BIOL 2390 - Topic 7 (part 3)

Reproductive timing

Refers to the number of times an organism can reproduce over its lifetime

Two types of reproductive timing

1.) Semelparity

2.) Iteroparity

Semelparity

When an organism reproduces only once in its lifetime, usually after a long-term energy investment in growth and storage

Drawback of semelparity

They often reproduce at the expense of their future survival, such that they usually die after reproducing

Iteroperaity

Organisms that reproduce multiple times over a lifetime

Advantage vs. disadvantages of reproducing late

1.) You are more established and have most likely gathered enough resources to support the offspring

2.) But you might not be able to make it to be able to reproduce (i.e. may get picked off by a predator first)

Advantage vs. disadvantage of reproducing

1.) Have a higher chance of actually reproducing before you get picked off by a predator

2.) But you may not have enough resources to support your offspring

Reproductive effort

1.) Refers to how much effort you put into reproduction and caring for offspring

2.) It varies widely among organisms

Balancing reproductive effort

You have to decide how much energy will go towards reproduction and how much will go towards survival and growth, such as tissue production, acquisition of food/territory, and predator escape.

Reproductive effort in plants

1.) Perennials: 15-20%

2.) Annuals: 25-30%

Why do perennials put less effort into reproduction

Perennials grow every year, therefore they have to invest some of the energy for themselves, to ensure they are able to survive throughout the year

Why do annuals pure more effort into reproduction

They only live for a single year, therefore they are able to put more energy into reproduction, since they don’t need it for themselves

Why do crops have a much higher reproductive effort

Because we specifically drive them to have more reproductive effort

Reproductive effort in animals

1.) Common lizard: 7-9%

2.) Salamanders: up to 48%

Reproductive effort in homeotherms

They usually do not allocate as much as energy into reproduction, since they already burn so much energy into maintaining their body temp