Wayne 3.3

Front 1

Differentiate between and give examples of qualitative vs. quantitative plant defences, and constitutive vs. facultative (inducible) plant defences.

Back 1

Qualitative Defence: Smaller amounts of specific chemicals to repel herbivores or to attract defender organisms, or spines/thorns. (Poincetta)

Quantitative Defence: Massive layers of tough material to protect valuable parts of the plant - often an option for larger plants. (Coconut tree bark)

Constitutive Defence: Present no matter what.

Facultative Defence: Inducible/triggered

Front 2

Distinguish phenotypic from genetic expression of induced defence traits.

Back 2

Facultative defences can be triggered in the short term or long term. For example, two different areas, deer hang out in one area but not the other. The area with the deers have a plant x with more thorns than in the other area.

Phenotypic Expression - Observable characteristic of the organism. Whereas, an organism can have a genetically determined ability to do something and not make it observable.

Genetic Expression: Distinguishes between constitutive and facultative defences. Genetically determined and genetically determined ability respectively.

Front 3

Explain why generalist, rather than specialist, herbivores are deterred by induced defences.

Back 3

Plants are selected to resist herbivory, and may secrete costly toxins to do it.

Herbivores are selected to acquire adequate energy and nutrients from plants.

Biochemical detoxification is expensive for herbivores and therefore there are less common.

Front 4

Define plant apparency, and explain how changes in apparency may influence plant fitness as environmental circumstances vary.

Back 4

Plant apparency: a plant will invest heavily in broadly effective defenses when the plant is easily found by herbivores

Under different environmental circumstances, it would be beneficial for plants to stop it's defences since it's energetically expensive.

Plants will use constitutive and facultative defences under different conditions:

-Seasonality (tropics will have constant attack)
-r versus k species
-food quality? high quality prey would always be under attack.

Front 5

Relate the concept of plant edibility to the probable importance of defences, and demonstrate your knowledge by designing a simple experiment to test the relationship

Back 5

•! increased nutrients will favour the growth of herbivore- resistant plants over edible ones

•! removal of carnivores from the community will favour resistant plants over edible ones (because herbivores will become more abundant)

•! changes in plant productivity and herbivore biomass will be positively correlated

•! changes in herbivore and carnivore biomass will be negatively correlated

Front 6

Differentiate the various forms of plant defence cost, and explain the difficulties in evaluating the link between them and plant fitness outcomes.

Back 6

ALLOCATION – energy and/or nutrients held by a plant are finite, so whatever is
spent at a given moment on defence cannot be spent on growth, storage, or breeding

OPPORTUNITY – unless young individuals spend on defence, they may never become successful adults (but as adults, they may appear weak and undefended because they had to spend on defence when smaller to survive at all)

ECOLOGICAL – defence against one herbivore type may have no effect (or even a deleterious effect!) against other herbivores, and/or make the plant more susceptible to abiotic stresses; defences might deter pollinators or other mutualists