SABS Exam 2

An interaction between two biological species

(a)  

Symbiosis in which the species cannot exist without the other

(a)  

Symbiosis in which the species do not depend on each other for survival

(a)  

Which of the following are types of symbiosis?

• mutualism (both benefit)
• commensalism (one benefits on is ambivalent)
• parasitism (one benefits, other is harmed)
• mutualism (one benefits one is ambivalent)
• commensalism (both benefit)

What is true about Demodex Mites?

• common in eyelash and sebaceous glands
• once thought to be harmless commensals now implicated in blepharitis and acne rosacea
• can lead to redness, vessels proliferation, and dry eye due to Meibomian gland dysfunction
• symptoms can be an allergic reaction to the mites or the bacteria that infects the mites
• least effective treatment is tea tree oil

Diagnosis of this mite requires genty pulling out an eyelash so find the mite at the base of the eyelash.

(a)  

What is true about acne rosacea?

• presence of demodex mites is very common (could be result or cause)
• common skin condition (more common in women)
• rarely occurs around middle age
• symptoms flare up and then quiet down
• facial redness, visible blood vessels, red pus-filled bumps similar acne, and can cause an enlarged nose (rhinophyma)

Blepharitis, regardless of the cause, can be treated using a clean wash cloth with warm water and a few drops of tea tree oil.

• T
• F

(a)   organisms live on dead or decaying matter (ie fungi on dead trees).

(a)   : benefit at the expense of the host (includes bacteria, protozoans, multicellular organisms)