Lecture 24: Biotic Environment Flashcards
Name the 3 different ways organisms can live together
Mutualistic
Parasitic
Commensalism
Mutualistic interaction
When both organisms benefit from interactions with one another
Examples: plant-pollinator interactions, plant-rhizobium interactions
Parasitic interaction
An interaction that is clearly detrimental to one organism
Examples: pathogen, parasite infection, negative allelopathy
Commensalism
One organisms gains a benefit while the other doesn’t
How are some agricultural practices harmful to mutualistic interactions?
Flooding, plowing, high fertilization, and soil fumigation decrease mutualistic associations
Ectomycorriza
External mycelium of the fungi that greatly increases soil exploration capacity for the plant
Endomycorriza
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
What happens over time to a pest’s virulence (harmfulness)?
It decreases because it’s not in the pest’s best interest to kill its host
What has happened to the amount of non-native insects and pathogens over time?
It has greatly increased in the U.S
What is the most common way of transforming dicots?
Using agrobacterium tumefaciens to insert a piece of its DNA into the plant’s genome
Pierce’s disease of vines
The bacteria Xylella fastidiosa is carried to vines by insect vectors. The bacteria multiply and block the xylem
Methods to control Pierce’s disease of vines
Monitor and treat the vector
Remove infected vines
Grow less susceptible varieties
What are the two of the phyla of fungi that are the most species-rich?
Ascomycota and Basidiomycota
These phyla contain all mushrooms, most food-spoilage molds, most plant pathogenic fungi, and the beer, wine, and bread yeasts
Oomycota
Include the phytophthoras, one species of which causes potato blight
What is a special trait of Basidiomycetes?
They have basidium
What is a special trait of Ascodiomycetes?
The have asci
What is a special trait of Oomycetes?
They have zoospores
Wheat stripe rust
Caused by the basidiomycete Puccinia striiformis and is a serious fungal disease for wheat
Survives seasons on volunteer plants. Spreads quickly
How to control wheat stripe rust
Plant resistant cultivars
Scout to detect early and use fungicides
Remove volunteer plants
Nematodes
Attack the roots of plants and cause damage
How to control nematodes
Use soil fumigation or solarization
Insect effect on plants
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
Weeds effect on plants
Compete with plants for resources
Contaminate harvest
Can be toxic to crops/animals
Harbor other pests
What was the problem with pesticides in the past?
Their indiscriminate and extensive use
