PL SC 324 Lecture 4: Traits and Trade-offs

Plant Traits

A very broad term, which comprises almost everything that can be quantified or qualified about an individual plant:

Size, size of parts, seeds, number and size, reproduction growth form.

r-Strategists evolve when

adults have higher mortality

K-strategies evolve when

adults survive

r-selection

reproductive strategies, Increase reproductive effort earlier

K-selection

Lower reproductive effort, later in life

Because the population is commonly near carrying capacity, they have evolved to be competitive.

Explain Grimes CSR Theory

3 broad ecological strategies of plants (Competitor, Stress-tolerator, Ruderal)

-Stress tolerators: tolerate environments that other plants cannot

-Ruderal: population disturbed areas like agricultural land, put lots of effort into quickly setting seed.

-Competitor: Dominate the area so no other plant can grow, ex: quack grass

When is competition lowest in plants and highest

Lowest: at low productivity (because plants are adapted to stress conditions). Highest: At high productivity (Plants are adapted to obtain resources quickly

Name some of the CSR habitat associations

Name some of the CSR trait associations

Trade-offs

Evolutionary dilemma whereby genetic change conferring increased fitness in one circumstance inescapably involves sacrifice of fitness in another. A plant cannot optimize all aspects of its life history.

Explain some tradeoffs when it comes to seed traits

Seed size vs Seed number

-Larger seeds are more likely to be eaten, smaller seeds are less likely to survive environmental conditions.

Seed size vs seedling performance

-Larger seeds will be more competitive

Seed size vs Dormancy

-Large seeds tend to germinate sooner

Colonization vs Competitive ability

Palatability vs Competitive ability

Longevity vs Reproductive Output

Growth vs Reproduction

LMA vs Photosynthesis or nutrient efficiency

Do the RGR units activity

(It’s on eclass 😄 )