Courtney Guest Lecture

Question 1

Mammals cold weather adaptations

Answer 1

Dehnel’s Phenomenon:

• Reduced body weight
• Shortened length
• Reduced brain volume
• Reduced weight of kidney liver and spleen
• Decreased skull height
• Reduced intervertebral disks

Question 2

Invertebrate cold weather adaptations

Answer 2

Cyclomorphisis:
-Larger legs with more hair
Cold hardiness:
-Ability to resist freezing 
-Ability to supercool
-Ability to survive long exposure 
Anaerobiosis:
-Survive without oxygen

Question 3

Importance of high elevation ecosystems

Answer 3

• Over 1 billion people rely on high elevation snowfields for their freshwater.
• High elevation snow systems indirectly affect all other ecosystems.

Question 4

Why is high elevation snowpack in danger?

Answer 4

• Snow packs have been reduced by more than 10% since 1970.
• lower temperatures are increasing.
• climate change is affecting higher latitudes.
• Snow dust.

Question 5

Consequences of high elevation snowpack reduction

Answer 5

Climate change:

• Depth
• Duration
• Timing of spring melt
• Microbial activity
• Nutrient cycling
• Water shortage

Question 6

Main autotroph’s and main heterotrophs

Answer 6

Autotroph's:
-Algae
-Bacteria
Heterotroph's:
-Shrews
-Voles

Question 7

Chytrid Zoospores

Use pollen for shelter

Answer 7

-Zoospores are single celled and lack cell walls making them susceptible to osmotic pressure changes.
-most can’t handle freeze/thaw cycles.
Mechanism:
-Thick celled hyphae
-Spore state or cysts

Question 8

Food chain vs. food web

Answer 8

Food chain- linear relationship of who’s eating who.

Food web- Dynamic web of all relationships, not just who’s eating who.

Question 9

Carbon cycle

Answer 9

• High abundance of red snow algae puts carbon into the system through carbon fixation.
• the algae are in turn consumed passing carbon through the food chain.
• Wind transported dust brings in carbon sources that are broken down by bacteria and fungi.

Question 10

Nitrogen cycle

Answer 10

• gram-negative bacteria make up almost 20% of the bacteria found in snow and are nitrate reducers.
• cyanobacteria fix atmospheric nitrogen.
• Snow microbes are capable of nitrogen fixation, nitrification and nitrate reduction.