From Biol301

Contents 1 Life History continued 1.1 Parity 1.1.1 Semelparity 1.1.2 Iteroparity

Life History continued

• Form basis of population growth rate
• Life history traits are sensitive to environment
• Life history traits are determinants of fitness
• It is all about allocation of energy to:

1. Growth
2. Development
3. Maintenance and Repair
4. Reproduction
5. Storage
6. Parental Care

Parity

• Parity = how many times and how often an organism reproduces
• Optimal strategy depends on environment and how it affects the age-specific liklihood of surviving

Semelparity

• Reproducing once then dying
• Must have cue and synchrony of response
• Cue must suggest that if one reproduces now, the offspring will do well.
• Synchrony must occur because the offspring must have other organisms to mate with.
• Advantages:

1. Reproduction occurs in good years.
2. Massive floral display is effective for attracting polinators
3. Seed massing is useful as it can overwelm predators' ability to eat all the offspring; called masting
4. Fecundity is increased because energy is focussed on growth for time leading up to cue.

• Fecundity versus survival: adult to juvenile mortality rate determines fecundity versus survival (i.e. how much energy is devoted to reproduction as opposed to maintenance and repair)

Iteroparity

• Having offspring more than once on some sort of interval
• Example: humans