Life history evolution and reproductive value

Why is duckweed the closest we can get to a darwinian demon in nature? (3)

1. can divide every 24 hours 2. doesn't have to mate/pollination3. doesn't need to build supportive tissue

What are two trade offs that pond weed has to worry about that darwinian demons wouldn't?

reproduction vs survival, number of offspring vs quality of offspring

What does life history theory study?

how traits influence fitness at different stages of an organism's life, from birth to death

What are life history trait examples? (6)

Size at birth

Age at maturity

Number and size of offspring

Growth pattern

Lifespan

What is an example of an animal that produces very small offspring?

kangaroo (Macropus giganteus)

What are two types of growth patterns?

determinate and indeterminate

What is an indeterminate growth pattern?

growth continues with age

Why do aphids have very young age at maturity?

an aphid gives birth to live "pregnant" daughters

Why do agave "century" cactus have a very old age at maturity?

an agave "century" cactus can wait 50 years before it flowers

What is an example of an animal that lays one large egg?

the kiwi bird

What are examples of animals that produce lots of offspring?

clams

How can sex be determined in some species?

by temperature

What is an example of a species with a very long life span?

A 32,000 year old Silene stenophylla (plant)

What is the vertebrate with the shortest life span?

the pygmy goby

What does individual life history strategies determine?

population growth rates

How do you calculate the reproductive success of each age class?

birth rate x the probability of surviving to that age class

How do you calculate the average lifetime reproductive success?

the sum of the reproductive success across each age class

What is reproductive value?

the average contribution to the ancestry of future generation made per individual for each age class

What is reproductive value often compared between?

males and females

In a diploid, sexually reproducing population what is the genetic value/ reproductive value of males and females?

exactly equal

What can reproductive value be used to understand the evolution of?

clutch size - the clutch size that leads to the highest reproductive value is the lack clutch

Why might parents value older offspring more highly?

older offspring have higher RV than newborns so parents should be selected to value them more highly

What is an example of parents valuing older offspring more highly?

in difficult conditions, parent birds may neglect their younger chicks to increase the chance that at least one will survive

What is the average RV for newborn giant clams and what does this mean?

much lower than for humans and so an individual offspring is less valuable to its parents

When does the strength of selection peak?

in early adulthood - deleterious mutations are expressed at this age and more likely to be selected out

What doe the menopause mean for female humans?

women continue to live beyond the point at which RV drops to zero