lecture 3: climate

Question 1

what are seasons

Answer 1

temporal pattern in temperature

Question 2

why do season fall unevenly

Answer 2

because Earth is tilted on its axis

-if Earth was not tilted on its axis, there would be no season

Question 3

correlation b/w humidity and temperature

Answer 3

• the capacity of air to hold moisture increases with increasing temperature
• as air cools, water is shed via condensation
• as air warms, air is sucked up by evaporation\
• cooling air can force precipitation, warming air can increase evaporation and transpiration
• warm air is less dense than cool air so it rises

Question 4

coriolis effect

Answer 4

• air masses flow clockwise in N hemisphere
• air masses flow counter clockwise in S hemisphere (b/c Earth rotates from E to W, and earth moves faster at equator and slower as you move away)
• this prevents the simple flow of air from equator to the poles
• as air moves to greater circumference, it deflects in the direction opposite of the spin (e.g. air coming down for 30 deg north to equator)
• as air moves to a lesser circumference, air deflects in the direction of the spin

-creates prevailing winds, influences ocean currents, explains why our weather usually comes from the West and moves past to East

Question 5

where are the bands of dry and high pressure?

Answer 5

30 degrees both sides, and North Pole and South Poles

Question 6

where are the bands of moist and low pressure

Answer 6

equator and 60 degrees both sides

Question 7

what would the climate be if earth was uniform

Answer 7

we would have continuous belts or temperature, pressure and precipitation

-but land masses, currents, mountains, etc disrupt this patter so we get semi-permanent high and pressure cells

Question 8

rain shadow effect

Answer 8

the presence of mountain ranges tends to produce extremes in precipitation (e.g. BC has lots of rain and Alberta no rain)

Question 9

how oceans affect weather

Answer 9

oceans absorb heat from the atmosphere in the summer, and releases heat to the atmosphere in winter, so it moderates temperatures

Question 10

snow belts

Answer 10

air picks up moisture from lakes in winter and you get snow

Question 11

great tit

Answer 11

egg laying early leads to starvation

(bc previously available food is not as abundant at an earlier time of year- in this case bird hatched eggs earlier bc of climate change)

Question 12

effects of climate change

Answer 12

• great tit: bird eggs laid earlier led to starvation

- warmer late winter weather causes plants to bud earlier making them vulnerable to late-season frost

Question 13

biogeography

Answer 13

-the study of how organisms are distributed georaphically

study of past and present geographical distribution of species and their ecological relationships

Question 14

dispersal

Answer 14

the movement of an individual from its place of origin to the location where it lives and breeds as an adult

-blocking dispersal can limit the distribution of the species (e.g. no kangaroos in NA although habitat is appropriate)

Question 15

what limits dispersal

Answer 15

1. abiotic factors
   - intertidal zones: major changes in temperature, water availability, salinity
   - upper limits of spp distributions are set by environmental tolerances and performance optima
2. biological factors
   - cows cannot survive where tsetse flies are found (transmit deadly parasite when it bites)