. Explain
what factors may favor the evolution of each life history strategy.
Solution
1.Life history characteristics are the traits that affect the life table of an organism, and can be
imagined as various investments in growth, reproduction, and survivorship.
The trait is the most important for any organism and the change in the trait may create the
difference in the organism’s level of fitness.
Evolutionary forces act on life history traits serves to limit the genetic variability and heritability
of life history strategies.
The list of the traits are size at birth, growth pattern, age and size at maturity time, number, size
and sex ratio of the offspring, reproductive and mortality rate and length of life.
2.Mostly many factors define the life history of organism but especially the unpredictability of
environment.
Unpredictable environment resources, hazards and competitors may fluctuate and select
organism that produce more offspring than earlier and it also leads to the plasticity where the
individual can shift along with the spectrum.
3.Semelparity and iteroparity are the two reproductive strategies in living organisms.
Semelparity is characterized with single reproductive cycle before death and iteroparity is
characterized with multiple reproductive cycles during its life time.
Examples for semelparity are salmon pacific fish, butterflies, mayflies, cicadas, some mollusks,
arachinids.
Examples of iteroparity are mammals ,reptiles, birds etc.
4.Life history traits and the life events combination creates the life history strategies.
Body size, age of maturation, high or low survivorship, and the environment type are some of the
factors that favours the evolution of life history strategies.
The type of behavior taking place at the life event may define the life history strategies.
The life history strategy is the age and stage specific patterns and all the stages of life make up
the organisms life.
