Term
| when caught between "plants and predators" what must herbivores deal with? |
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Definition
| herbivores must deal with the chemical and morphological defenses of plants while simultaneously defending themselves from their own predators |
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Term
| what does the study of plants and their herbivores lead to? |
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Definition
| it leads to new understandings of interactions involving more than two trophic levels |
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Term
| What are the assumptions from Ehrlich-Raven theory? |
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Definition
- herbivore activity is harmful to plants.
- plants are able to evolve defenses that are effective in deterring feedinb by herbivores:
- Although Ehrlich-Raven theory stresses herbivores, these plant chemical defenses could just as easily have been evolved to defend plants aganist attacks by fungi, bacteria and other microorganisms.
3.) Herbivore feeding activities, growth, reproduction and evolution have been guided by the ability of plants to defend themselves both physically and chemically.
4.) although there exist herbivores that feed on plants of many species, genera or families with seemingly little regard for the identity of the plants, these "generalists" are actually much more selective than they appear. |
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Term
| If the majority of herbivore species are not generalists, then what are they? |
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Definition
| specialists, feeding on just one plant species, one plant genus, or perhaps one plant family (for example the Cruciferae or mustard family). |
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Term
| how are allelochemicals characterized? |
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Definition
| Allelochemicals are characterized as having a negative impact on herbivores, disease organisms or other plants. |
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Term
| The three main classes of secondary compounds are carbon based compounds such as: |
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Definition
- terpenoids
- phenolics
- nitrogen-based compounds, such as alkaloids
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Term
| from where are terpenoids or isoprenoids formed? |
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Definition
| formed from acetyl coenzyme A and are built on five-caron units into larger molecules |
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Term
| What do phenolics include? |
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Definition
| include plant pigments such as anthocyanins but also include the bitter-tasting tannins and a major component of wood lignin |
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Term
| What are the major groups of nitrogen based compounds? |
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Definition
| alkaloids, the glucosinolates of the mustard family (Cruciferae) and nonprotein of amino acids. |
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Term
| What are two groups which glycosides fall into? |
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Definition
-cyanogenic glycosides (which contain nitrogen)
-cardiac glycosides (those found in milkweeds) do not |
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Term
| In terms of "money" how is production of alkaloids? |
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Definition
| The production of alkaloids is metabolically expensive |
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Term
| What is required to synthesize a gram of alkaloid? |
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Definition
| it is requires 5g of photosynthetic carbon dioxide, while a comparable figure would be 2.6g for a phenolic |
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Term
| what is the main difference between Theobromine and Caffeine? |
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Definition
| The main difference is that the NH group in theobromine is an N-CH3 group in caffeine. |
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Term
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Definition
| theobromine is a bitter alkaloid of the cacao plant, found in chocolate, as well as in a number of other foods, including the leaves of the sea plant, and the kola or cola nut. |
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Term
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Definition
| caffeine is found in coffee plants, tea and the kola nut. Kola nuts are native to Africa, but are related to cacao plants, which are native to the American tropics. |
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Term
| what can caffeine and theobromine cause? |
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Definition
| they both can cause sleeplessness, tremors, restlessness, anxiety, as well as contribute to increased production of urine |
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Term
| In humans, what can caffeine act as? |
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Definition
| it can act as a natural nervous system (CNS) stimulant, temporarily warding off drowsiness and restoring alertness |
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Term
| what kind of property does caffeine have? |
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Definition
| caffeine has diuretic properties |
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Term
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Definition
| it paralyzes and kills certain insects feeding upon the plant. High caffeine levels have also been found in the soil around coffee bean seedlings. |
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Term
| how can caffeine function as? |
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Definition
| It functions both as a natural pesticide as an inhibitor of seed germination. |
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Term
| What are phenolic compounds essentially? |
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Definition
| Phenolic compounds are essentially ubiquitous in the plant kingdome; they are found in ferns and gymnosperms, as well as in angiosperms |
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Term
| how are phenolics defined? |
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Definition
| it is defined as compounds with aromatic structures with one or more hydroxyl groups attached |
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Term
| what is the total number of known phenolic compounds (to be estimated)? |
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Definition
| it is estimated to be 8,000 |
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Term
| what are phenolic compounds? |
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Definition
| phenolic compounds are broadly toxic to most forms of life. Due to their ability to form cross-links with proteins and other polymers, phenols and tannins are capable of inhibiting enzymes, are also markedly astringent. |
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Term
| What is the main effect from phenolic compounds? |
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Definition
| The main effect of these compounds is to inactivate the digestive enzymes of herbivores, especially insects |
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Term
| To whom does phenolic compounds make it difficult to extract amino acids from plant material and also defend plants from microbial or fungal attack? |
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Definition
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Term
| summarize secondary compounds: |
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Definition
| in summary, the diversity of both physical defenses and of secondary compounds is one line of evidence suggesting that herbivores have greatly influenced the evolution of plants |
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Term
| what has chemical diversity of plants aided? |
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Definition
| it has aided in the production of chemical defenses by animals |
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Term
| what are some animals dependent upon ? |
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Definition
| dependent upon their host plant for their defenses |
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Term
| What is constitutive defense? |
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Definition
| its when plants usually produce a certain quantity of a chemical defense, a sort of background amount. |
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Term
| what happens after the plants is attacked? |
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Definition
| after a plant is attacked, the amount of these chemical usually increases |
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Term
| describe induced defense: |
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Definition
- in other cases, entirely new compounds are produced after an attack.
- such a reaction, known as an induced defense, to herbivore attack can be thought of as a parallel to the immune system in animals
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Term
|
Definition
- causes the production of endorphins and other peptide hormones
- which help release supplies of arachidonic acid, the most common fatty acid in animal cell membranes
- which gets converted to prostaglandins
- which stimulate inflammation and activate the immune system to fight infection
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Term
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Definition
- causes the production of a PEPTIDE HORMONE
- which helps release supplies of LINOLENIC ACID, the most common fatty acid in plant cell membranes...
- which gets converted to JASMONIC ACID
- which stimulates the production of proteinase inhibitors and cholecystokinin to DETER INSECT PREDATORS
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Term
| how do plant communicate with each other? |
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Definition
- Jasmonic Acid and Methyl Jasomate are the likely inducing compounds. Both compounds elicit a multitude of responses in plants.
- Mechanical wounding increases the levels of Jasmonic Acid, which then move rapidly through the phloem.
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Term
| what will result if there is damage to a plant? |
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Definition
Damage to a plant may result in an induction of chemical defenses in neighboring plants
-several experiments have shown that volatile chemicals are released when plants are damaged |
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Term
| There is also evidence is that volatile cues from damaged plant tissues may be used as what? |
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Definition
| as cues for both herbivores and the predators and parasites of these herbivores, to locate these plants |
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Term
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Definition
| New leaves are ephemeral and somewhat unapparent, in that their characteristics change |
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Term
| What are young leaves usually like? |
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Definition
| young leaves are usually less tough, higher in water and protein content, and lower in defensive compounds, particularly of the quantitative type |
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Term
| what happens as leaves age? |
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Definition
| as a leaf ages, it increases its quantitative defenses, becomes tougher through changes in fiber on lignin content, and its protein and moisture contens drop |
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Term
| list some of community level effects: |
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Definition
- herbivores and predators can have a multitude of effects (keystone species concept)
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Term
| what happens to plant community when prairie dogs are around? |
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Definition
| With prairie dogs, the plant community is 47% grasses and 53% dicots (herbs) |
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Term
| What happens when prairie dogs are eliminated? |
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Definition
| With prairie dogs are eliminated the community consists of 87% grasses and 13% herbaceous dicots |
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