Life Histories

Question 1

What are the record of events related to life history and complex life cycles?

Answer 1

Life Hx: Growth, reproduction, timing of reproduction, investment in offspring, dispersal ability/tendency, and mortality

Complex life cycles- have 2 distinct phases in morphology, habitat, etc. Ex: alternation of generations

Question 2

What is a morph?

Answer 2

An individual in a population that looks or behaves different than other individuals

Question 3

What is the principle of allocation?

Answer 3

If organisms use energy for one function such as growth, the amount of energy available for other functions is reduced.

Question 4

Iteroparity vs. semelparity

Answer 4

Iteroparity – multiple chances for successful reproduction (repeated breeding)

Semelperity – only reproduce once – a lot of investment goes into making offspring, usually produce a lot of offspring.

ex: octopus, salmon, annual plants

Question 5

r and K life history strategies

Answer 5

r-selection – resources are not limiting. Density independent. Low competition, make many small offspring, lots of reproductive effort.

Ex: rabbits, bacteria

k-selection – resources are limiting. Density dependent. High competition, fewer larger offspring, modest reproduction effort

Ex: humans, large mammals

Question 6

alternation of generations

Answer 6

The alternation of a sexual phase and an asexual phase in the life cycle of an organism.

The two phases, or generations, are often morphologically distinct

Question 7

stress

Answer 7

any abiotic factor that limits fitness

Question 8

disturbance

Answer 8

any process that destroys plant biomass (ex: wildfire)

Question 9

what are competitive plants and where are they found(stress/disturbance)?

Answer 9

plants that have a superior ability to get light, minerals, water, and space will have a selective advantage

low stress/low disturbance

Question 10

what are ruderal plants and where are they found(stress/disturbance)

Answer 10

have a short life span, rapid growth rates, and a heavy investment in seed production

low stress/high disturbance

Question 11

what are stress tolerant plants and where are they found(stress/disturbance)

Answer 11

may have slow growth rates, slow rates of water and nutrient use, low palatability to herbivores, and the ability to respond to temporarily unfavorable environments

high stress/low disturbance

Question 12

sequential hermaphroditism

Answer 12

changes in sex during the course of the life cycle