Lecture 24: Biotic Environment Flashcards

1
Q

Name the 3 different ways organisms can live together

A

Mutualistic
Parasitic
Commensalism

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2
Q

Mutualistic interaction

A

When both organisms benefit from interactions with one another

Examples: plant-pollinator interactions, plant-rhizobium interactions

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3
Q

Parasitic interaction

A

An interaction that is clearly detrimental to one organism

Examples: pathogen, parasite infection, negative allelopathy

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4
Q

Commensalism

A

One organisms gains a benefit while the other doesn’t

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5
Q

How are some agricultural practices harmful to mutualistic interactions?

A

Flooding, plowing, high fertilization, and soil fumigation decrease mutualistic associations

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6
Q

Ectomycorriza

A

External mycelium of the fungi that greatly increases soil exploration capacity for the plant

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7
Q

Endomycorriza

A

Plant-arbuscular association in which the fungi also grows inside the plant cell

Arbuscle: a branched treelike organ. specifically, one of the treelike haustorial organs in certain mycorrhizal fungi

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8
Q

What happens over time to a pest’s virulence (harmfulness)?

A

It decreases because it’s not in the pest’s best interest to kill its host

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9
Q

What has happened to the amount of non-native insects and pathogens over time?

A

It has greatly increased in the U.S

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10
Q

What is the most common way of transforming dicots?

A

Using agrobacterium tumefaciens to insert a piece of its DNA into the plant’s genome

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11
Q

Pierce’s disease of vines

A

The bacteria Xylella fastidiosa is carried to vines by insect vectors. The bacteria multiply and block the xylem

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12
Q

Methods to control Pierce’s disease of vines

A

Monitor and treat the vector
Remove infected vines
Grow less susceptible varieties

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13
Q

What are the two of the phyla of fungi that are the most species-rich?

A

Ascomycota and Basidiomycota

These phyla contain all mushrooms, most food-spoilage molds, most plant pathogenic fungi, and the beer, wine, and bread yeasts

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14
Q

Oomycota

A

Include the phytophthoras, one species of which causes potato blight

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15
Q

What is a special trait of Basidiomycetes?

A

They have basidium

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16
Q

What is a special trait of Ascodiomycetes?

A

The have asci

17
Q

What is a special trait of Oomycetes?

A

They have zoospores

18
Q

Wheat stripe rust

A

Caused by the basidiomycete Puccinia striiformis and is a serious fungal disease for wheat

Survives seasons on volunteer plants. Spreads quickly

19
Q

How to control wheat stripe rust

A

Plant resistant cultivars
Scout to detect early and use fungicides
Remove volunteer plants

20
Q

Nematodes

A

Attack the roots of plants and cause damage

21
Q

How to control nematodes

A

Use soil fumigation or solarization

22
Q

Insect effect on plants

A

Some are beneficial, like honeybees and ladybugs

Some are harmful, and can:
Chew and eat plant tissue
Suck out the contents of cells/phloem
Spread disease

23
Q

Weeds effect on plants

A

Compete with plants for resources
Contaminate harvest
Can be toxic to crops/animals
Harbor other pests

24
Q

What was the problem with pesticides in the past?

A

Their indiscriminate and extensive use

25
Q

What integrated approach should be used instead of heavy reliance on pesticides?

A

Integrated pest management (IPM)

26
Q

What are the 5 principles of IPM?

A

1) Doesn’t try to eradicate pests, but to keep them below the economic threshold
2) Farm is viewed as a whole unit
3) Use of natural control agents is maximized
4) Recognizes that control procedures may cause unexpected effects
5) Uses an interdisciplinary approach

27
Q

How should IPM start?

A

Preventative cultural methods

28
Q

What are examples of preventative cultural and physical/mechanical methods?

A

Crop rotation, companion planting, breeding for pest-resistance, mulches, plowing, use of cover crops, eliminating vectors or reservoirs