Chapter 18

Question 1

definitions: ecology

Answer 1

the study of interactions between organisms and their environments

Question 2

definitions: population

Answer 2

same species in same place at the same time

Question 3

definitions: community

Answer 3

all organisms in same place

Question 4

definitions: ecosystem

Answer 4

community + physical environment (aka abiotic factors)

Question 5

What abiotic factors affect species distribution of the biosphere?

Answer 5

-nutrients : soils, rocks (as substate; minerals)
-water : rainfall, on land → threat of desiccation
-energy source : sunlight
-temp : range of 0C-45C
-wind : creates ocean currents; pollen carried by wind

Question 6

Define Biomes

Answer 6

major types of ecosystems that cover large geographic ares (aquatic, terrestrial)

Question 7

What determines the distribution of terrestrial biomes?

Answer 7

-climate : temperature; rainfall or physical features (mountains)
-main type of vegetation

Question 8

Describe the Chaparral biome of Southern California (p. 388) in terms of climate, vegetation (adaptations to drought). How are fires beneficial? What happens if they are prevented?

Answer 8

-mediterranean climate
-summers : hot, dry + long → periods of a drought + fires
-winter : mild + some rain → due to moderating effects of near ocean
-vegetations : dense, spiny evergreen shrubs adapted to periods of drought + fires

Question 9

Describe carbon dioxide emissions,

Answer 9

CO2 emissions → increase in CO2 since Industrial Revolution (1850’s)
-sources global warming
Sources:
- 80% burning of fossil fuels (oil, coal, gasoline); 20% deforestation

-for the last 650,000 years CO2 > 300 ppm (need to keep at ~ 350 ppm; now at >426 ppm)
-the problem: increase in CO2 and greenhouse gases

Question 10

the greenhouse effect

Answer 10

-act like a blanket of insulation to trap the solar radiation
-EX: CO2, methane (landfills, decomposing bacteria & cattle belch methane), and water vapor clouds and contrails

Question 11

global warming

Answer 11

big concern: climate change is so rapid that many species may not be able to adapt

Question 12

What are the possible long-term effects? (carbon emission)

Answer 12

-predict CO2 levels will double by the end of this century
-increase in average global temp (by 15C by 2030)
-warming greatest at poles → melting of polar ice → increase in sea levels by 100 m (330ft) → costal flooding

Question 13

What can be done? (carbon emission)

Answer 13

-need action on a global scale
1. decrease greenhouse gas emissions → global effects
2. renewable energy sources → solar, wind, nuclear power, biofuels
3. remove CO2; ex: green concrete, “ocean seeding”

Question 14

How are the oceans affected by excess CO2?

Answer 14

• pH decreases which increases in acidity in the ocean (100x faster than at any time in the geological past)
  -> potential problem for marine organisms may not be able to form their shells or exoskeletons (calcification can’t happen)

Question 15

How are the oceans affected by heat trapped by greenhouse gasses?

Answer 15

More than 90% of heat is trapped from greenhouse gases that raises sea levels (water expands as heated)

Question 16

Describe depletion of atmospheric ozone.

Answer 16

Since 1950s, decrease in ozone due to CFCs => in refrigerators, AC’s, aerosols

Question 17

what are the effects of depletion of atmospheric ozone.

Answer 17

Effects:
- predict an increase in skin cancer + cataracts
- damage to frog eggs
- damage to phytoplankton -> supplies more than or equal to 50% of O2 to our atmosphere

Question 18

what has been done about depletion of atmospheric ozone.

Answer 18

What has been done:
- in 1987, agreed to end CFC production by 2010 => Ozone degradation has slowed down, but will continue to degrade for at least a century